Day-to-Day Variability and Year-to-Year Reproducibility of Accelerometer-Measured Free-Living Sit-to-Stand Transitions Volume and Intensity among Community-Dwelling Older Adults

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.

Association of Sit-to-Stand Capacity and Free-Living Performance Using Thigh-Worn Accelerometers among 60- to 90-Yr-Old Adults

“…Future studies could examine whether STS performance differs between working days and days off. Second, although we have found the accuracy of identifying STS transitions to be greater than 90% and the angular velocity determination to be accurate (14,15), there are always misclassifications of free-living movements. There is no way to know for sure whether a behavior that appears to be an STS transition in the free-living accelerometer data is actually an STS transition and whether an exceptional technique (e.g., arm utilization, seat height, assistance from another person) was used to perform a given STS transition.…”

“…The combination of the relatively high capacity demand, and the fact that people engage with the STS multiple times a day makes this movement a potential candidate for free-living strength-demanding activity monitoring. Wearable sensor technology has made it possible to measure and detect STS transitions based on thigh angular velocity in free-living environment (14)(15)(16)(17)(18). The test capacity of STS transitions in the laboratory and clinical settings has commonly been studied using the 5ÂSTS test completion time (19,20).…”

Sedentary Patterns and Sit-to-Stand Transitions in Open Learning Spaces and Conventional Classrooms among Primary School Students

“…The MAD method used for assessing accelerometer data in this study has documented validity and reliability across different accelerometer brands [34,35]. The sit-to-stand transition algorithm has been shown to be reliable in free-living environments in community-dwelling older adults [40], but it has not been yet validated for children.…”

“…Sedentary bouts of less than one minute were excluded, and a sedentary bout was considered to end with any interruption in sedentary time [39]. Sitto-stand transitions were assessed using a thigh-worn accelerometer, attached on the thigh, with the sit-to-stand transition algorithm [40] using MATLAB (R2019a, The MathWorks Inc., Natick, MA, USA). To account for any differences in wear time of the accelerometers during classroom time, outcome variables were calculated in proportion to 60 min of classroom time [18].…”

Association Between Free-Living Sit-to-Stand Transition Characteristics, and Lower-Extremity Performance, Fear of Falling, and Stair Negotiation Difficulties Among Community-Dwelling 75 to 85-Year-Old Adults

“…The angular velocity quantification accuracy of STS transitions at different velocities was good when the angular velocity detected by the algorithm was compared against 2D motion analysis ( Supplementary Video ). In addition, the volume and intensity of STS transitions monitored by thigh-worn accelerometer are reproducible from day-to-day to year-to-year ( 29 ).…”