Determining criteria to predict repeatability of performance in older adults: using coefficients of variation for strength and functional measures

Reliable measures of muscle strength and functional capacity in older adults are essential. The aim of this study was to determine whether coefficients of variation (CVs) of individuals obtained at the first session can infer repeatability of performance in a subsequent session. Forty-eight healthy older adults (mean age 68.6 ± 6.1 years; age range 60 - 80 years) completed two assessment sessions, and on each occasion undertook: Dynamometry for isometric and isokinetic quadriceps strength, 6 metre fast walk (6mFWT), timed up and go (TUG), stair climb and descent, and vertical jump. Significant linear relationships were observed between CVs in session 1 and the percentage difference between sessions 1 and 2 for torque at 60, 120, 240 and 360º/s, 6mFWT, TUG, stair climb and stair descent. The results of this study could be used to establish criteria for determining an acceptably reliable performance in strength and functional tests