A Social Group-Based Information-Motivation-Behavior Skill Intervention to Promote Acceptability and Adoption of Wearable Activity Trackers Among Middle-Aged and Older Adults: Cluster Randomized Controlled Trial

Background Wearable activity trackers offer potential to optimize behavior and support self-management. To assist older adults in benefiting from mobile technologies, theory-driven deployment strategies are needed to overcome personal, technological, and sociocontextual barriers in technology adoption. Objective To test the effectiveness of a social group–based strategy to improve the acceptability and adoption of activity trackers by middle-aged and older adults. Methods A cluster randomized controlled trial was conducted among 13 groups of middle-aged and older adults (≥45 years) performing group dancing (ie, square dancing) as a form of exercise in Guangzhou from November 2017 to October 2018. These dancing groups were randomized 1:1 into two arms, and both received wrist-worn activity trackers and instructions at the baseline face-to-face assessment. Based on the Information-Motivation-Behavior Skill framework, the intervention arm was also given a tutorial on the purpose of exercise monitoring (Information), encouraged to participate in exercise and share their exercise records with their dancing peers (Motivation), and were further assisted with the use of the activity tracker (Behavior Skill). We examined two process outcomes: acceptability evaluated by a 14-item questionnaire, and adoption assessed by the uploaded step count data. Intention-to-treat analysis was applied, with the treatment effects estimated by multilevel models. Results All dancing groups were followed up for the postintervention reassessment, with 61/69 (88%) participants of the intervention arm (7 groups) and 56/80 (70%) participants of the control arm (6 groups). Participants’ sociodemographic characteristics (mean age 62 years, retired) and health status were comparable between the two arms, except the intervention arm had fewer female participants and lower cognitive test scores. Our intervention significantly increased the participants’ overall acceptability by 6.8 points (95% CI 2.2-11.4), mainly driven by promoted motivation (adjusted group difference 2.0, 95% CI 0.5-3.6), increased usefulness (adjusted group difference 2.5, 95% CI 0.9-4.1), and better perceived ease of use (adjusted group difference 1.2, 95% CI 0.1-2.4), whereas enjoyment and comfort were not increased (adjusted group difference 0.9, 95% CI –0.4-2.3). Higher adoption was also observed among participants in the intervention arm, who were twice as likely to have valid daily step account data than their controlled counterparts (adjusted incidence relative risk [IRR]=2.0, 95% CI 1.2-3.3). The average daily step counts (7803 vs 5653 steps/day for the intervention and control, respectively) were similar between the two arms (adjusted IRR=1.4, 95% CI 0.7-2.5). Conclusions Our social group–based deployment strategy incorporating information, motivation, and behavior skill components effectively promoted acceptability and adoption of activity trackers among community-dwelling middle-aged and older adults. Future studies are needed to examine the long-term effectiveness and apply this social engagement strategy in other group settings or meeting places. Trial Registration Chinese Clinical Trial Registry ChiCTR-IOC-17013185; https://tinyurl.com/vedwc7h.

