%0 Journal Article
%@ 1438-8871
%I JMIR Publications
%V 19
%N 7
%P e253
%T Ecological Momentary Assessment of Physical Activity: Validation Study
%A Knell,Gregory
%A Gabriel,Kelley Pettee
%A Businelle,Michael S
%A Shuval,Kerem
%A Wetter,David W
%A Kendzor,Darla E
%+ Michael and Susan Dell Center for Healthy Living, Department of Health Promotion and Behavioral Sciences, University of Texas Health Science Center (UTHealth) at Houston, 7000 Fannin, #2528, Houston, TX, 77030, United States, 1 713 500 9678, gregory.knell@uth.tmc.edu
%K accelerometry
%K behavioral risk factor surveillance system
%K ecological momentary assessment
%K self-report
%K data accuracy
%D 2017
%7 18.07.2017
%9 Original Paper
%J J Med Internet Res
%G English
%X Background: Ecological momentary assessment (EMA) may elicit physical activity (PA) estimates that are less prone to bias than traditional self-report measures while providing context. Objectives: The objective of this study was to examine the convergent validity of EMA-assessed PA compared with accelerometry. Methods: The participants self-reported their PA using International Physical Activity Questionnaire (IPAQ) and Behavioral Risk Factor Surveillance System (BRFSS) and wore an accelerometer while completing daily EMAs (delivered through the mobile phone) for 7 days. Weekly summary estimates included sedentary time and moderate-, vigorous-, and moderate-to vigorous-intensity physical activity (MVPA). Spearman coefficients and Lin’s concordance correlation coefficients (LCC) examined the linear association and agreement for EMA and the questionnaires as compared with accelerometry. Results: Participants were aged 43.3 (SD 13.1) years, 51.7% (123/238) were African American, 74.8% (178/238) were overweight or obese, and 63.0% (150/238) were low income. The linear associations of EMA and traditional self-reports with accelerometer estimates were statistically significant (P<.05) for sedentary time (EMA: ρ=.16), moderate-intensity PA (EMA: ρ=.29; BRFSS: ρ=.17; IPAQ: ρ=.24), and MVPA (EMA: ρ=.31; BRFSS: ρ=.17; IPAQ: ρ=.20). Only EMA estimates of PA were statistically significant compared with accelerometer for agreement. Conclusions: The mobile EMA showed better correlation and agreement to accelerometer estimates than traditional self-report methods. These findings suggest that mobile EMA may be a practical alternative to accelerometers to assess PA in free-living settings. 
%M 28720556
%R 10.2196/jmir.7602
%U http://www.jmir.org/2017/7/e253/
%U https://doi.org/10.2196/jmir.7602
%U http://www.ncbi.nlm.nih.gov/pubmed/28720556