BACKGROUND: The purpose of this study was to determine 1) the test-retest reliability of adult accelerometer-measured physical activity, and 2) how data processing decisions affect physical activity levels and test-retest reliability. METHODS: 143 people wore the ActiGraph accelerometer for 2 7-day periods, 1 to 4 weeks apart. Five algorithms, varying nonwear criteria (20 vs. 60 min of 0 counts) and minimum wear requirements (6 vs. 10 hrs/day for ≥ 4 days) and a separate algorithm requiring ≥ 3 counts per min and ≥ 2 hours per day, were used to process the accelerometer data. RESULTS: Processing the accelerometer data with different algorithms resulted in different levels of counts per day, sedentary, and moderate-to-vigorous physical activity. Reliability correlations were very good to excellent (ICC = 0.70-0.90) for almost all algorithms and there were no significant differences between physical activity measures at Time 1 and Time 2. CONCLUSIONS: This paper presents the first assessment of test-retest reliability of the Actigraph over separate administrations in free-living subjects. The ActiGraph was highly reliable in measuring activity over a 7-day period in natural settings but data were sensitive to the algorithms used to process them.
BACKGROUND: The purpose of this study was to determine 1) the test-retest reliability of adult accelerometer-measured physical activity, and 2) how data processing decisions affect physical activity levels and test-retest reliability. METHODS: 143 people wore the ActiGraph accelerometer for 2 7-day periods, 1 to 4 weeks apart. Five algorithms, varying nonwear criteria (20 vs. 60 min of 0 counts) and minimum wear requirements (6 vs. 10 hrs/day for ≥ 4 days) and a separate algorithm requiring ≥ 3 counts per min and ≥ 2 hours per day, were used to process the accelerometer data. RESULTS: Processing the accelerometer data with different algorithms resulted in different levels of counts per day, sedentary, and moderate-to-vigorous physical activity. Reliability correlations were very good to excellent (ICC = 0.70-0.90) for almost all algorithms and there were no significant differences between physical activity measures at Time 1 and Time 2. CONCLUSIONS: This paper presents the first assessment of test-retest reliability of the Actigraph over separate administrations in free-living subjects. The ActiGraph was highly reliable in measuring activity over a 7-day period in natural settings but data were sensitive to the algorithms used to process them.
Authors: Lea Ann Matura; Haochang Shou; Jason S Fritz; K Akaya Smith; Anjali Vaidya; Diane Pinder; Christine Archer-Chicko; Danielle Dubow; Harold I Palevsky; Marilyn S Sommers; Steven M Kawut Journal: Chest Date: 2016-02-15 Impact factor: 9.410
Authors: Kelly R Evenson; Daniela Sotres-Alvarez; Y U Deng; Simon J Marshall; Carmen R Isasi; Dale W Esliger; Sonia Davis Journal: Med Sci Sports Exerc Date: 2015-04 Impact factor: 5.411
Authors: Tiago V Barreira; Marc T Hamilton; Lynette L Craft; Susan M Gapstur; Juned Siddique; Theodore W Zderic Journal: J Sci Med Sport Date: 2015-05-22 Impact factor: 4.319
Authors: Reynolette Ettienne; Claudio R Nigg; Fenfang Li; Yuhua Su; Katalina McGlone; Bret Luick; Alvin Tachibana; Christina Carran; Jobel Mercado; Rachel Novotny Journal: Hawaii J Med Public Health Date: 2016-04