Is this a full powered effectiveness trial or a pilot/feasibility trial? * Manuscript tracking number * If this is a JMIR submission, please provide the manuscript tracking number under "other" (The ms tracking number can be found in the submission acknowledgement email, or when you login as author in JMIR. If the paper is already published in JMIR, then the ms tracking number is the four-digit number at the end of the DOI, to be found at the 1a-i) Identify the mode of delivery in the title Identify the mode of delivery. Preferably use "web-based" and/or "mobile" and/or "electronic game" in the title. Avoid ambiguous terms like "online", "virtual", "interactive". Use "Internet-based" only if Intervention includes non-web-based Internet components (e.g. email), use "computer-based" or "electronic" only if offline products are used. Use "virtual" only in the context of "virtual reality" (3-D worlds). Use "online" only in the context of "online support groups". Complement or substitute product names with broader terms for the class of products (such as "mobile" or "smart phone" instead of "iphone"), especially if the application runs on different platforms.
Does your paper address subitem 1a-i? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Yes, we specify in our title the mode of delivery as "Wearable Activity Trackers".
subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 1a-ii) Non-web-based components or important cointerventions in title Mention non-web-based components or important co-interventions in title, if any (e.g., "with telephone support").
Does your paper address subitem 1a-ii?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Yes, our title includes non-web-based components as "Social-Group Based Deployment Intervention".
1a-iii) Primary condition or target group in the title Mention primary condition or target group in the title, if any (e.g., "for children with Type I Diabetes") Example: A Web-based and Mobile Intervention with Telephone Support for Children with Type I Diabetes: Randomized Controlled Trial Does your paper address subitem 1a-iii? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Yes, we highlight our target group as "Mid and older-Aged Adults" in the title. Does your paper address subitem 1b-i? * Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Yes, we state in the methods section of the abstract as " These dancing groups were randomized 1:1 into two arms, and both received wrist-worn activity trackers and instructions at the baseline face-to-face assessment. Based on the Information-Motivation-Behavior Skill framework, the intervention arm was in addition given a tutorial on the purpose of exercise monitoring (Information), encouraged to compete in exercise and share exercise records with their dancing peers (Motivation), and further assisted with the use of activity tracker (Behavior Skill)." subitem not at all important 1 2 3 4 5 essential 1b-ii) Level of human involvement in the METHODS section of the ABSTRACT Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any). (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) Does your paper address subitem 1b-ii?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Yes, we specify the level of human involvement in the methods section of the abstract as "Based on the Information-Motivation-Behavior Skill framework, the intervention arm was in addition given a tutorial on the purpose of exercise monitoring (Information), encouraged to compete in exercise and share exercise records with their dancing peers (Motivation), and further assisted with the use of activity tracker (Behavior Skill)." subitem not at all important Does your paper address subitem 1b-iii?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We state our methods part as "These dancing groups were randomized 1:1 into two arms, which both received wrist-worn activity trackers and instructions at the baseline face-to-face assessment." 1b-iv) RESULTS section in abstract must contain use data Report number of participants enrolled/assessed in each group, the use/uptake of the intervention (e.g., attrition/adherence metrics, use over time, number of logins etc.), in addition to primary/secondary outcomes. (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 1b-iv?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We address this point in the result section of the abstract as "All dancing groups were followed up for the post-intervention reassessment, with 61 out of 69 participants (88%) of the intervention arm (seven groups) and 56 out of 80 participants (70%) of the control arm (six group). Participants' sociodemographic characteristics (mean age 62 years, retired) and health status were comparable between two arms, except for the intervention arm had fewer female participants and lower cognitive test scores. Our intervention significantly increased participants' overall acceptability by 6.8 points (95% CI 2.2 to 11.4), mainly driven by promoted motivation (adjusted group difference 2.0, 95% CI: 0.5 to 3.6), increased usefulness (adjusted group difference 2.5, 95% CI: 0.9 to 4.1) and better perceived ease-of-use (adjusted group difference 1.2, 95%CI 0.1 to 2.4); but not enjoyment and comfort (adjusted group difference 0.9, 95% CI -0.4 to 2.3). Higher adoption was also showed among participants of the intervention arm, who were twice more likely to have valid daily step account data than their controlled counterparts ( Does your paper address CONSORT subitem 2b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Our specific objective and hypothesis were presented in the last paragraph of Introduction. 3b) Important changes to methods after trial commencement (such as eligibility criteria), with reasons Does your paper address CONSORT subitem 3a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We introduced our trial design as "This phase 1 report covers the trial conducted between November 2017 and October 2018, consisting of seven-month recruitment and baseline assessment, three-month intervention, and the post-intervention reassessment. While phase 2 focuses on health outcomes, this interim study prioritizes implementation outcomes. The study was carried out in Guangzhou, the capital city of Guangdong province, China. The trial was developed guided by the CONSORT-EHEALTH Checklist and CONSORT-Checklist for reporting a cluster randomized controlled trial" The allocation ratio was stated in "Random Allocation" section as " All random allocation was done at the cluster level, namely, by the square-dancing groups. After the recruitment of all eligible participants, a statistician otherwise not associated with the project allocated participants by their squaredancing groups equally into two arms (1:1), following a simple randomization process. Although the participants were aware of the interventional nature of the study, they were blinded to their allocation status. Outcome assessors were blinded to the group assignments and were different from researchers who conducted and monitored the interventions." Does your paper address CONSORT subitem 3b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study There was no important changes to the methods after trial commencement.
subitem not at all important 1 2 3 4 5 essential 4a) Eligibility criteria for participants 3b-i) Bug fixes, Downtimes, Content Changes Bug fixes, Downtimes, Content Changes: ehealth systems are often dynamic systems. A description of changes to methods therefore also includes important changes made on the intervention or comparator during the trial (e.g., major bug fixes or changes in the functionality or content) (5-iii) and other "unexpected events" that may have influenced study design such as staff changes, system failures/downtimes, etc. [2].
Does your paper address subitem 3b-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study

