Published on in Vol 21, No 8 (2019): August

Preprints (earlier versions) of this paper are available at https://preprints.jmir.org/preprint/12687, first published .
A Comparison of Physical Activity Mobile Apps With and Without Existing Web-Based Social Networking Platforms: Systematic Review

A Comparison of Physical Activity Mobile Apps With and Without Existing Web-Based Social Networking Platforms: Systematic Review

A Comparison of Physical Activity Mobile Apps With and Without Existing Web-Based Social Networking Platforms: Systematic Review

Review

1College of Nursing and Health Sciences, Flinders University, Adelaide, Australia

2College of Education, Psychology and Social Work, Flinders University, Adelaide, Australia

Corresponding Author:

Jasmine Maria Petersen, BSc

College of Nursing and Health Sciences

Flinders University

GPO Box 2100

Adelaide,

Australia

Phone: 61 8 82013713

Email: jasmine.petersen@flinders.edu.au


Background: Physical activity mobile apps present a unique medium to disseminate scalable interventions to increase levels of physical activity. However, the effectiveness of mobile apps has previously been limited by low levels of engagement. Existing Web-based social networking platforms (eg, Facebook and Twitter) afford high levels of popularity, reach, and sustain engagement and, thus, may present an innovative strategy to enhance the engagement, and ultimately the effectiveness of mobile apps.

Objective: This study aimed to comparatively examine the effectiveness of, and engagement with, interventions that incorporate physical activity mobile apps in conjunction with and without existing Web-based social networking platforms (eg, Facebook and Twitter).

Methods: A systematic review was conducted by following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Guidelines. A systematic search of the following databases was conducted: Medline, PsycINFO, Web of Science, Scopus, CINAHL, ProQuest, SPORTDiscus, EMBASE, and Cochrane. According to the comparative objective of this review, 2 independent literature searches were conducted. The first incorporated terms related to apps and physical activity; the second also incorporated terms related to Web-based social networking. The results of the two searches were synthesized and compared narratively.

Results: A total of 15 studies were identified, 10 incorporated a physical activity app alone and 5 incorporated an app in conjunction with an existing Web-based social networking platform. Overall, 10 of the 15 interventions were effective in improving one or more physical activity behaviors. Specifically, improvements in physical activity behaviors were reported in 7 of the 10 interventions incorporating physical activity apps alone and in 3 of the 5 interventions incorporating physical activity apps in conjunction with existing Web-based social networking platforms. Interventions incorporating physical activity apps alone demonstrated a decline in app engagement. In contrast, the physical activity apps in conjunction with existing Web-based social networking platforms showed increased and sustained intervention engagement.

Conclusions: The interventions incorporating physical activity apps in conjunction with and without existing Web-based social networking platforms demonstrated effectiveness in improving physical activity behaviors. Notably, however, the interventions that incorporated existing Web-based social networking platforms achieved higher levels of engagement than those that did not. This review provides preliminary evidence that existing Web-based social networking platforms may be fundamental to increase engagement with physical activity interventions.

J Med Internet Res 2019;21(8):e12687

doi:10.2196/12687

Keywords



Physical inactivity is a global pandemic. Globally, 1.4 billion adults (28%) are not meeting the physical activity guidelines (150 min of physical activity per week), a figure that is steadily increasing [Guthold R, Stevens GA, Riley LM, Bull FC. Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1·9 million participants. Lancet Glob Health 2018 Dec;6(10):e1077-e1086 [FREE Full text] [CrossRef] [Medline]1]. This is of public health concern given the consistently documented benefits of physical activity, including a reduced risk of cardiovascular disease, hypertension, osteoporosis, diabetes mellitus, obesity, mental illness, and premature mortality [Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. Can Med Assoc J 2006 Mar 14;174(6):801-809 [FREE Full text] [CrossRef] [Medline]2-Lee I, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT, Lancet Physical Activity Series Working Group. Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. Lancet 2012 Jul 21;380(9838):219-229 [FREE Full text] [CrossRef] [Medline]4]. Thus, it is important to develop innovative, scalable interventions to increase levels of physical activity.

Advancements in mobile technology, specifically the development of mobile apps, present a unique medium to deliver interventions targeted at improving health behaviors. Mobile apps are software programs developed for mobile phones and tablets that hold potential to influence health behaviors owing to their widespread reach, accessibility, and convenience [Payne HE, Lister C, West JH, Bernhardt JM. Behavioral functionality of mobile apps in health interventions: a systematic review of the literature. JMIR Mhealth Uhealth 2015 Feb 26;3(1):e20 [FREE Full text] [CrossRef] [Medline]5]. Recently, there has been a proliferation of mobile health apps, with estimates of over 318,000 available for download, double the number available 2 years ago [Aitken M, Clancy B, Nass D. IQVIA. 2017. The Growing Value of Digital Health: Evidence and Impact on Human Health and the Healthcare System   URL: https://www.iqvia.com/institute/reports/the-growing-value-of-digital-health [accessed 2018-08-05] [WebCite Cache]6]. Among mobile health apps, physical activity apps account for the largest proportion (30%) and are expected to increase 87% faster than any other category of health app [Grand View Research. 2017. mHealth Apps Market Size, Share & Trends Analysis Report by Type (Fitness, Lifestyle Management, Nutrition & Diet, Women's Health, Medication Adherence, Healthcare Providers/Payers), and Segment Forecasts, 2019 - 2026   URL: https://www.grandviewresearch.com/industry-analysis/mhealth-app-market [accessed 2018-11-01] [WebCite Cache]7]. Despite the ever-increasing ubiquity of physical activity mobile apps, previous reviews have only demonstrated modest evidence from such apps in terms of the magnitude of their effectiveness to positively influence physical activity behavior [Schoeppe S, Alley S, van Lippevelde W, Bray NA, Williams SL, Duncan MJ, et al. Efficacy of interventions that use apps to improve diet, physical activity and sedentary behaviour: a systematic review. Int J Behav Nutr Phys Act 2016 Dec 7;13(1):127 [FREE Full text] [CrossRef] [Medline]8-Romeo A, Edney S, Plotnikoff R, Curtis R, Ryan J, Sanders I, et al. Can smartphone apps increase physical activity? Systematic review and meta-analysis. J Med Internet Res 2019 Mar 19;21(3):e12053 [FREE Full text] [CrossRef] [Medline]11]. This indicates that there is potential to improve the effectiveness of physical activity mobile apps.

The effectiveness of mobile apps is influenced by levels of engagement with the app [Schoeppe S, Alley S, van Lippevelde W, Bray NA, Williams SL, Duncan MJ, et al. Efficacy of interventions that use apps to improve diet, physical activity and sedentary behaviour: a systematic review. Int J Behav Nutr Phys Act 2016 Dec 7;13(1):127 [FREE Full text] [CrossRef] [Medline]8]. Specifically, a dose-response has been identified, such that increasing levels of engagement, and thus greater exposure to intervention content, is associated with improved behavioral outcomes [Poirier J, Cobb NK. Social influence as a driver of engagement in a web-based health intervention. J Med Internet Res 2012 Feb 22;14(1):e36 [FREE Full text] [CrossRef] [Medline]12]. Unfortunately, commercial research has identified a lack of commitment to sustained engagement with health and physical activity apps, reporting that few individuals (10%) engage with downloaded apps for more than 7 days [Dennison L, Morrison L, Conway G, Yardley L. Opportunities and challenges for smartphone applications in supporting health behavior change: qualitative study. J Med Internet Res 2013 Apr 18;15(4):e86 [FREE Full text] [CrossRef] [Medline]13,Grady A, Yoong S, Sutherland R, Lee H, Nathan N, Wolfenden L. Improving the public health impact of ehealth and mhealth interventions. Aust N Z J Public Health 2018 Apr;42(2):118-119. [CrossRef] [Medline]14]. An initial review of interventions incorporating physical activity apps also revealed rapid declines in app engagement over intervention periods of 3 and 9 months [Jee H. Review of researches on smartphone applications for physical activity promotion in healthy adults. J Exerc Rehabil 2017 Feb;13(1):3-11 [FREE Full text] [CrossRef] [Medline]15]. A more recent review further documented that interventions incorporating apps were effective only in the short term (<3 months), and this was purportedly linked to declining levels of engagement over time [Romeo A, Edney S, Plotnikoff R, Curtis R, Ryan J, Sanders I, et al. Can smartphone apps increase physical activity? Systematic review and meta-analysis. J Med Internet Res 2019 Mar 19;21(3):e12053 [FREE Full text] [CrossRef] [Medline]11]. This is concerning given that long-term engagement in physical activity behaviors is important to attain any associated health benefits [Jepson RG, Harris FM, Platt S, Tannahill C. The effectiveness of interventions to change six health behaviours: a review of reviews. BMC Public Health 2010 Sep 8;10:538 [FREE Full text] [CrossRef] [Medline]16]. It is clear that strategies are needed to enhance engagement with mobile apps targeted at increasing physical activity. This, however, requires a greater understanding of the specific features of mobile apps that may augment engagement, and ultimately enhance their effectiveness.

