The change of gait parameters during walking at different percentage of preferred walking speed for healthy adults aged 20-60 years.

This study aims to investigate the effects of age, gender and walking speed on the gait performance during walking at a range of percentage of preferred walking speed (PPWS). The subjects were aged from 20 to 60 years and both genders were equally represented. A nested-factorial analysis of variance was employed. The independent variables include walking speed (80%, 100%, 120%, and 140% PPWS), age (young, middle, and older groups) and gender. The response measures include lower limb joint motion, vertical ground reaction force (VGRF), muscle electromyography (EMG), heart rate, and perceived exertion of whole body and local areas. The results show that different age and gender groups had similar gait performance on most of the joint motions, HR, as well as the perceived exertions while walking at a range of PPWS. In addition, these performance generally increased with the increasing walking speed and the trend becomes more obvious when the speed was higher than 120% PWS. Age and gender differences have been found in VGRFs and muscle EMG. Females exhibited significantly higher VGRF in the heel-strike and toe-off stages, as well as higher tibialis anterior muscle activity. Older subjects had significantly higher rectus femoris muscle activity than younger adults. Besides, the interaction between gender and walking speed was significant on VGRF in the toe-off stage. Further discussions are addressed.