您的回答
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 4a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Participants' eligibility was described as " Square-dancing groups regularly practicing in those selected places were used as the sampling frame. Dancing groups were eligible for the current study if the dancing style was not ballroom dance, and the group total size was no less than twenty with more than half of the dancers aged 45 years and older. Square dancers of the eligible dancing group, who were 1) communityresidents of Guangzhou; 2) regularly practiced square dancing at least once per week in the past 12 months; 3) aged 45 years and older; and 4) agreed to participate in our study if recruited. Participants were excluded if they 1) had serious and uncontrolled diseases related to heart, brain, lung, liver and kidney or any acute complications; and 2) had no smartphone devices (as the data recorded by the wearable activity trackers can only be uploaded to the cloud via the paired smart-phone devices)".

4a-i) Computer / Internet literacy
Computer / Internet literacy is often an implicit "de facto" eligibility criterion -this should be explicitly clarified.
Does your paper address subitem 4a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答 subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 4a-ii) Open vs. closed, web-based vs. face-to-face assessments: Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. offline), e.g., from an open access website or from a clinic, and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant. In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email confirmation, phone calls) were used to detect/prevent these.
Does your paper address subitem 4a-ii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described our recruitment and assessments strategies as "Major public squares and parks of three old districts of Guangzhou, namely Yuexiu, Haizhu and Liwan, were identified via online map (i.e. Baidu map), considering their land area and visitor flow, and sit in residential areas. Using a restricted randomizing sampling approach, eight squares and parks per district were chosen at random. We recruited participant in the selected square and parks, using advertisements and flyers." and " Participants were initially screened for eligibility via onsite interviews, and eligible participants were invited for health checkups at the local community health centers on a scheduled date." 4a-iii) Information giving during recruitment Information given during recruitment. Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results.
4b) Settings and locations where the data were collected Does your paper address subitem 4a-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Informed consent was obtained from our participants, as stated in the article "All participants read and signed the written informed consent approved by the Institutional Review Board (No. L2016-004) of the School of Public Health of Sun Yat-sen University." Does your paper address CONSORT subitem 4b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We address the data collection method as "Control variables were collected during the recruitment and baseline health checkup prior to the intervention by investigators and clinical staff who were blinded to the intervention assignment. During the intervention, data on participants' daily physical activity level (e.g. step counts) were automatically recorded and uploaded by the wearable activity trackers and their paired smart phones, as indicators for adoption. At the post-intervention assessment, participants evaluated their satisfaction with the activity trackers by the 14-item questionnaire, as an indicator for acceptability." subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 5) The interventions for each group with sufficient details to allow replication, including how and when they were actually administered 4b-i) Report if outcomes were (self-)assessed through online questionnaires Clearly report if outcomes were (self-)assessed through online questionnaires (as common in web-based trials) or otherwise.
Does your paper address subitem 4b-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Data collection methods were described as the answer above. Does your paper address subitem 5-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We provided detailed information on our intervention components in the Intervention & Procedures section of the Methods.

5-ii) Describe the history/development process
Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results.
Does your paper address subitem 5-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study

5-iii) Revisions and updating
Revisions and updating. Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial. Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).
Does your paper address subitem 5-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study

5-iv) Quality assurance methods
Provide information on quality assurance methods to ensure accuracy and quality of information provided [1], if applicable.
Does your paper address subitem 5-iv?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答 subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 5-v) Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing flowcharts of the algorithms used Ensure replicability by publishing the source code, and/or providing screenshots/screencapture video, and/or providing flowcharts of the algorithms used. Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scientific reporting.
Does your paper address subitem 5-v?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答