An important consideration in the endeavor to improve the effectiveness of physical activity mobile apps is the appropriate utilization of behavior change theory. This is fundamental as the existing empirical literature has consistently identified that effective physical activity interventions are informed by theory [Glanz K, Bishop DB. The role of behavioral science theory in development and implementation of public health interventions. Annu Rev Public Health 2010;31:399-418. [CrossRef] [Medline]17,Webb TL, Joseph J, Yardley L, Michie S. Using the internet to promote health behavior change: a systematic review and meta-analysis of the impact of theoretical basis, use of behavior change techniques, and mode of delivery on efficacy. J Med Internet Res 2010 Feb 17;12(1):e4 [FREE Full text] [CrossRef] [Medline]18]. However, previous research within the realm of physical activity interventions incorporating mobile apps has documented that the utilization of behavior change theory is largely lacking [Bondaronek P, Alkhaldi G, Slee A, Hamilton FL, Murray E. Quality of publicly available physical activity apps: review and content analysis. JMIR Mhealth Uhealth 2018 Mar 21;6(3):e53 [FREE Full text] [CrossRef] [Medline]19-Cowan LT, van Wagenen SA, Brown BA, Hedin RJ, Seino-Stephan Y, Hall PC, et al. Apps of steel: are exercise apps providing consumers with realistic expectations?: a content analysis of exercise apps for presence of behavior change theory. Health Educ Behav 2013 Apr;40(2):133-139. [CrossRef] [Medline]22]. In addition, among the physical activity apps that are informed by theory, a diverse range of theories have been utilized including the Health Belief Model; Transtheoretical Model; Self-determination Theory; and Social Cognitive Theory [Bondaronek P, Alkhaldi G, Slee A, Hamilton FL, Murray E. Quality of publicly available physical activity apps: review and content analysis. JMIR Mhealth Uhealth 2018 Mar 21;6(3):e53 [FREE Full text] [CrossRef] [Medline]19-Cowan LT, van Wagenen SA, Brown BA, Hedin RJ, Seino-Stephan Y, Hall PC, et al. Apps of steel: are exercise apps providing consumers with realistic expectations?: a content analysis of exercise apps for presence of behavior change theory. Health Educ Behav 2013 Apr;40(2):133-139. [CrossRef] [Medline]22]. This has limited the formation of conclusions regarding the most appropriate theoretical foundation(s) to inform the development of apps [Stuckey MI, Carter SW, Knight E. The role of smartphones in encouraging physical activity in adults. Int J Gen Med 2017;10:293-303 [FREE Full text] [CrossRef] [Medline]23].

Behavior change theories are important in isolating specific features to incorporate into an intervention that will effectively facilitate behavior change. Given this, it is not surprising that an emerging body of research examining the content of physical activity mobile apps has identified that apps are lacking in the inclusion of features underpinned by behavior change theory [Bondaronek P, Alkhaldi G, Slee A, Hamilton FL, Murray E. Quality of publicly available physical activity apps: review and content analysis. JMIR Mhealth Uhealth 2018 Mar 21;6(3):e53 [FREE Full text] [CrossRef] [Medline]19-Cowan LT, van Wagenen SA, Brown BA, Hedin RJ, Seino-Stephan Y, Hall PC, et al. Apps of steel: are exercise apps providing consumers with realistic expectations?: a content analysis of exercise apps for presence of behavior change theory. Health Educ Behav 2013 Apr;40(2):133-139. [CrossRef] [Medline]22]. Nevertheless, the limited theory-driven research to date has identified one particular feature, namely social support, that has been consistently incorporated into physical activity mobile apps and is underpinned by a myriad of behavior change theories [Bondaronek P, Alkhaldi G, Slee A, Hamilton FL, Murray E. Quality of publicly available physical activity apps: review and content analysis. JMIR Mhealth Uhealth 2018 Mar 21;6(3):e53 [FREE Full text] [CrossRef] [Medline]19-Cowan LT, van Wagenen SA, Brown BA, Hedin RJ, Seino-Stephan Y, Hall PC, et al. Apps of steel: are exercise apps providing consumers with realistic expectations?: a content analysis of exercise apps for presence of behavior change theory. Health Educ Behav 2013 Apr;40(2):133-139. [CrossRef] [Medline]22]. Social support is commonly integrated into apps via Web-based social networking, which allows individuals to construct a personal profile and connect with other users [Mollee J, Middelweerd A, Kurvers R, Klein M. What technological features are used in smartphone apps that promote physical activity? A review and content analysis. Pers Ubiquit Comput 2017 Jul 5;21(4):633-643. [CrossRef]21]. Web-based social networks incorporated into physical activity mobile apps have a range of functionalities, including features that allow users to share physical activity data, receive likes and comments on their behavior (facilitating social interactions), and thus foster the provision of social support [Mollee J, Middelweerd A, Kurvers R, Klein M. What technological features are used in smartphone apps that promote physical activity? A review and content analysis. Pers Ubiquit Comput 2017 Jul 5;21(4):633-643. [CrossRef]21].

Typically, social support has been documented as a fundamental component of health interventions delivered face to face and has been associated with increased intervention engagement [Poirier J, Cobb NK. Social influence as a driver of engagement in a web-based health intervention. J Med Internet Res 2012 Feb 22;14(1):e36 [FREE Full text] [CrossRef] [Medline]12,Perski O, Blandford A, West R, Michie S. Conceptualising engagement with digital behaviour change interventions: a systematic review using principles from critical interpretive synthesis. Transl Behav Med 2017 Dec;7(2):254-267 [FREE Full text] [CrossRef] [Medline]24] and sustained behavior change [Courneya KS, Plotnikoff RC, Hotz SB, Birkett NJ. Social support and the theory of planned behavior in the exercise domain. Am J Health Behav 2000 Jul 1;24(4):300-308. [CrossRef]25]. Although face-to-face interventions may effectively facilitate high levels of support through interpersonal interactions, several limitations including time, cost, and resource intensiveness may hinder the viability of such interventions. Web-based social networks overcome many of the barriers of face-to-face interventions and afford several advantages including greater accessibility of immediate and continuous support, anonymity, and wide reach. Additionally, Web-based social networks incorporated into Web-based interventions targeting weight-related outcomes (eg, body weight and body mass index [BMI]) have demonstrated that the support provided is comparable with that attained in face-to-face interventions [Bennett GG, Herring SJ, Puleo E, Stein EK, Emmons KM, Gillman MW. Web-based weight loss in primary care: a randomized controlled trial. Obesity (Silver Spring) 2010 Feb;18(2):308-313 [FREE Full text] [CrossRef] [Medline]26]. Thus, it has been suggested that the support provided by Web-based social networks may emulate the interpersonal support achieved through face-to-face interventions [Santarossa S, Kane D, Senn CY, Woodruff SJ. Exploring the role of in-person components for online health behavior change interventions: can a digital person-to-person component suffice? J Med Internet Res 2018 Dec 11;20(4):e144 [FREE Full text] [CrossRef] [Medline]27]. Evidently, Web-based social networking may be valuable in facilitating the provision of social support and fundamental in enhancing intervention engagement and thus effectiveness.

Previous research has ascertained 2 types of Web-based social networks incorporated into health interventions: (1) health-focused social networks (ie, networks developed by a researcher or integrated into health apps allowing users to connect with other users), and (2) existing social networking platforms (eg, Facebook and Twitter) [Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28,Laranjo L, Arguel A, Neves AL, Gallagher AM, Kaplan R, Mortimer N, et al. The influence of social networking sites on health behavior change: a systematic review and meta-analysis. J Am Med Inform Assoc 2015 Jan;22(1):243-256 [FREE Full text] [CrossRef] [Medline]29]. In total, 2 systematic reviews have examined interventions (predominately Web-based) targeting health behaviors, including obesity, physical activity, sexual health, and smoking cessation, that either incorporated or were exclusively delivered via Web-based social networks (health-focused and existing) [Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28,Laranjo L, Arguel A, Neves AL, Gallagher AM, Kaplan R, Mortimer N, et al. The influence of social networking sites on health behavior change: a systematic review and meta-analysis. J Am Med Inform Assoc 2015 Jan;22(1):243-256 [FREE Full text] [CrossRef] [Medline]29]. These reviews demonstrated positive effects of Web-based social networking in modifying health behaviors [Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28,Laranjo L, Arguel A, Neves AL, Gallagher AM, Kaplan R, Mortimer N, et al. The influence of social networking sites on health behavior change: a systematic review and meta-analysis. J Am Med Inform Assoc 2015 Jan;22(1):243-256 [FREE Full text] [CrossRef] [Medline]29]. However, neither review [Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28,Laranjo L, Arguel A, Neves AL, Gallagher AM, Kaplan R, Mortimer N, et al. The influence of social networking sites on health behavior change: a systematic review and meta-analysis. J Am Med Inform Assoc 2015 Jan;22(1):243-256 [FREE Full text] [CrossRef] [Medline]29] was able to identify the differing effectiveness of health-focused and existing Web-based social networks on influencing health outcomes and levels of engagement, as the 2 types of social networks were not evaluated independently. Notably, in both reviews, it was proposed that the inherent nature of existing Web-based social networking platforms may be harnessed to address issues of engagement and reach, ultimately enhancing the effectiveness of health interventions [Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28,Laranjo L, Arguel A, Neves AL, Gallagher AM, Kaplan R, Mortimer N, et al. The influence of social networking sites on health behavior change: a systematic review and meta-analysis. J Am Med Inform Assoc 2015 Jan;22(1):243-256 [FREE Full text] [CrossRef] [Medline]29].

