Skeletal accelerations measured during different exercises.

Abstract

Exercise is often suggested as a means of reducing the effects of osteoporosis in post-menopausal women. In response to an increase in physical activity, bone mass can be increased and several studies have investigated the effectiveness of different exercises in increasing bone mass. In this study we have attempted to quantify the effect of different exercises by measuring the accelerations produced during various exercises. Accelerations have been measured at the ankle of normal subjects during a series of impulsive (walking, running and walking up and down stairs) and non-impulsive (cycling) exercises. Accelerations were measured using an accelerometer attached to a stiff cuff which straps around the ankle. Signals from the accelerometer are amplified and recorded using a specially developed portable data-logging system. THe principal parameters measured were the maximum change of acceleration (peak to peak) and the rate of change of acceleration. From the results it was observed that running and walking up and down stairs produced the highest peak-to-peak change (running = 8.08 g; walking downstairs = 8.11 g) and rate of change of acceleration (running = 2.14 g/s; walking downstairs = 2.07 g/s). By contrast, a non-impulsive exercise such as cycling produced relatively low values of peak-to-peak change (2.24 g) and rate of change (0.23 g/s) of acceleration.