5-vi) Digital preservation
Digital preservation: Provide the URL of the application, but as the intervention is likely to change or disappear over the course of the years; also make sure the intervention is archived (Internet Archive, webcitation.org, and/or publishing the source code or screenshots/videos alongside the article). As pages behind login screens cannot be archived, consider creating demo pages which are accessible without login.
Does your paper address subitem 5-vi?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study

5-vii) Access
Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of specific group. If known, describe how participants obtained "access to the platform and Internet" [1]. To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi).
Does your paper address subitem 5-vii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described the use of the wearable activity trackers in our study as "Both the intervention and control arms were equipped with wrist-worn activity trackers free of charge at the baseline assessment." 5-viii) Mode of delivery, features/functionalities/components of the intervention and comparator, and the theoretical framework subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 5-viii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We provided detailed information on the mode of delivery, the theorybased intervention components in the Intervention & Procedures section of the Method, and in Figure 1.

5-ix) Describe use parameters
Describe use parameters (e.g., intended "doses" and optimal timing for use). Clarify what instructions or recommendations were given to the user, e.g., regarding timing, frequency, heaviness of use, if any, or was the intervention used ad libitum.
Does your paper address subitem 5-ix?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Information on use parameters were given in the Intervention & Procedures section of Methods, for instance as " Participants at both arms received 30-minute demonstration on the core functions of these activity trackers (e.g. how to wear, read the displays and charge the trackers), and were instructed to wear them over the entire day until going to bed." subitem not at all important

5-x) Clarify the level of human involvement
Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered". It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
Does your paper address subitem 5-x?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We specified the level of human involvement for each component we used in our intervention. For instance, for the set-up and troubleshooting of wearable activity trackers we stated "One project facilitator was assigned to assist one dancing group, who conducted the initial set-ups, provided troubleshooting, and monitored participants' uploaded PA data via the managerial accounts." 5-xi) Report any prompts/reminders used Report any prompts/reminders used: Clarify if there were prompts (letters, emails, phone calls, SMS) to use the application, what triggered them, frequency etc. It may be necessary to distinguish between the level of prompts/reminders required for the trial, and the level of prompts/reminders for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 5-xi? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study For the intervention arm, we specified our reminders as "Six booster educational voice-messages on PA related topics such as warming up & relaxing exercises were delivered twice a month via participants' WeChat groups (defined below). These messages consisted of a one-minute voice message, along with the corresponding transcript and illustrations."