A recent meta-analysis [An R, Ji M, Zhang S. Effectiveness of social media-based interventions on weight-related behaviors and body weight status: review and meta-analysis. Am J Health Behav 2017 Nov 1;41(6):670-682. [CrossRef] [Medline]30] of interventions (eg, Web-based, face-to-face, and text messaging) targeting weight-related behaviors (eg, physical activity) and body weight status (eg, BMI) that either incorporated or were exclusively delivered via existing Web-based social networking platforms reported that these interventions produced significant reductions in body weight, BMI, and waist circumference, and significantly increased the average number of daily steps. This demonstrates that interventions incorporating, or exclusively delivered via existing Web-based social networking platforms, have the capacity to effectively modify a range of health-related outcomes. This may be attributed to the unique nature of existing Web-based social networking platforms, including their enormous popularity and widespread reach, with over 2.46 billion users worldwide, a figure that is continuing to rise [Statista. 2019. Number of Monthly Active Facebook Users Worldwide as of 1st Quarter 2019 (in Millions)   URL: https://www.statista.com/statistics/264810/number-of-monthly-active-facebook-users-worldwide/ [accessed 2019-04-09] [WebCite Cache]31]. Additionally, existing Web-based social networking platforms achieve high levels of sustained engagement, with estimates that 76% of Facebook users log in daily, 51% engage multiple times per day, and 70% continue to use the platform after 24 months [Statista. 2019. Number of Monthly Active Facebook Users Worldwide as of 1st Quarter 2019 (in Millions)   URL: https://www.statista.com/statistics/264810/number-of-monthly-active-facebook-users-worldwide/ [accessed 2019-04-09] [WebCite Cache]31]. Therefore, interventions that incorporate existing Web-based social networking platforms may achieve heightened effectiveness in their capacity to reach large audiences and sustain high levels of engagement.

Previously, no review has exclusively examined the effectiveness of interventions that incorporate physical activity mobile apps in conjunction with existing Web-based social networking platforms. The high prevalence of physical activity mobile apps, coupled with the promising capabilities of existing Web-based social networking platforms to augment app effectiveness, highlights an important avenue that warrants examination. Thus, this review examined the influence of existing Web-based social networking platforms on the effectiveness of, and engagement with, mobile apps that target physical activity. To isolate the influence of existing Web-based social networking platforms, this review provides a comparison between interventions that incorporate physical activity mobile apps in conjunction with and without existing Web-based social networking platforms.


Overview

The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines [Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 2009 Jul 21;6(7):e1000097 [FREE Full text] [CrossRef] [Medline]32] (see Figures 1 and Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. Can Med Assoc J 2006 Mar 14;174(6):801-809 [FREE Full text] [CrossRef] [Medline]2) and was registered with the International Prospective Register of Systematic Review (registration number CRD42018106456). An academic health librarian assisted with the development of the search strategy. The search strategy incorporated key terms and thesaurus terms related to mobile apps (eg, application, app, mobile phone, and iPhone), physical activity (eg, exercise, fitness, sports, inactive, and sedentary behavior) and Web-based social networks (eg, social network, social medium, Facebook, Twitter, and Instagram; see Multimedia Appendices 1 and Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. Can Med Assoc J 2006 Mar 14;174(6):801-809 [FREE Full text] [CrossRef] [Medline]2 for complete search strategy). However, according to the comparative aims of this review, 2 independent searches were conducted, which differed such that one incorporated the terms related to apps and physical activity (app-alone search) and the other also incorporated the terms related to Web-based social networking (app Web-based social networking search). Both searches were conducted on the July 3, 2018, using the following 9 databases: Medline, PsycINFO, Web of Science, Scopus, CINAHL, ProQuest, SPORTDiscus, EMBASE, and Cochrane. The search results were limited to the English language, peer-reviewed, and year of publication between 2007 (the year smartphones were introduced) and the July 3, 2018.

Inclusion Criteria and Study Selection

Studies from the 2 independent searches were selected if (1) a mobile app was incorporated as the main component of the intervention; (2) the primary or secondary outcome was to promote physical activity; (3) physical activity outcomes were reported; and (4) baseline and postintervention assessments of physical activity outcomes were included. The inclusion criteria differed slightly between the 2 searches to fulfill the comparative aims of the review. Specifically, the first search, termed app-alone, attempted to exclusively isolate the effect of physical activity apps, such that studies were deemed relevant if they did not incorporate any type of Web-based social network (health-focused or existing) or social component. Conversely, to ascertain the additive effects of an existing Web-based social network over and above that of an app, the second search, termed app Web-based social networking, required studies to specifically incorporate an existing Web-based social networking platform (eg, Facebook and Twitter) into their design. Included studies utilized an experimental or within-subjects pre-post design to determine the effectiveness of the intervention. Studies incorporating populations capable of engaging in physical activity were eligible for inclusion. In total, 2 reviewers independently screened the titles, abstracts, and full-text papers for eligibility and any disagreements were resolved by discussion. Forward (screening the citations of included studies) and backward (screening the reference lists of included studies) searching was conducted to ensure all relevant publications were identified.

Data Extraction

Data extraction was conducted by the first author using a standardized form developed for this review. Extracted information included sample characteristics, study design, features of the mobile app, details of the Web-based social network, physical activity outcomes (time points reported), any additional outcomes reported (eg, engagement and psychosocial outcomes), and behavior change theories reported.

Figure 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart: App-alone search.
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Figure 2. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart: App Web-based Social Networking Search.
View this figure

Reporting of Methodological Characteristics

A 25-item tool devised by Maher et al [Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28] based on the Consolidated Standards of Reporting Trials (CONSORT) checklist [Moher D, Hopewell S, Schulz KF, Montori V, Gøtzsche PC, Devereaux PJ, et al. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. Br Med J 2010 Mar 23;340:c869 [FREE Full text] [CrossRef] [Medline]33] that examines reported methodological characteristics was used to assess methodological risk of bias. The tool was deemed to be relevant for this study as most of the items (20 out of 25) were applicable to both pre-post designs and randomized controlled trials [Romeo A, Edney S, Plotnikoff R, Curtis R, Ryan J, Sanders I, et al. Can smartphone apps increase physical activity? Systematic review and meta-analysis. J Med Internet Res 2019 Mar 19;21(3):e12053 [FREE Full text] [CrossRef] [Medline]11,Maher CA, Lewis LK, Ferrar K, Marshall S, de Bourdeaudhuij I, Vandelanotte C. Are health behavior change interventions that use online social networks effective? A systematic review. J Med Internet Res 2014 Feb 14;16(2):e40 [FREE Full text] [CrossRef] [Medline]28]. The checklist was scored according to the extent to which each item was (1) fulfilled; (0.5) partially fulfilled; and (0) not fulfilled. A higher score is indicative of a lower risk of bias. In total, 2 independent reviewers assessed all included studies, and any disagreements were discussed and resolved.

Data Synthesis

The primary outcome was physical activity behavior. The secondary outcomes included engagement with the intervention and psychosocial outcomes related to physical activity. In line with the comparative aims of the review, the app-alone and app Web-based social networking studies were compared in relation to both the primary and secondary outcomes. To determine whether the interventions effectively improved physical activity behavior, P values were evaluated. Specifically, interventions that were randomized controlled trials were identified to be effective if significant differences between groups across time were reported. Interventions of a pre-post study design were identified to be effective if significant changes across time were reported. Effect sizes were also examined and taken into account when evaluating the effectiveness of the interventions. The benchmark criteria for effect sizes are 0.20 for a small effect, 0.50 for a medium effect, and 0.80 for a large effect [Cohen J. A power primer. Psychol Bull 1992 Jul;112(1):155-159. [CrossRef] [Medline]34].


