Influence of Arm Motion on Spatio-temporal Gait Parameters and on Force Data

Computational models of walking are not often coherent with experimental design. Although the upper extremities have an active role in human gait, their swing is often neglected or restricted in contrast with the experiments where the subjects are asked to walk freely. The purpose of this study is to assess differences on gait parameters and force data, comparing five arm swing patterns during walking. Motion analysis was performed on six healthy males, using a 10 cameras capture system and two AMTI force plates. Stride time and length, step time and length as well as ground reaction forces and free vertical moment were compared among groups. Results included no statistically difference (p> 0.05) for the gait parameters and the ground reaction forces. However, the main influence of the arm swing was found on the free vertical moment induced by lower limb swing to counterbalance trunk torque. In fact, restraining arms from swinging caused an increase of peak magnitude in the vertical toque between foot and ground. This suggested that although the arms have a little effect on the sagittal and frontal plane, their contribution is relevant in the transversal one. Therefore, an agreement between experiment-modelling is required, especially when upper body inverse dynamic problems are investigated.