Reliability of ankle isometric, isotonic, and isokinetic strength and power testing in older women. Phys Ther

Background. Ankle strength (force-generating capacity) and power (work pro-duced per unit of time or product of strength and speed) capabilities influence physical function (eg, walking, balance) in older adults. Although strength and power parameters frequently are measured with dynamometers, few studies have examined the reliability of measurements of different types of contractions. Objective. The purpose of this study was to examine relative and absolute intrarater reliability of isometric, isotonic, and isokinetic ankle measures in older women. Design. This was a prospective, descriptive methodological study. Methods. The following dorsiflexion (DF) and plantar-flexion (PF) measures were assessed twice (7 days apart) by the same examiner in 30 older women (mean age73.3 years, SD4.7): isometric peak torque and rate of torque development (RTD), isotonic peak velocity, average acceleration and peak power, and isokinetic peak torque and peak power (30°/s and 90°/s). Several statistical methods were used to examine relative and absolute reliability