Study Selection

The first database search (app-alone) identified 15,576 studies, following the removal of duplicates. Title and abstract screening deemed 15,544 studies ineligible for inclusion. In total, 32 full-text articles were screened for inclusion, with 23 studies excluded at this point (see Figure 1 for reasons). Forward and backward searching identified 1 additional study that was eligible for inclusion. A total of 10 app-alone studies were deemed relevant according to the predefined criteria and thus were included in this review (Figure 1).

The second database search (app Web-based social networking) identified 4165 studies, after removing duplicates. Title and abstract screening identified 4151 ineligible studies. In total, 14 full-text articles were screened for inclusion, resulting in 10 studies being excluded (see Figure 2 for reasons). Screening of reference lists and forward searching identified 1 additional study that was eligible for inclusion. A total of 5 studies were deemed suitable to be included in this review (Figure 2).

Thus, the following review included a total of 15 studies. Of these, 10 studies used an app alone, and 5 studies incorporated an app in conjunction with an existing Web-based social networking platform. These numbers of studies are similar to those of a recent comparative review [Nour M, Yeung SH, Partridge S, Allman-Farinelli M. A narrative review of social media and game-based nutrition interventions targeted at young adults. J Acad Nutr Diet 2017 May;117(5):735-52.e10. [CrossRef] [Medline]35].

Characteristics of Included Studies

The characteristics of the app-alone studies are tabulated in

Multimedia Appendix 3

Characteristics of app-alone studies.

PDF File (Adobe PDF File), 122KBMultimedia Appendix 3 and those of the app Web-based social networking studies are tabulated in

Multimedia Appendix 4

Characteristics of app Web-based social networking studies.

PDF File (Adobe PDF File), 88KB
Multimedia Appendix 4
. The app-alone and app Web-based social networking studies were comparable in years of publication and the countries where the studies were conducted. However, the study designs differed such that the app-alone studies predominately utilized an experimental design (n=7) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], whereas the app Web-based social networking studies predominantly utilized within-subjects pre-post designs (n=4) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43-Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Across the 7 app-alone studies that utilized an experimental design, the control groups received either a no intervention control (n=1) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40]; minimal intervention (eg, accelerometer or print materials; n=5) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42]; or an app that differed slightly (fewer features; n=1) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41]. In contrast, the 1 app Web-based social networking study that included a control utilized a waitlisted control condition [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]. Among all included studies, 2 app Web-based social networking studies [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47] aimed to modify physical activity in conjunction with dietary quality. Across the app-alone and app Web-based social networking studies, a greater number of interventions utilized newly designed apps (n=10) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40-Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] than commercially available apps (n=5) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. The app-alone and app Web-based social networking studies incorporated samples that were similar in size, age, and the predominance of female participants. The samples that were composed of women, were women who were healthy [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43], overweight and obese [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], insufficiently active [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], or nurses [Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. Although both the app-alone and app Web-based social networking studies largely recruited from a specific population (n=11) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40-Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], disparities were noted among the app-alone and app Web-based social networking studies in relation to the populations recruited. Specifically, the app-alone interventions recruited samples that were sedentary (n=3) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], low active (n=3) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], obese or overweight (n=2) [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], in primary care (n=1) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36], pregnant (n=1) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38], or diagnosed with type 2 diabetes (n=1) [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]. Contrastingly, the app Web-based social networking interventions targeted samples that were nurses (n=2) [Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45], breast cancer survivors (n=1) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], and obese or overweight (n=1) [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]. The average intervention duration for app-alone studies ranged from 1 week [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40] to 14 weeks [Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], comparable with the intervention durations of the app Web-based social networking studies that ranged from 3 weeks [Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44] to 3 months [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. One app-alone study incorporated a 3-month follow-up assessment [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], whereas 2 app Web-based social networking studies incorporated follow-up assessments at 1 week postintervention [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] and 6 months postintervention [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45].

Among the app-alone and app Web-based social networking studies, all apps targeted aerobic physical activity including light physical activity (n=6) [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], moderate physical activity (n=2) [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], moderate-to-vigorous physical activity (MVPA; n=6) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45-Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], vigorous physical activity (n=2) [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], and daily steps (n=9) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42-Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]. The apps incorporated a diverse range of features targeted at encouraging physical activity, including monitoring or tracking of behavior (n=9) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46-Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], feedback (n=7) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40-Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43], information or education relating to physical activity (n=4) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47], goal setting (n=5) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41-Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], and reinforcements (n=4) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]. Both the app-alone and app Web-based social networking studies were underpinned by a diverse range of behavior change theories, namely the Social Cognitive Theory [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], Self-determination Theory [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39], Control Theory [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45], Goal-Setting Theory [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45], attitude-social influence self-efficacy model [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], the Behavior Change Wheel [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37], and the Theory of Reasoned Action [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43].

Description of the Existing Web-Based Social Networks

Among the app Web-based social networking studies, all 5 incorporated Facebook as the existing Web-based social networking platform; however, this platform was differentially utilized. In total, 2 studies provided participants with a link to a private Facebook group [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]; and 1 study incorporated a public Facebook page that included educational tips related to physical activity and participants were encouraged to comment and generate posts [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Alternatively, in 2 studies, the app had the functionality to connect to Facebook, whereby participants could share their physical activity data and receive likes and comments [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44]. The existing Web-based social networks most often utilized features that facilitated social interaction (sharing physical activity posts, liking or commenting on others posts, and communicating with others; n=5) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43-Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47], social comparison (viewing posts of others’ physical activity performance; n=3) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], and competition (ranking table and group averages; n=2) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44].

Measures of Physical Activity and Additional Outcomes

Both the app-alone and app Web-based social networking studies primarily measured physical activity objectively (n=14) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], specifically by utilizing an accelerometer (n=8) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41-Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45-Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], pedometer (n=3) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44], Fitbit (n=2) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] or inclinometer (n=1) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40]. Among all included studies, 2 app-alone studies measured physical activity by self-report, specifically by using the International Physical Activity Questionnaire (IPAQ)-Long form [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and IPAQ-Short form [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39]. Physical activity outcomes predominantly targeted for modification included light physical activity (n=6) [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], moderate physical activity (n=2) [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], MVPA (n=6) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45-Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], vigorous physical activity (n=2) [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], daily steps (n=9) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42-Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], or sedentary behavior (n=5) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]. Across all studies, the underlying psychosocial outcomes related to physical activity (ie, self-efficacy and exercise motivation) were assessed by 4 app-alone studies [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 2 app Web-based social networking studies [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46].

The Effectiveness of the Intervention

Table 1 provides a summary of the intervention effects on physical activity outcomes. Across all included studies, 10 of the 15 interventions effectively improved one or more physical activity behaviors [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], including 7 of the 10 app-alone interventions [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] and 3 of the 5 app Web-based social networking interventions [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Improvements were reported in either the intervention conditions relative to a control condition (n=3) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40] or over time (n=7) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] for one or more physical activity behaviors. Specifically, the physical outcomes reported were increases in daily steps (n=6) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]; increases in light physical activity (n=2) [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]; increases in MVPA (n=3) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48]; and decreases in sedentary behavior (n=3) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48]. In total, 5 studies, 3 app-alone studies [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 2 app Web-based social networking studies [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47], did not find an intervention effect across groups [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47] or across time [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45] in any of the physical activity behaviors measured. Effect sizes varied widely among both the app-alone and app Web-based social networking studies. Across the app-alone studies, effect sizes were small (n=2) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37], medium (n=2) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41], and large (n=1) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40]. Similarly, the distribution of effect sizes reported among the app Web-based social networking studies ranged from small (n=2) [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] to medium (n=2) [Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] to large (n=1) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46].

Table 2 provides a summary of the intervention effects on psychosocial outcomes. The app-alone and app Web-based social networking studies overall reported mixed results in relation to psychosocial outcomes associated with physical activity. Specifically, 2 app-alone studies [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 1 app Web-based social networking study [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45] revealed no significant intervention effects on any of the assessed psychosocial outcomes. In total, 2 app-alone studies reported significant decreases in perceptions of barriers to exercising in the intervention condition; however, not in the alternative outcomes assessed (eg, perceived social support and self-efficacy) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41]. Contrastingly, 1 app Web-based social networking study reported improvements over time in all psychosocial outcomes assessed (eg, social support, physical activity self-efficacy, and enjoyment) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46].

