Validity and reliability of inertial measurement units on gait, static balance and functional mobility performance among community-dwelling older adults: a systematic review and meta-analysis.

Purpose: This systematic review and meta-analysis investigated validity and test-retest reliability of inertial measurement units (IMUs) in gait metrics, static balance and functional mobility performance in community-dwelling older adults. Methods: Spatiotemporal/biomechanical outcomes were meta-analyzed using intraclass correlation coefficients (ICCs) or Pearson correlation coefficients (r) for validity and reliability, respectively. Results: In our systematic review of 56 articles and meta-analysis of 38 articles, the included studies varied in quality from low-to-moderate. During validity analysis, IMU-derived metrics, including walking speed, cadence, step/stride time, step time variability, step/stride length and duration of sit-to-stand (STS) test/timed up, and go test (TUGT) exhibited excellent (ICCs) or good-to-excellent (r values) agreement with gold standards. In terms of reliability, excellent test-retest consistency was found for walking speed, cadence, step/stride time, stance/swing time, step/stride length during gait, individual STS duration, TUGT duration and walking speed during the 6-min walk test. Conclusions: Due to consistently high levels of validity and reliability, the present study supported the use of IMUs for measuring gait spatiotemporal outcomes. However, caution was advised when applying spatiotemporal variability and symmetry metrics. In addition, characterized by moderate-to-good validity and reliability, current review provides evidence of a neutral nature regarding the utilization of IMUs for static balance and functional mobility performance.