Test-Retest reliability of activPAL in measuring sedentary behavior and physical activity in people with type 2 diabetes

Background: To investigate how changes in sedentary behavior relate to health outcomes, it is important to establish the test-retest reliability of activity monitors in measuring habitual sedentary behavior in people with type 2 diabetes (T2D) as a prerequisite for interpreting this information. Thus, the authors' objective was to examine the test-retest reliability of a common activity monitor (activPAL^™) in measuring sedentary behavior and physical activity in people with T2D. Methods: Sedentary-time, standing-time, stepping-time, step-count, and sit-to-stand transitions were obtained from two 7-day assessment periods separated by at least 1 week. Test-retest reliability was determined with the intraclass correlation coefficient (ICC) to compare sedentary and activity measures between the 2 time points. Results: A total of 30 participants with self-reported T2D completed the study (age 65 [6] y, 63% women, body mass index 33.3 [5] kg/m²). High test-retest reliability was found for sedentary-time (ICC =.79; 95% confidence interval [CI],.61-.89) and standing-time (ICC =.74; 95% CI,.53-.87). Very high test-retest reliability was found for stepping-time (ICC =.90; 95% CI,.81-.95), step-count (ICC =.91; 95% CI,.83-.96), and sit-to-stand transitions (ICC =.90; 95% CI,.79-.95). Conclusion: The activPAL^™ device showed high to very high test-retest reliability in measuring all tested activity categories in people with T2D.