Table 1. Summary of intervention effects on physical activity outcomes.
StudyPhysical activity (PA) outcomesEngagement
Daily stepsLight, moderate, moderate-to-vigorous physical activity (MVPA), and vigorous PASedentary behavior
App-alone studies

Arrogi et al, 2017 [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40]a[++]b

Bond et al, 2014 [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48][+]c[+]

Choi et al, 2016 [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38][-]dxe

Cowdery et al, 2015 [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39][-]

Fanning et al, 2017 [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41][+]x

Glynn et al, 2014 [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36][++]

Korinek et al, 2018 [Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50][+]

Pellegrini et al, 2015 [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49][+/−]f[-]g

Simons et al, 2018 [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42][-]x

Walsh et al, 2016 [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37][++]
App Web-based social networking studies

Al Ayubi et al, 2014 [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43][+]

Foster et al, 2010 [Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44][+]

Hurkmanns et al, 2018 [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47][-]

Pope et al, 2018 [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46][+][+][+]

Torquati, Kolbe-Alexander et al, 2018 [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45][-][-][-]x

aNot applicable.

bSignificant between-group improvement in outcome.

cSignificant within-group improvement in outcome.

dNo improvement in outcome.

eUnfavorable (low) engagement.

fMixed results; engagement.

gFavorable (high) engagement.

Table 2. Summary of intervention effects on psychosocial outcomes.
StudyPsychosocial outcomesBehavior change theories
Social supportPAa self-efficacyPA motivationBarriers to PAPA enjoymentOutcome expectationsPerceived benefits of PAPerceived PA competency
App-alone studies

Arrogi et al, 2017 [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40]bSCTc, CTd
Bond et al, 2014 [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48]
Choi et al, 2016 [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38][-]e[-][++]fSCT
Cowdery et al, 2015 [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39][-][-][-]SDTg
Fanning et al, 2017 [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41][-][+]h[-]SCT
Glynn et al, 2014 [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36]
Korinek et al, 2018 [Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]SCT
Pellegrini et al, 2015 [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]
Simons et al, 2018 [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42][-][-][-][-]ASEi
Walsh et al, 2016 [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37]COM-Bj
App Web-based social networking studies

Al Ayubi et al, 2014 [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43]SCT, TRAk
Foster et al, 2010 [Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44]
Hurkmanns et al, 2018 [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]
Pope et al, 2018 [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46][+][+][+]SCT
Torquati, Kolbe-Alexander et al, 2018 [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45][-][-]SCT, GSTl, CT

aPA: physical activity.

bNot applicable.

cSCT: Social Cognitive Theory.

dCT: Control Theory.

eNo improvement in outcome.

fSignificant between-group improvement in outcome.

gSDT: Self-Determination Theory.

hSignificant within-group improvement in outcome.

iASE: Attitude-social Influence Self-efficacy Model.

jCOM-B: The Capability, Opportunity, Motivation, Behavior framework.

kTRA: The Theory of Reasoned Action.

lGST: Goal setting Theory.

Measures of Engagement

Notably, only 4 of the 10 app-alone studies (40%) reported on app usage [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], whereas 80% (n=4) of the app Web-based social networking studies assessed engagement with intervention materials (app and Web-based social network) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43-Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Among the studies that assessed app engagement, objective measures were primarily utilized (n=6) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41-Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]. This included the use of Google Analytics to monitor app logins and duration of use (n=2) [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44], the functionality of the app to record logins (n=1) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41] or days and minutes of use (n=2) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], or monitoring of engagement with app content (eg, reading or responding to automated messages and logging in activity diary; n=2) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42]. Self-report measures of app engagement were also utilized in 2 app Web-based social networking studies [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. This included questionnaires whereby participants were asked to report frequency and duration of app use (n=1) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] or engagement with app content (eg, willingness to use app and follow instructions; n=1) [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. All studies that measured app engagement objectively (n=6) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41-Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49] monitored app usage over the duration of the intervention period. Conversely, among the 2 studies that utilized self-report measures, the questionnaires were completed at 2 time points: at mid and postintervention [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] and at postintervention and 6-month follow-up [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. Among the app Web-based social networking studies, 2 reported engagement with the existing Web-based social network, such that the number of Facebook posts generated and posts viewed was monitored [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46].

Engagement With the Intervention

Among the 4 app-alone studies that assessed engagement with the app, 1 reported that, on average, the app was used on 21 days for a cumulative total of 7.6 hours, over a 1-month intervention period [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]. The other 3 studies reported a notable decline in app engagement [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42]. Specifically, decreases were reported in the frequency and duration of app usage [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and engagement with app content (logging physical activity and reading or responding to messages) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] over 9-week [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 12-week intervention periods [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41]. Among the app Web-based social networking studies, a single study reported limited engagement with the intervention materials over a 3-month intervention period, reporting that 68.4% of participants used the app less than once a month or never and 47.5% of participants engaged with the Facebook page on only one occasion per week [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. Conversely, 2 reported increases in minutes of app usage following the provision of access to the existing Web-based social network [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44], and 1 reported sustained engagement with intervention materials (app and Facebook page; n=1) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46].

Comparison of Effective and Ineffective Interventions

As can be seen in Table 1, across all included studies, 7 of the 10 app-alone interventions (70%) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] and 3 of the 5 app Web-based social networking interventions (60%) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] were effective in improving one or more physical activity behaviors, as identified by P values and/or effect sizes. Among the effective interventions, the intervention durations were relatively short, ranging from 1 week [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40] to 14 weeks [Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]. In comparison, the ineffective interventions typically incorporated longer intervention durations, ranging from 9 weeks [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] to 3 months [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. Notably, 6 of the 10 (60%) effective interventions recruited low-active (n=2) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] or sedentary participants (n=2) [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], or documented that participants engaged in low levels of baseline physical activity (n=2) [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48]. By contrast, only 2 of the 5 (40%) ineffective interventions recruited low-active (n=1) [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] or sedentary participants (n=1) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38]. The effective interventions all exclusively targeted physical activity behaviors. The 2 app Web-based social networking interventions that were not effective [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47] both targeted the modification of physical activity in conjunction with diet quality. Across all included studies, objective measures of physical activity were predominately utilized (n=14) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], and the type of objective measure used (eg, accelerometer) was comparable among the effective and ineffective interventions. However, 2 of the 5 ineffective interventions utilized self-report measures to assess the physical activity behaviors [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42]. Both the effective (n=6) [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] and ineffective (n=4) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45] interventions were largely underpinned by behavior change theories. Among the 10 effective studies, 7 (70%) used newly designed apps [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] and 3 (30%) used commercially available apps [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Among the 5 ineffective studies, 3 (60%) used newly designed apps [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47] and 2 (40%) used a commercially designed app [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39].

In total, 2 of the effective interventions [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] assessed psychosocial outcomes, and mixed findings were reported. Specifically, the app-alone study that incorporated a newly designed app reported no changes in physical activity self-efficacy or physical activity outcome expectancies but identified a decrease in perceptions of barriers to exercising [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41]. In contrast, the app Web-based social networking study that incorporated a commercially available app reported increases in physical activity self-efficacy, physical activity enjoyment, and social support [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. In total, 4 of the ineffective studies assessed psychosocial outcomes [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45], and although 1 study identified a decrease in the lack of energy as a barrier to exercising [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38], no changes were reported in any of the alternative outcomes assessed, including social support [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45], physical activity self-efficacy [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45], physical activity enjoyment [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39], physical activity motivation [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39], perceived competency for exercising regularly [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39], and perceived benefits to exercising [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42].

Among the effective studies, 1 app-alone study [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41] and all app Web-based social networking studies (n=3) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] reported on app engagement. The app-alone study reported a decline in app usage over the 12-week intervention period [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41]. In contrast, in the app Web-based social networking studies, higher app usage following the provision of access to the Web-based social networking functionalities [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44] and sustained engagement with intervention materials (app and Facebook page) were reported [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Among the ineffective studies, 3 of the 5 studies reported on intervention engagement [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. Of these studies, all reported unfavorable intervention engagement, specifically declines in app engagement during a 9-week [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 12-week intervention period [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38], and low engagement with intervention materials (app and Facebook group) [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. Additionally, among the effective app Web-based social networking interventions, the existing social networks utilized were a public Facebook page (n=1) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] or a physical activity app that incorporated functionalities to connect with Facebook (n=2) [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44]. Among the 2 ineffective app Web-based social networking interventions, both incorporated a private Facebook group as the existing Web-based social network [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47].

Reporting of Methodological Characteristics

The reported methodological characteristics were examined to generate a methodological risk of bias score. Scores ranged from 9.5 (out of 20) to 20.5 (out of 25) in the app-alone studies (

Multimedia Appendix 5

Risk of bias based on Consolidated Standards of Reporting Trials Checklist; App-alone studies.

PDF File (Adobe PDF File), 106KBMultimedia Appendix 5) and from 8.5 (out of 20) to 18 (out of 25) in the app Web-based social networking studies (

Multimedia Appendix 6

Risk of bias based on Consolidated Standards of Reporting Trials Checklist; App Web-based social networking studies.

