Author:

Keywords:

Science & Technology, Physical Sciences, Technology, Chemistry, Analytical, Engineering, Electrical & Electronic, Instruments & Instrumentation, Chemistry, Engineering, test-retest, mobility limitation, chair rise, LOWER-EXTREMITY FUNCTION, TEST-RETEST RELIABILITY, BODY FIXED SENSOR, PHYSICAL-ACTIVITY, DISABILITY, KINEMATICS, MORTALITY, ACCURACY, YOUNG, AGE, test–retest, Accelerometry, Aged, Female, Humans, Independent Living, Reproducibility of Results, Thigh, 12Z5720N#55263160, 0301 Analytical Chemistry, 0805 Distributed Computing, 0906 Electrical and Electronic Engineering, Analytical Chemistry, 4008 Electrical engineering, 4009 Electronics, sensors and digital hardware, 4606 Distributed computing and systems software

Abstract:

(1) Background: The purpose of this study was to evaluate the day-to-day variability and year-to-year reproducibility of an accelerometer-based algorithm for sit-to-stand (STS) transitions in a free-living environment among community-dwelling older adults. (2) Methods: Free-living thigh-worn accelerometry was recorded for three to seven days in 86 (women n = 55) community-dwelling older adults, on two occasions separated by one year, to evaluate the long-term consistency of free-living behavior. (3) Results: Year-to-year intraclass correlation coefficients (ICC) for the number of STS transitions were 0.79 (95% confidence interval, 0.70-0.86, p < 0.001), for mean angular velocity-0.81 (95% ci, 0.72-0.87, p < 0.001), and maximal angular velocity-0.73 (95% ci, 0.61-0.82, p < 0.001), respectively. Day-to-day ICCs were 0.63-0.72 for number of STS transitions (95% ci, 0.49-0.81, p < 0.001) and for mean angular velocity-0.75-0.80 (95% ci, 0.64-0.87, p < 0.001). Minimum detectable change (MDC) was 20.1 transitions/day for volume, 9.7°/s for mean intensity, and 31.7°/s for maximal intensity. (4) Conclusions: The volume and intensity of STS transitions monitored by a thigh-worn accelerometer and a sit-to-stand transitions algorithm are reproducible from day to day and year to year. The accelerometer can be used to reliably study STS transitions in free-living environments, which could add value to identifying individuals at increased risk for functional disability.