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Ecological Momentary Assessment of Physical Activity: Validation Study.
Gregory Knell1, Kelley Pettee Gabriel2, Michael S Businelle3
1Michael and Susan Dell Center for Healthy Living, Department of Health Promotion and Behavioral Sciences, University of Texas Health Science Center (UTHealth) at Houston, Houston, TX, United States.
Journal of Medical Internet Research
|July 20, 2017
Summary
Mobile ecological momentary assessment (EMA) offers a more accurate way to measure physical activity (PA) than traditional methods. This study found EMA had better agreement with accelerometers, suggesting it’s a practical alternative for assessing PA.
Area of Science:
- Exercise Physiology
- Biomedical Informatics
- Public Health
Background:
- Ecological momentary assessment (EMA) offers a promising approach to measuring physical activity (PA) with reduced bias compared to traditional self-report methods.
- EMA provides valuable contextual data alongside PA estimates.
Purpose of the Study:
- To evaluate the convergent validity of PA estimates obtained through EMA against accelerometry.
- To compare the accuracy of EMA-derived PA data with traditional self-report questionnaires (IPAQ, BRFSS).
Main Methods:
- Participants (N=238) completed daily mobile EMA for 7 days, alongside self-reports using IPAQ and BRFSS.
- Objective PA data was collected using accelerometry over the same 7-day period.
- Statistical analyses included Spearman and Lin's concordance correlation coefficients to assess linear association and agreement.
Main Results:
- EMA-assessed PA demonstrated statistically significant linear associations with accelerometer data for sedentary time, moderate-intensity PA, and MVPA.
- EMA estimates showed significantly better agreement with accelerometer data compared to traditional self-report methods (IPAQ, BRFSS).
- Significant correlations were observed for moderate-intensity PA (EMA: ρ=.29) and MVPA (EMA: ρ=.31).
Conclusions:
- Mobile EMA provides a more valid and reliable method for assessing physical activity in free-living conditions compared to traditional questionnaires.
- EMA represents a practical and effective alternative to accelerometers for objective PA assessment.
