A portable, easily performed muscle power test and its association with falls by elderly persons

This study developed and evaluated a simple, inexpensive, and safe screening test for assessment of falling risk in elderly persons. Subjects sat in chairs (hips and knees at 90°) with their feet over a force transducer and stood as forcefully as possible. After standing for five seconds, they sat as fast as possible. The rate of change in force ( dF dT) for standing and sitting were calculated from data collected by computer. A group of nonfallers (n = 23, age = 23 to 72 years) and a group of fallers (n = 22, age = 63 to 92 years) were studied. Nonfallers' dF dT for standing decreased linearly from 4kg·sec^-1·kg^-1 to 2.5kg·sec^-1·kg^-1. Values in fallers decreased linearly from 3kg·sec^-1·kg^-1 to 0.1kg·sec^-1·kg^-1. The dF dT for sitting was not dependent on age in either group. Fallers had lower dF dT than nonfallers (1.3 ± .6kg·sec^-1·kg^-1 and 2.3 ± .01kg·sec^-1·kg^-1, respectively). Seventeen of 22 fallers were identified by a reduced dF dT and reduced overshoot force (kg).