Test–retest reliability of sensor-based sit-to-stand measures in young and older adults

Abstract

This study investigated test–retest reliability of sensor-based sit-to-stand (STS) peak power and other STS measures in young and older adults. In addition, test–retest reliability of the sensor method was compared to test–retest reliability of the Timed Up and Go Test (TUGT) and Five-Times-Sit-to-Stand Test (FTSST) in older adults. Ten healthy young female adults (20–23 years) and 31 older adults (21 females; 73–94 years) participated in two assessment sessions separated by 3–8 days. Vertical peak power was assessed during three (young adults) and five (older adults) normal and fast STS trials with a hybrid motion sensor worn on the hip. Older adults also performed the FTSST and TUGT. The average sensor-based STS peak power of the normal STS trials and the average sensor-based STS peak power of the fast STS trials showed excellent test–retest reliability in young adults (intra-class correlation (ICC)≥0.90; zero in 95% confidence interval of mean difference between test and retest (95%CI of D); standard error of measurement (SEM)≤6.7% of mean peak power) and older adults (ICC≥0.91; zero in 95%CI of D; SEM≤9.9%). Test–retest reliability of sensor-based STS peak power and TUGT (ICC=0.98; zero in 95%CI of D; SEM=8.5%) was comparable in older adults, test–retest reliability of the FTSST was lower (ICC=0.73; zero outside 95%CI of D; SEM=14.4%). Sensor-based STS peak power demonstrated excellent test–retest reliability and may therefore be useful for clinical assessment of functional status and fall risk.