5-xii) Describe any co-interventions (incl. training/support)
Describe any co-interventions (incl. training/support): Clearly state any interventions that are provided in addition to the targeted eHealth intervention, as ehealth intervention may not be designed as stand-alone intervention. This includes training sessions and support [1]. It may be necessary to distinguish between the level of training required for the trial, and the level of training for a routine application outside of a RCT setting (discuss under item 21 -generalizability. Does your paper address subitem 5-xii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described co-intervention for both arms as "Participants at both arms received 30-minute demonstration on the core functions of these activity trackers (e.g. how to wear, read the displays and charge the trackers), and were instructed to wear them over the entire day until going to bed." Additional co-intervention was only provided to the intervention arm based on the information-motivation-behavior skill components.
6a) Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed Does your paper address CONSORT subitem 6a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We defined our outcomes as "The current interim study focused on the process outcomes, namely, the acceptability and adoption of wearable activity trackers. Acceptability was defined as users' subjective perception and experiences, and was evaluated by a 14-item users' feedback questionnaire (Multimedia Appendix 1), adapted from previous usability and acceptability studies. Rated on a five-point Likert scale from 1'strongly disagree' to 5 'strongly agree', this questionnaire assessed users' acceptability in four main domains: enjoyment & comfort (three items, range 3~15; Cronbach alpha=.85), motivation to use (four items, range 4~20; Cronbach alpha=.83), usefulness (four items, range 4~20; Cronbach alpha=.89), and perceived ease-of-use (three items, range 3~15; Cronbach alpha=.76). A total score was calculated to indicate users' overall experience (Cronbach alpha=.93, range 14~70). Adoption was defined as users' interaction and usage behavior, and was evaluated objectively via the uploaded step count data in two ways: 1) the percentage of days having valid step records over individuals' follow-up days (average 90.7 days), and 2) the average daily step counts per person of these valid step records. Daily step counts less than the 5th percentile of the study sample's daily step counts (i.e. 1,311 steps per day) were treated as invalid records and were removed, as those steps might represent non-wear and inappropriate use of the activity trackers." subitem not at all important Does your paper address subitem 6a-i?
Copy and paste relevant sections from manuscript text 您的回答 6a-ii) Describe whether and how "use" (including intensity of use/dosage) was defined/measured/monitored Describe whether and how "use" (including intensity of use/dosage) was defined/measured/monitored (logins, logfile analysis, etc.). Use/adoption metrics are important process outcomes that should be reported in any ehealth trial.
Does your paper address subitem 6a-ii?
Copy and paste relevant sections from manuscript text We described the use monitoring as "Adoption was defined as users' interaction and usage behavior, and was evaluated objectively via the uploaded step count data in two ways: 1) the percentage of days having valid step records over individuals' follow-up days (average 90.7 days), and 2) the average daily step counts per person of these valid step records. Daily step counts less than the 5th percentile of the study sample's daily step counts (i.e. 1,311 steps per day) were treated as invalid records and were removed, as those steps might represent nonwear and inappropriate use of the activity trackers." subitem not at all important 1 2 3 4 5 essential 6b) Any changes to trial outcomes after the trial commenced, with reasons 7a) How sample size was determined NPT: When applicable, details of whether and how the clustering by care provides or centers was addressed 6a-iii) Describe whether, how, and when qualitative feedback from participants was obtained Describe whether, how, and when qualitative feedback from participants was obtained (e.g., through emails, feedback forms, interviews, focus groups).
Does your paper address subitem 6a-iii?
Copy and paste relevant sections from manuscript text We stated in the Data collection section: "To further explore users' experiences with the activity trackers, participants' qualitative feedbacks were also collected by the group facilitators. In reference to the acceptability questionnaire, participants were encouraged to elaborate their self-monitoring experiences regarding enjoyment & comfort, motivation to use, usefulness, and ease-of-use. Their feedbacks were analyzed in a deductive manner to extract information concerning the barriers and facilitators of each acceptability domain. A formal coding process was not applied." Does your paper address CONSORT subitem 6b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study NOT applicable.
subitem not at all important 1 2 3 4 5 essential 7b) When applicable, explanation of any interim analyses and stopping guidelines 7a-i) Describe whether and how expected attrition was taken into account when calculating the sample size Describe whether and how expected attrition was taken into account when calculating the sample size.
Does your paper address subitem 7a-i?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study The sample size calculation was described as "The main study's sample size was calculated based on changes in physical activity levels. It was calculated that 12 square dancing groups with an average of 15 participants per arm would have 85% power to detect an increase in physical activity from 1302 to 1500 MET-min per week, assuming an intracluster correlation of 0.05 and a 5% type I error. To further account for a 20% attrition ratio, 24 dancing groups across three districts were needed to fulfill a total sample size of 440 individual participants." Does your paper address CONSORT subitem 7b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 8a) Method used to generate the random allocation sequence NPT: When applicable, how care providers were allocated to each trial group 8b) Type of randomisation; details of any restriction (such as blocking and block size) 9) Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned Does your paper address CONSORT subitem 8a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We used a simple randomization process to generate the random allocation sequence, as described in the Random Allocation section "All random allocation was done at the cluster level, namely, by the squaredancing groups. After the recruitment of all eligible participants, a statistician otherwise not associated with the project allocated participants by their square-dancing groups equally into two arms (1:1), following a simple randomization process." Does your paper address CONSORT subitem 8b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We used a simple randomization process to generate the random allocation sequence, without restriction. 10) Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions 11a) If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how NPT: Whether or not administering co-interventions were blinded to group assignment Does your paper address CONSORT subitem 9? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described the allocation concealment as "Although the participants were aware of the interventional nature of the study, they were blinded to their allocation status. Outcome assessors were blinded to the group assignments and were different from researchers who conducted and monitored the interventions." Does your paper address CONSORT subitem 10? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We stated in the Methods: "After the recruitment of all eligible participants, a statistician otherwise not associated with the project allocated participants by their square-dancing groups equally into two arms (1:1), following a simple randomization process." subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 11a-i) Specify who was blinded, and who wasn't Specify who was blinded, and who wasn't. Usually, in web-based trials it is not possible to blind the participants [1, 3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering cointerventions (if any).
Does your paper address subitem 11a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described the blinding as "After the recruitment of all eligible participants, a statistician otherwise not associated with the project allocated participants by their square-dancing groups equally into two arms (1:1), following a simple randomization process. Although the participants were aware of the interventional nature of the study, they were blinded to their allocation status. Outcome assessors were blinded to the group assignments and were different from researchers who conducted and monitored the interventions." 11a-ii) Discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator" Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator".
11b) If relevant, description of the similarity of interventions (this item is usually not relevant for ehealth trials as it refers to similarity of a placebo or sham intervention to a active medication/intervention) 12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed Does your paper address subitem 11a-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described this as "Although the participants were aware of the interventional nature of the study, they were blinded to their allocation status." Does your paper address CONSORT subitem 11b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Not applicable.
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 12a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We addressed the clustering as "The intent-to-treat (ITT) analysis was adopted to examine the treatment effects, to minimize the selection bias and keep the original randomization design" and "The intention-to-treat (ITT) analysis was adopted to examine the treatment effects, to minimize the selection bias and keep the original randomization design" and " As participants clustered within dance groups, multilevel linear regression models were used to test for the intervention effect on continuous outcomes (i.e. acceptability) at individual participant level, while taking cluster level variation due to dancing groups into account. Similarly, multilevel negative binomial models were fitted to count outcomes (i.e. adoption), which followed an over-dispersed Poisson-like distribution. All models were adjusted for baseline covariates that were empirically suggested strong predictors for the adoption of wearable trackers. Length of individual follow-up days was further adjusted in the multilevel negative binomial model for daily step counts." 12a-i) Imputation techniques to deal with attrition / missing values Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials. Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4] Does your paper address subitem 12a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We described the imputation method as "Missing baseline covariates and missing outcomes were multiply imputed under the missing at random assumption, using individual demographic information, health status, other outcomes and cluster identifiers, separately by randomized arms to avoid biasing treatment effects towards the null. Altogether, 20 sets of complete datasets were imputed based on the chained equations. Primary analyses were then performed on each complete dataset and combined results were obtained according to the Rubin's combination rules." Does your paper address CONSORT subitem 12b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We only conducted sensitivity analysis with complete cases.