PDF File (Adobe PDF File), 82KB
Multimedia Appendix 6
). The app-alone and app Web-based social networking studies all fulfilled the checklist criteria for scientific background and a detailed description of the intervention. Among the randomized controlled trials (n=8), few adequately reported on the allocation concealment mechanisms (n=3) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] or blinding (n=3) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]; however, most did report on randomization procedures (n=7) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]. Notably, both the app-alone and app Web-based social networking studies rarely fulfilled the criterion detailing how the sample size was calculated (n=8) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41-Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48] or appropriately reported on the study outcomes (effect sizes; n=7) [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36-Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48].


Principal Findings

This review examined the influence of existing Web-based social networking platforms on the engagement with, and effectiveness of, mobile apps that target physical activity. Specifically, to isolate the influence of existing Web-based social networking platforms, the review provided a comparison between interventions that incorporated physical activity apps in conjunction with and without existing Web-based social networking platforms.

The review identified that physical activity mobile apps show promise in their capacity to improve physical activity behaviors. Of the included studies, 10 of the 15 interventions effectively improved one or more physical activity behaviors [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]. Specifically, 7 of the 10 app-alone studies [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] and 3 of the 5 app Web-based social networking studies [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46] reported improvements. At a surface level, these findings indicate that the app Web-based social networking interventions may be no more effective than the app-alone interventions. However, this may be attributed to methodological disparities between the app-alone and app Web-based social networking interventions rather than the presence of Web-based social networking per se. Specifically, heterogeneity in the recruited samples may have influenced physical activity outcomes and thus must be considered in the formation of accurate conclusions regarding intervention effectiveness. This is highlighted in the comparison of 2 app-alone [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] and an app Web-based social networking intervention [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47] that all targeted the modification of physical activity in overweight or obese individuals. The 2 app-alone interventions [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] both improved physical activity levels, whereas the app Web-based social networking study did not [Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]. However, both app-alone studies [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] reported low baseline levels of physical activity, which may have influenced intervention outcomes. Furthermore, the differences in the samples recruited may also be responsible for overall differences in intervention effectiveness between the app-alone and app Web-based social networking studies. Specifically, 80% (n=8) of the app-alone interventions recruited low-active (n=3) [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] or sedentary participants (n=3) [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49] or reported that participants engaged in low levels of physical activity at baseline (n=2) [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48]. Of these interventions, 75% (n=6) [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50] reported improvements in physical activity behaviors. This is consistent with previous literature documenting that physical activity interventions demonstrate greater effectiveness among low-active individuals, as there is a larger potential for improvement in behavior [Lubans DR, Morgan PJ, Tudor-Locke C. A systematic review of studies using pedometers to promote physical activity among youth. Prev Med 2009 Apr;48(4):307-315. [CrossRef] [Medline]51]. In contrast, none of the app Web-based social networking interventions incorporated recruitment criteria regarding sedentary or physical activity behaviors or reported low baseline levels of physical activity. Thus, the disparity among the samples may have influenced intervention outcomes, limiting the formation of appropriate conclusions regarding the influence of existing Web-based social networking platforms on intervention effectiveness. Future research is needed to evaluate the effectiveness of apps in conjunction with Web-based social networks in low-active or sedentary populations.

The comparability of intervention engagement between the app-alone and the app Web-based social networking interventions is also somewhat limited by the lack of reporting on engagement in the app-alone studies. This is consistent with existing reviews that have documented a lack of assessment of engagement in interventions targeting health behaviors [Schoeppe S, Alley S, van Lippevelde W, Bray NA, Williams SL, Duncan MJ, et al. Efficacy of interventions that use apps to improve diet, physical activity and sedentary behaviour: a systematic review. Int J Behav Nutr Phys Act 2016 Dec 7;13(1):127 [FREE Full text] [CrossRef] [Medline]8]. This presents a shortcoming of research to date, such that the previously limited assessment of engagement has hindered the identification of intervention components that may be associated with engagement. This review identified clear differences in the levels of engagement reported among the app-alone and app Web-based social networking studies. The app-alone studies that reported on patterns of engagement identified declines in app engagement over 9-week [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 12-week intervention periods [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41]. Of these studies, 1 reported improvement in physical activity behaviors [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41], whereas the other 2 did not [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42]. Across the app Web-based social networking studies, 1 study reported low engagement with intervention materials (app and Facebook group), and notably no improvement in physical activity outcomes [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. In contrast, all other app Web-based social networking studies reported increases in engagement following the provision of access to the existing Web-based social networking platform [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44] and sustained engagement with intervention materials (app and Facebook page) [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Among these studies, all reported improvements in physical activity behaviors [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], in line with previous evidence linking engagement with intervention effectiveness [Schoeppe S, Alley S, van Lippevelde W, Bray NA, Williams SL, Duncan MJ, et al. Efficacy of interventions that use apps to improve diet, physical activity and sedentary behaviour: a systematic review. Int J Behav Nutr Phys Act 2016 Dec 7;13(1):127 [FREE Full text] [CrossRef] [Medline]8,Poirier J, Cobb NK. Social influence as a driver of engagement in a web-based health intervention. J Med Internet Res 2012 Feb 22;14(1):e36 [FREE Full text] [CrossRef] [Medline]12]. Thus, the app-alone studies demonstrated the typically observed decline in app engagement [Choi J, Lee JH, Vittinghoff E, Fukuoka Y. mHealth physical activity intervention: a randomized pilot study in physically inactive pregnant women. Matern Child Health J 2016 May;20(5):1091-1101 [FREE Full text] [CrossRef] [Medline]38,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], whereas the app Web-based social networking studies showed increased and sustained intervention engagement [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. This review provides preliminary evidence that existing Web-based social networks may be an important component in increasing engagement with physical activity interventions.

The existing Web-based social networking platform incorporated into all the app Web-based social networking interventions was Facebook, including either a public Facebook page [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], a private Facebook group [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47], or a physical activity app that had the functionality to connect to Facebook [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44]. The existing Web-based social networks utilized a diverse range of features that primarily facilitated social interaction, social comparison, and competition. However, the heterogeneity in the features utilized, and the predominance of studies that incorporated several different features, limited the capacity to ascertain the association between specific features of Web-based social networking and app engagement. Interestingly, the findings indicated that the differential use of the Facebook platform may have influenced intervention effectiveness. The interventions incorporating a private Facebook group did not report improvements in physical activity behaviors [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47]. Of these interventions, one study [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45] reported on intervention engagement and psychosocial constructs, identifying low intervention engagement, and no changes in social support or self-efficacy. Contrastingly, the interventions that incorporated a Facebook page [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], or an app that connected with Facebook [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44] showed improvements in physical activity behaviors and resulted in increased and sustained engagement. Additionally, increases were reported in social support, self-efficacy, and physical activity enjoyment in one of these studies [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Importantly, these are all psychosocial constructs associated with facilitating physical activity behaviors [Courneya KS, Plotnikoff RC, Hotz SB, Birkett NJ. Social support and the theory of planned behavior in the exercise domain. Am J Health Behav 2000 Jul 1;24(4):300-308. [CrossRef]25], intervention engagement [Poirier J, Cobb NK. Social influence as a driver of engagement in a web-based health intervention. J Med Internet Res 2012 Feb 22;14(1):e36 [FREE Full text] [CrossRef] [Medline]12,Perski O, Blandford A, West R, Michie S. Conceptualising engagement with digital behaviour change interventions: a systematic review using principles from critical interpretive synthesis. Transl Behav Med 2017 Dec;7(2):254-267 [FREE Full text] [CrossRef] [Medline]24], and sustained behavior change [Courneya KS, Plotnikoff RC, Hotz SB, Birkett NJ. Social support and the theory of planned behavior in the exercise domain. Am J Health Behav 2000 Jul 1;24(4):300-308. [CrossRef]25]. Notably, among the interventions that produced favorable outcomes [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], participants’ existing networks were leveraged via apps that connected with Facebook [Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44], or a Facebook page [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46]. Contrastingly, the interventions that produced unfavorable outcomes [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Hurkmans E, Matthys C, Bogaerts A, Scheys L, Devloo K, Seghers J. Face-to-face versus mobile versus blended weight loss program: randomized clinical trial. JMIR Mhealth Uhealth 2018 Jan 11;6(1):e14 [FREE Full text] [CrossRef] [Medline]47] incorporated private Facebook groups that generated an artificial Web-based social network, such that participants were required to create connections with unknown others. This indicates that network dynamics may be an important underlying determinant of the influence of Web-based social networks on intervention outcomes.

