Comparing GPS, Log, Survey, and Accelerometry to Measure Physical Activity
Published Date:Jan 2016
Source:Am J Health Behav. 40(1):123-131.
Pubmed Central ID:PMC4866646
Funding:T32 HL 098048/HL/NHLBI NIH HHS/United States
T32 HL098048/HL/NHLBI NIH HHS/United States
U48 DP 000043/DP/NCCDPHP CDC HHS/United States
U48 DP000043/DP/NCCDPHP CDC HHS/United States
Both self-report and objective measures have strengths and limitations for studying physical activity (PA) and travel. We explored how objectively measured global positioning system (GPS) and accelerometer data matches with travel logs and questionnaires in predicting trip duration and PA.
In a study of PA and travel among residents in Atlanta, GA conducted in 2008–2009, 99 participants wore GPS devices and accelerometers, and recorded all trips in a log for 5 consecutive days. Participants also completed a self-administered questionnaire on PA and travel behaviors.
There was good agreement between GPS and log for assessment of trip duration, although log measures overestimated trip duration (concordance correlation coefficient 0.53 [0.47, 0.59]; Bland-Altman estimate 0.76 [0.16, 3.71] comparing GPS to log). Log measures underestimated light PA and overestimated moderate PA compared to accelerometry when greater than zero moderate PA was reported.
It is often not feasible to deploy accelerometry or GPS devices in population research because these devices are expensive and require technical expertise and data processing. Questionnaires and logs provide inexpensive tools to assess PA and travel with reasonable concordance with objective measures. However, they have shortcomings in evaluating the presence and amount of light and moderate PA. Future questionnaires and logs should be developed to evaluate sensitivity to light and moderate PA.
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