X26-i) Comment on ethics committee approval
subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential Does your paper address subitem X26-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We stated the IRB approval as "All participants read and signed the written informed consent approved by the Institutional Review Board (No. L2016-004) of the School of Public Health of Sun Yat-sen University."

x26-ii) Outline informed consent procedures
Outline informed consent procedures e.g., if consent was obtained offline or online (how? Checkbox, etc.?), and what information was provided (see 4a-ii). See [6] for some items to be included in informed consent documents.
Does your paper address subitem X26-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答 X26-iii) Safety and security procedures Safety and security procedures, incl. privacy considerations, and any steps taken to reduce the likelihood or detection of harm (e.g., education and training, availability of a hotline)

RESULTS
13a) For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome NPT: The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider in each center Does your paper address subitem X26-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答 13b) For each group, losses and exclusions after randomisation, together with reasons Does your paper address CONSORT subitem 13a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We specified the number of participants for each group as "Of the 88 dancing groups initially assessed for eligibility, 26 groups did not meet the cluster inclusion criteria mainly because of dancing style and group size. Nearly half of these groups (38/88, 43%) assessed declined to participate due to lack of trust or time. The rest 11 groups were also not eligible, as their group members were not local residents (n=2), hadn't been regularly practicing square dancing in the past 12 months (n=5), or less than two participants of the given group were willing to participate (n=4). The remaining 13 dancing groups were 1:1 randomized into the intervention arm (n=7) and the control arm (n=6). Among these eligible groups, 69 out of 82 participants (84 %) of the intervention arm and 80 out of 98 participants (82%) of the control arm received the allocated treatment. During the follow-up, no dancing groups withdrew; while five participants of the intervention arm and 19 of the control arm were lost to follow up, two participants of each arm had discontinued intervention due to technical problem, and one participant of the intervention arm and three participants of the control arm withdrew from the study. The final ITT analysis sample was based on the 149 participants of 13 dancing groups, out of whom 117 (78.5%) filled the users' feedback questionnaire of the wearable activity trackers." subitem not at all important 1 2 3 4 5 essential 14a) Dates defining the periods of recruitment and follow-up Does your paper address CONSORT subitem 13b? (NOTE: Preferably, this is shown in a CONSORT flow diagram) * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Loss and exclusion was presented in the flowchat (Figure 2), and we also stated in the Results as "During the follow-up, no dancing groups withdrew; while five participants of the intervention arm and 19 of the control arm were lost to follow up, two participants of each arm had discontinued intervention due to technical problem, and one participant of the intervention arm and three participants of the control arm withdrew from the study. The final ITT analysis sample was based on the 149 participants of 13 dancing groups, out of whom 117 (78.5%) filled the users' feedback questionnaire of the wearable activity trackers."

