Effects of a 30-minute walk on ground reaction forces during walking with an external load
To investigate effects of a 30-minute walk on kinetics of walking with an external load, ten subjects performed five walking trials across a force platform for five conditions. Walking speed was 1.57m/s for all conditions. The first two conditions had subjects walk without (C1) and with (C2) backpack load. Subjects then walked on a treadmill at 1.57m/s for 30 minutes. At 10 minute intervals GRF data were collected. In comparing C1 and C2, dependent variables F1, F2, and Favg revealed increases of 10.45%, 13.68%, and 11.75% respectively (p < 0.01) indicating a mechanical response. No effect for time was observed for any variable tested. Therefore, the null hypothesis that load does not have an effect on vertical GRF was rejected. The null hypothesis that time does not have an effect on vertical GRF was not rejected. Overall, forces were elevated during load carrying, which may result in added stress on anatomical structures.
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