What is most appropriate number of repetitions of the sit-to-stand test in older adults: a reliability study

The most frequently employed versions of the sit-to-stand test (STST) are the 5 times STSΤ and the 30 seconds STST. However, it is not known whether a variation with different number of repetitions or time could be more appropriate for older adults. The objective of this study was to investigate the reliability of STST at different time points and number of repetitions. The test was performed in 33 older adults (73±6.1 years) for 40 seconds. The participants performed the procedure twice with a day interval between the sessions. The test was video-taped and the data were processed by two examiners. The highest test-retest reliability was found for the 4^th (ICC=0.73, SEM=1.48, SDD=1.68), 5^th (ICC=0.76, SEM=1.73, SDD=1.97) and 6^th repetition (ICC=0.78, SEM=1.78, SDD=2.03). The inter-rater reliability was excellent independently of the number of trials (ICC>0.9). The correlation of the time at the 4^th and 6^th repetition with the time at the traditionally selected 5^th repetition was excellent (r>0.9). The termination of the STST at the 4^th repetition seems to provide equally reliable and valid estimations with the termination at the 5^th repetition. Future studies should examine a 4 times STST since the reduction of the number of repetitions may be less tiring and safer for older adults.