13b-i) Attrition diagram
Strongly recommended: An attrition diagram (e.g., proportion of participants still logging in or using the intervention/comparator in each group plotted over time, similar to a survival curve) or other figures or tables demonstrating usage/dose/engagement. Does your paper address subitem 13b-i?
Copy and paste relevant sections from the manuscript or cite the figure number if applicable (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答 subitem not at all important 1 2 3 4 5 essential 14b) Why the trial ended or was stopped (early) Does your paper address CONSORT subitem 14a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We addressed the period of recruitment and follow-up in the Method part as "This interim report covers the trial conducted between November 2017 and October 2018, consisting of seven-month recruitment and baseline assessment, three-month intervention, and the post-intervention reassessment." 14a-i) Indicate if critical "secular events" fell into the study period Indicate if critical "secular events" fell into the study period, e.g., significant changes in Internet resources available or "changes in computer hardware or Internet delivery resources" Does your paper address subitem 14a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 您的回答 Does your paper address CONSORT subitem 14b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study 15) A

15-i) Report demographics associated with digital divide issues
In ehealth trials it is particularly important to report demographics associated with digital divide issues, such as age, education, gender, social-economic status, computer/Internet/ehealth literacy of the participants, if known.
Does your paper address subitem 15-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We reported "Sociodemographic characteristics and health status were similar between the two arms. Most of the participants were married older women (mean age 62 years), retired, with an educational degree of senior high school, had diagnosed chronic diseases but were physically and mentally sound. The intervention arm had fewer female participants and lower mean TICS scores than the control arm. The average group size was 9.9 and 13.3 participants for the intervention arm and the control arm respectively." 16) For each group, number of participants (denominator) included in each analysis and whether the analysis was by original assigned groups subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 16-i) Report multiple "denominators" and provide definitions Report multiple "denominators" and provide definitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at specific pre-defined time points of interest (in absolute and relative numbers per group). Always clearly define "use" of the intervention.
Does your paper address subitem 16-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We clearly indicated the number of participant in the result and in the flowchart ( Figure 2). As we stated, "The final ITT analysis sample was based on the 149 participants of 13 dancing groups, out of whom 117 (78.5%) filled the users' feedback questionnaire of the wearable activity trackers."

16-ii) Primary analysis should be intent-to-treat
Primary analysis should be intent-to-treat, secondary analyses could include comparing only "users", with the appropriate caveats that this is no longer a randomized sample (see 18-i).
17a) For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval) subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 16-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We applied ITT for the primary outcome analysis, which was mentioned in the statistical analysis section and results section.
Does your paper address CONSORT subitem 17a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study For each primary outcome we provided estimated effects with its 95% confidence interval, for instance, "After adjusting for clustering effect, baseline unbalanced covariates and predictors for adoption, the absolute group difference in the overall acceptability score was estimated to be 6.8 points (95% CI 2.2 to 11.4) higher in the intervention arm than the control arm." 17a-i) Presentation of process outcomes such as metrics of use and intensity of use In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational definitions is critical. This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length". These must be accompanied by a technical description how a metric like a "session" is defined (e.g., timeout after idle time) [1] (report under item 6a).
17b) For binary outcomes, presentation of both absolute and relative effect sizes is recommended 18) Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-specified from exploratory Does your paper address subitem 17a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study As our study was aimed to explore the acceptability and adoption of wearable activity trackers by mid-and older-aged adults, we specifically reported measures regarding these two process outcomes, for instance, "Regarding adoption outcomes measured by step count data, the medium of the percentage of days that participants had valid step count record were 44.1% vs 11.4% for the intervention and control arms, with 10% and 25% of each arm having invalid step counts records." Does your paper address CONSORT subitem 17b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We reported both absolute and relative effect size for each outcome measures by intervention arms with (