Implications for Future Research

This review suggests that the way in which Web-based social networking platforms are utilized must be considered in the development of interventions as it has important implications for intervention effectiveness. This highlights a gap in the literature, such that little guidance exists in relation to optimally harnessing Web-based social networking platforms in behavior change interventions. Future research must endeavor to identify specific features of Web-based social networking platforms that are associated with intervention engagement, to ascertain how best to incorporate Web-based social networking into health interventions. However, this will require a greater understanding of the mechanisms (eg, social support) underlying the influence of Web-based social networking on health behaviors, to elucidate how best to leverage specific features of Web-based social networking platforms in health interventions. In addition, Web-based social networking is evolving rapidly, and, thus, an understanding of the underlying mechanisms will be advantageous in identifying how to optimally leverage a diverse range of social networking platforms in future interventions.

The present review further ascertained disparities among the designs and quality of app-alone and app Web-based social networking studies. The app-alone interventions were predominately randomized controlled trials; by contrast, the app Web-based social networking studies were largely pre-post within-subjects designs. Thus, future research must endeavor to utilize study designs of a higher standard (ie, randomized controlled trials) to increase the quality of evidence pertaining to the effectiveness of interventions incorporating physical activity apps in conjunction with Web-based social networking. Furthermore, the app-alone and app Web-based social networking studies incorporated predominately short intervention durations, and across all studies in the review, only 3 included follow-up assessments, at 1-week postintervention [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], 3 months [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42], and 6 months postintervention [Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45]. The dearth of evidence regarding the long-term efficacy of mobile apps is frequently documented as an important shortcoming. Evaluating the long-term effectiveness of mobile apps is imperative, as sustained engagement in physical activity behavior is required to attain the associated health benefits [Jepson RG, Harris FM, Platt S, Tannahill C. The effectiveness of interventions to change six health behaviours: a review of reviews. BMC Public Health 2010 Sep 8;10:538 [FREE Full text] [CrossRef] [Medline]16].

The review identified several features of the interventions that may be important in guiding the design of future interventions. Specifically, interventions that were effective targeted exclusively the modification of physical activity behaviors. This is consistent with previous research identifying that single behavior change interventions targeting physical activity are more effective than interventions that target multiple behaviors (eg, physical activity and dietary behavior) [Sweet SN, Fortier MS. Improving physical activity and dietary behaviours with single or multiple health behaviour interventions? A synthesis of meta-analyses and reviews. Int J Environ Res Public Health 2010 Dec;7(4):1720-1743 [FREE Full text] [CrossRef] [Medline]52,Prochaska JJ, Prochaska JO. A review of multiple health behavior change interventions for primary prevention. Am J Lifestyle Med 2011 May;5(3):- [FREE Full text] [CrossRef] [Medline]53]. Although interventions that target multiple health behaviors simultaneously have the potential to maximize health benefits, evidence suggests that the modification of one behavior will enhance intervention outcomes [Sweet SN, Fortier MS. Improving physical activity and dietary behaviours with single or multiple health behaviour interventions? A synthesis of meta-analyses and reviews. Int J Environ Res Public Health 2010 Dec;7(4):1720-1743 [FREE Full text] [CrossRef] [Medline]52,Prochaska JJ, Prochaska JO. A review of multiple health behavior change interventions for primary prevention. Am J Lifestyle Med 2011 May;5(3):- [FREE Full text] [CrossRef] [Medline]53]. Furthermore, the interventions that were effective incorporated objective measures of physical activity [Glynn LG, Hayes PS, Casey M, Glynn F, Alvarez-Iglesias A, Newell J, et al. Effectiveness of a smartphone application to promote physical activity in primary care: the SMART MOVE randomised controlled trial. Br J Gen Pract 2014 Jul;64(624):e384-e391 [FREE Full text] [CrossRef] [Medline]36,Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37,Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Foster D, Linehan C, Kirman B, Lawson S, James G. Motivating Physical Activity at Work: Using Persuasive Social Media for Competitive Step Counting. In: Proceedings of the 14th International Academic MindTrek Conference: Envisioning Future Media Environments. 2010 Presented at: MindTrek'10; October 6-8, 2010; Tampere, Finland p. 111-116. [CrossRef]44,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48-Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]. Interestingly, the 2 studies that incorporated a self-report measure of physical activity did not report an increase in physical activity over intervention periods of 9 [Simons D, de Bourdeaudhuij I, Clarys P, de Cocker K, Vandelanotte C, Deforche B. Effect and process evaluation of a smartphone app to promote an active lifestyle in lower educated working young adults: cluster randomized controlled trial. JMIR Mhealth Uhealth 2018 Aug 24;6(8):e10003 [FREE Full text] [CrossRef] [Medline]42] and 12 weeks [Cowdery J, Majeske P, Frank R, Brown D. Exergame apps and physical activity: the results of the ZOMBIE trial. Am J Health Educ 2015 Jul 6;46(4):216-222 [FREE Full text] [CrossRef]39]. It is possible that self-report measures as opposed to objective measures such as accelerometers afford lower sensitivity to detect changes in physical activity behaviors over short intervention periods [Shephard RJ. Limits to the measurement of habitual physical activity by questionnaires. Br J Sports Med 2003 Jun;37(3):197-206; discussion 206 [FREE Full text] [CrossRef] [Medline]54]. Indeed, a previous review has demonstrated that 69% of studies that incorporated self-report measures, as opposed to 20% of studies that measured physical activity objectively, found no effect on physical activity [Covolo L, Ceretti E, Moneda M, Castaldi S, Gelatti U. Does evidence support the use of mobile phone apps as a driver for promoting healthy lifestyles from a public health perspective? A systematic review of randomized control trials. Patient Educ Couns 2017 Dec;100(12):2231-2243. [CrossRef] [Medline]9]. In addition, in this review, comparatively, there was no difference in the effectiveness of interventions that used a newly designed app as opposed to a commercially available app. Despite this, the interventions largely utilized newly designed apps. This is problematic as commercially available apps are ubiquitous and highly accessible to the general public; however, evidence of their effectiveness is lacking [Bondaronek P, Alkhaldi G, Slee A, Hamilton FL, Murray E. Quality of publicly available physical activity apps: review and content analysis. JMIR Mhealth Uhealth 2018 Mar 21;6(3):e53 [FREE Full text] [CrossRef] [Medline]19,Conroy DE, Yang CH, Maher JP. Behavior change techniques in top-ranked mobile apps for physical activity. Am J Prev Med 2014 Jun;46(6):649-652. [CrossRef] [Medline]20,Cowan LT, van Wagenen SA, Brown BA, Hedin RJ, Seino-Stephan Y, Hall PC, et al. Apps of steel: are exercise apps providing consumers with realistic expectations?: a content analysis of exercise apps for presence of behavior change theory. Health Educ Behav 2013 Apr;40(2):133-139. [CrossRef] [Medline]22]. Thus, future research should evaluate the effectiveness of commercially available physical activity mobile apps.

Overall, the mobile apps were effective in increasing physical activity in a diverse range of population samples, including inactive [Fanning J, Roberts S, Hillman CH, Mullen SP, Ritterband L, McAuley E. A smartphone 'app'-delivered randomized factorial trial targeting physical activity in adults. J Behav Med 2017 Oct;40(5):712-729. [CrossRef] [Medline]41,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], sedentary [Arrogi A, Bogaerts A, Seghers J, Devloo K, Abeele VV, Geurts L, et al. Evaluation of stAPP: a smartphone-based intervention to reduce prolonged sitting among Belgian adults. Health Promot Int 2019 Feb 1;34(1):16-27. [CrossRef] [Medline]40,Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49], obese or overweight individuals [Bond DS, Thomas JG, Raynor HA, Moon J, Sieling J, Trautvetter J, et al. B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial. PLoS One 2014;9(6):e100821 [FREE Full text] [CrossRef] [Medline]48,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50], breast cancer survivors [Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46], and individuals diagnosed with type 2 diabetes [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]. However, all studies exclusively targeted adults, ranging from 20 [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37] to 53 years [Pellegrini CA, Hoffman SA, Daly ER, Murillo M, Iakovlev G, Spring B. Acceptability of smartphone technology to interrupt sedentary time in adults with diabetes. Transl Behav Med 2015 Sep;5(3):307-314 [FREE Full text] [CrossRef] [Medline]49]. Thus, future research must endeavor to evaluate the applicability of physical activity mobile apps in conjunction with existing Web-based social networks in alternative age groups, in particular among adolescents, a highly inactive population subgroup [World Health Organisation. 2018. Physical Activity: Key Facts   URL: http://www.who.int/news-room/fact-sheets/detail/physical-activity [accessed 2018-07-02] [WebCite Cache]55], and among the highest users of existing Web-based social networking platforms [Anderson M, Jiang J. Pew Research Center. 2018. Teens, Social Media & Technology   URL: http://www.pewinternet.org/2018/05/31/teens-social-media-technology-2018/ [accessed 2018-07-05] [WebCite Cache]56]. This will ensure that mobile apps are an appropriate medium to disseminate physical activity interventions that are scalable, owing to their applicability to the population broadly.

