2000 Volume 4 Issue 1 Pages 31-38
The purpose of this study is to clarify the effects of differences in center-of-gravity (CG) of a backpack on joint moment-of-force during walking. On three different occasions, six male subjects walked on a straight platform at a voluntary speed. During walking, they randomly shouldered a backpack which had a different position of CG, that was about 88% height (HP) or 72% height (MP) or 55% height (LP), respectively. The motion and ground-reaction-force were measured by high speed video and force platform analysis. The following results were obtained:
1) The moment-of-force produced by the weight of HAT (head & arm & trunk) with a backpack acted on the forward rotation of the upper body during walking. And that in the higher position was significantly larger than that in the lower.
2) The hip extension and abduction moment-of-force in the higher was significantly larger than that in the lower.
3) The maximal angle of forward tilting during walking in the lower was significantly larger than that in the higher.
4) The walking speed in the higher was significantly larger than that in the lower.
Therefore, we consider that the higher CG of backpack may increase biomechanical efficiency during walking. However the higher CG backpack may act large stress on hip extensor and abductor muscles.