18-i) Subgroup analysis of comparing only users
A subgroup analysis of comparing only users is not uncommon in ehealth trials, but if done, it must be stressed that this is a self-selected sample and no longer an unbiased sample from a randomized trial (see 16-iii).
Does your paper address subitem 18-i? Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We reported the qualitative feedback from our participants in the Qualitative feedback from participants and researchers section, as "Qualitative feedbacks from participants and researchers' observations indicated some common problems encountered by both arms. In terms of enjoyment and comfort of wearing, participants noted that activity trackers were extremely uncomfortable to wear when the weather was hot and humid, let alone during dancing if they sweat heavily. Some participants reflected that the figures displayed on the trackers were too small to read, such that they had to wear glasses to read them. Regarding usefulness, a few participants thought that the function of the wearable activity trackers was quite limited; while other functions, such as blood pressure monitoring, were more useful and relevant from their point of view. For instance, some participants commented that they preferred the sleep monitoring function to the PA monitoring function. As for ease-of-use, our researchers found that they received most common inquiries about how to charge the trackers and how to synchronize data with the paired smart phone." subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential 22-i) Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use) Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use).
Does your paper address subitem 22-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We summarized our main findings in line with the study questions in the first paragraph of the Discussion, as "We assessed the effectiveness of a social group-based deployment intervention informed by the IMBS framework to promote wearable activity trackers' acceptability and adoption among community-dwelling mid-and older-aged adults. In line with our hypotheses, the results revealed that our intervention significantly increased participants' acceptability, mainly driven by improvements in the perceived motivation, usefulness and ease-of-use. The intervention also effectively promoted participants' adoption, quantified as twice the amount of valid step count data of the intervention arm than the control arm." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study We concluded our study by highlighting its limitations alongside directions for future studies, such as "Second, as our intervention package addressed the three main barriers of behavior changes jointly according to the IMBS framework, we were not able to distinguish the unique contribution of each intervention component to the program effect. Additional research design may be considered in future studies, such as the factorial experiment that may allow the evaluation of sole and joint effects of such an intervention. "and "Lastly, as a phase 1 study, we have yet to capture and report long-term acceptability, adoption and health-related outcomes, which are needed to establish the intervention's long-term behavior maintenance and effectiveness."

20-i) Typical limitations in ehealth trials
Typical limitations in ehealth trials: Participants in ehealth trials are rarely blinded. Ehealth trials often look at a multiplicity of outcomes, increasing risk for a Type I error. Discuss biases due to non-use of the intervention/usability issues, biases through informed consent procedures, unexpected events. 21) Generalisability (external validity, applicability) of the trial findings NPT: External validity of the trial findings according to the intervention, comparators, patients, and care providers or centers involved in the trial Does your paper address subitem 20-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Limitations of the current analysis were outlined as "Several limitations of our study are worth noting. First, significantly underestimating the challenges in the recruitment, we recruited only 13 dancing groups rather than the 24 groups as expected. The participants recruited thus were likely to be more prone to technology than the general mid-and olderadults. However, this self-selection of the participants should not affect the internal validity of our program effects as the intervention and control arms shared similar characteristics and were randomly assigned. The self-selection, however, limited our program implication to the broader mid-and older-aged population. Second, as our intervention package addressed the three main barriers of behavior changes jointly according to the IMBS framework, we were not able to distinguish the unique contribution of each intervention component to the program effect. Additional research design may be considered in future studies, such as the factorial experiment that may allow the evaluation of sole and joint effects of such an intervention. Third, our intervention relied on social interactions and required regular assistance from the research staff, particularly in the initial phase. Although social support and comparison functions have been integrated into many activity trackers nowadays, our assistance level is likely to be higher than what commercially available activity trackers typically provide. Lastly, as an interim study, we have yet to capture and report long-term acceptability, adoption and health-related outcomes, which are needed to establish the intervention's long-term behavior maintenance and effectiveness."