This review also has important implications for guiding the development of an appropriate theoretical foundation to inform future physical activity mobile apps. The included interventions incorporated mobile apps predominately underpinned by behavior change theory [Walsh JC, Corbett T, Hogan M, Duggan J, McNamara A. An mhealth intervention using a smartphone app to increase walking behavior in young adults: a pilot study. JMIR Mhealth Uhealth 2016 Sep 22;4(3):e109 [FREE Full text] [CrossRef] [Medline]37-Al Ayubi SU, Parmanto B, Branch R, Ding D. A persuasive and social mhealth application for physical activity: a usability and feasibility study. JMIR Mhealth Uhealth 2014 May 22;2(2):e25 [FREE Full text] [CrossRef] [Medline]43,Torquati L, Kolbe-Alexander T, Pavey T, Leveritt M. Changing diet and physical activity in nurses: a pilot study and process evaluation highlighting challenges in workplace health promotion. J Nutr Educ Behav 2018;50(10):1015-1025. [CrossRef] [Medline]45,Pope Z, Lee JE, Zeng N, Lee HY, Gao Z. Feasibility of smartphone application and social media intervention on breast cancer survivors' health outcomes. Transl Behav Med 2019 Dec 1;9(1):11-22. [CrossRef] [Medline]46,Korinek EV, Phatak SS, Martin CA, Freigoun MT, Rivera DE, Adams MA, et al. Adaptive step goals and rewards: a longitudinal growth model of daily steps for a smartphone-based walking intervention. J Behav Med 2018 Dec;41(1):74-86. [CrossRef] [Medline]50]. This suggests that there was no association between mobile app effectiveness and the utilization of any one particular theory. Additionally, across the included studies a diverse range of behavior change theories were utilized, limiting the formation of conclusions regarding the most effective theory to guide the development of physical activity mobile apps. This is consistent with previous research examining the content of physical activity mobile apps that has documented challenges ascertaining the theory or combination of theories associated with physical activity mobile app effectiveness [Stuckey MI, Carter SW, Knight E. The role of smartphones in encouraging physical activity in adults. Int J Gen Med 2017;10:293-303 [FREE Full text] [CrossRef] [Medline]23].

The physical activity apps examined in this review incorporated a diverse range of features. The most common among these were monitoring or tracking of behavior, feedback, information or education related to physical activity, goal setting, and providing reinforcements (eg, points). Much of the previous research that has examined the content of physical activity apps has utilized a taxonomy developed by Abraham and Michie [Abraham C, Michie S. A taxonomy of behavior change techniques used in interventions. Health Psychol 2008 May;27(3):379-387. [CrossRef] [Medline]57] that functions to isolate the presence of behavior change techniques common to many behavior change theories. This research has identified that feedback, self-monitoring, and goal setting are features frequently integrated into apps, in line with findings by this review [Bondaronek P, Alkhaldi G, Slee A, Hamilton FL, Murray E. Quality of publicly available physical activity apps: review and content analysis. JMIR Mhealth Uhealth 2018 Mar 21;6(3):e53 [FREE Full text] [CrossRef] [Medline]19,Middelweerd A, Mollee JS, van der Wal CN, Brug J, Te Velde SJ. Apps to promote physical activity among adults: a review and content analysis. Int J Behav Nutr Phys Act 2014 Jul 25;11:97 [FREE Full text] [CrossRef] [Medline]58,Simões P, Silva AG, Amaral J, Queirós A, Rocha NP, Rodrigues M. Features, behavioral change techniques, and quality of the most popular mobile apps to measure physical activity: systematic search in app stores. JMIR Mhealth Uhealth 2018 Oct 26;6(10):e11281 [FREE Full text] [CrossRef] [Medline]59]. Notably, Abraham and Michie [Michie S, Abraham C, Whittington C, McAteer J, Gupta S. Effective techniques in healthy eating and physical activity interventions: a meta-regression. Health Psychol 2009 Nov;28(6):690-701. [CrossRef] [Medline]60] highlight that these features are also commonly associated with effectively modifying physical activity behavior. This may have underpinned the capacity of the majority of the apps in the current review to improve physical activity behavior. However, the specific number or combination of features that may have a greater influence on the effectiveness of physical activity apps is currently unknown, and thus requires future examination.

Limitations

To our knowledge, this is the first review to isolate the influence of existing Web-based social networking platforms by providing a comparison between interventions that incorporate mobile physical activity apps in conjunction with and without existing Web-based social networking platforms. Despite the novel nature of this review, several limitations must be noted. First, to date, there are only a small number of studies that have incorporated physical activity mobile apps in conjunction with an existing Web-based social networking platform. Additionally, owing to the heterogeneity of the identified studies in relation to the target population, intervention, study design, and outcomes measured, the results could not be validly pooled, precluding the ability to conduct a meta-analysis, and, thus, form definitive conclusions regarding the influence of Web-based social networks. Second, all interventions incorporated apps that targeted aerobic activity, and, thus, the findings may not generalize to apps aimed at other types of physical activity such as strength training. Future research should endeavor to examine apps targeted at all forms of physical activity. Third, among the included studies the methodological risk of bias varied, with some studies receiving low scores, limiting the trust that may be placed in their findings. Finally, there is a possibility of publication bias as the search did not incorporate gray literature or non-English publications.

Conclusions

In conclusion, the unprecedented growth in physical activity mobile apps presents an innovative medium to disseminate scalable interventions to increase levels of physical activity worldwide. However, previous literature has consistently documented that the effectiveness of mobile apps is limited by low levels of engagement. The popularity, reach, and engagement afforded by existing Web-based social networking platforms provides an unparalleled opportunity to serve as an adjunct to mobile apps to augment engagement, and ultimately effectiveness. Thus, this review aimed to provide insight into the influence of existing Web-based social networks by providing a comparison between interventions that incorporated mobile apps in conjunction with and without existing Web-based social networking platforms. Both the interventions incorporating physical activity apps in conjunction with and without existing Web-based social networking platforms demonstrated effectiveness in improving physical activity behaviors. Notably, however, interventions that incorporated existing Web-based social networking platforms achieved higher levels of engagement than those that did not. This provides preliminary evidence that existing Web-based social networking platforms may be fundamental in overcoming the previously documented low engagement associated with physical activity mobile apps. This is of particular importance as greater app engagement is associated with increased exposure to intervention content, and ultimately an enhanced capacity of the app to effectively improve physical activity behavior. Thus, existing Web-based social networks must be further evaluated by conducting rigorously designed randomized controlled trials. Importantly, future research must endeavor to provide a greater understanding of the mechanisms underlying the influence of Web-based social networking on physical activity behaviors, to ascertain how best to leverage specific features of Web-based social networking platforms. This review makes an important contribution to guiding future research, by providing an initial insight into mobile apps and existing Web-based social networking platforms, imperative to improving the development of interventions targeted at increasing physical activity levels.

Acknowledgments

The authors thank Nikki May for providing guidance in the development of the search strategy, and Marcela Radunz, Nepheli Beos, and Chloe Craig for their assistance with the screening process and the study quality assessments.

Conflicts of Interest

None declared.

Multimedia Appendix 1

App-alone search strategy.

PDF File (Adobe PDF File), 48KB

Multimedia Appendix 2

App Web-based social networking search strategy.

PDF File (Adobe PDF File), 46KB

Multimedia Appendix 3

Characteristics of app-alone studies.

PDF File (Adobe PDF File), 122KB

Multimedia Appendix 4

Characteristics of app Web-based social networking studies.

PDF File (Adobe PDF File), 88KB

Multimedia Appendix 5

Risk of bias based on Consolidated Standards of Reporting Trials Checklist; App-alone studies.

PDF File (Adobe PDF File), 106KB

Multimedia Appendix 6

Risk of bias based on Consolidated Standards of Reporting Trials Checklist; App Web-based social networking studies.

PDF File (Adobe PDF File), 82KB

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BMI: Body Mass Index
CONSORT: Consolidated Standards of Reporting Trials
IPAQ: International Physical Activity Questionnaire
MVPA: moderate-to-vigorous physical activity
PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses


Edited by G Eysenbach; submitted 04.11.18; peer-reviewed by C Bedard, S Edney, B Chaudhry, L Grepo; comments to author 21.03.19; revised version received 13.05.19; accepted 10.06.19; published 16.08.19

Copyright

©Jasmine Maria Petersen, Ivanka Prichard, Eva Kemps. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 16.08.2019.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.


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