%0 Journal Article
%@ 1438-8871
%I JMIR Publications
%V 19
%N 5
%P e186
%T Design and Evaluation of a Computer-Based 24-Hour Physical Activity Recall (cpar24) Instrument
%A Kohler,Simone
%A Behrens,Gundula
%A Olden,Matthias
%A Baumeister,Sebastian E
%A Horsch,Alexander
%A Fischer,Beate
%A Leitzmann,Michael F
%+ Department of Epidemiology and Preventive Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, Regensburg, 93053, Germany, 49 941 944 ext 5217, Gundula.Behrens@klinik.uni-regensburg.de
%K web-based method
%K validity
%K reliability
%K usability
%K lifestyle behavior
%K physical activity
%K sedentary behavior
%D 2017
%7 30.05.2017
%9 Original Paper
%J J Med Internet Res
%G English
%X Background: Widespread access to the Internet and an increasing number of Internet users offers the opportunity of using Web-based recalls to collect detailed physical activity data in epidemiologic studies. Objective: The aim of this investigation was to evaluate the validity and reliability of a computer-based 24-hour physical activity recall (cpar24) instrument with respect to the recalled 24-h period. Methods: A random sample of 67 German residents aged 22 to 70 years was instructed to wear an ActiGraph GT3X+ accelerometer for 3 days. Accelerometer counts per min were used to classify activities as sedentary (<100 counts per min), light (100-1951 counts per min), and moderate to vigorous (≥1952 counts per min). On day 3, participants were also requested to specify the type, intensity, timing, and context of all activities performed during day 2 using the cpar24. Using metabolic equivalent of task (MET), the cpar24 activities were classified as sedentary (<1.5 MET), light (1.5-2.9 MET), and moderate to vigorous (≥3.0 MET). The cpar24 was administered twice at a 3-h interval. The Spearman correlation coefficient (r) was used as primary measure of concurrent validity and test-retest reliability. Results: As compared with accelerometry, the cpar24 underestimated light activity by −123 min (median difference, P difference <.001) and overestimated moderate to vigorous activity by 89 min (P difference <.001). By comparison, time spent sedentary assessed by the 2 methods was similar (median difference=+7 min, P difference=.39). There was modest agreement between the cpar24 and accelerometry regarding sedentary (r=.54), light (r=.46), and moderate to vigorous (r=.50) activities. Reliability analyses revealed modest to high intraclass correlation coefficients for sedentary (r=.75), light (r=.65), and moderate to vigorous (r=.92) activities and no statistically significant differences between replicate cpar24 measurements (median difference for sedentary activities=+10 min, for light activities=−5 min, for moderate to vigorous activities=0 min, all P difference ≥.60). Conclusion: These data show that the cpar24 is a valid and reproducible Web-based measure of physical activity in adults. 
%M 28559229
%R 10.2196/jmir.7620
%U http://www.jmir.org/2017/5/e186/
%U https://doi.org/10.2196/jmir.7620
%U http://www.ncbi.nlm.nih.gov/pubmed/28559229