The Influence Of Arms Swing To The Coordination Of Trunk Movement During Walking

Objective:To investigate the adaptation of the body to maintain the gait coordination, and explore the function of arms swing in the coordination of movement of the trunk. Method:13 subjects were recruited. The markers were attached to the segments of the body. They walked in treadmill in 6 velocities, while they swinged arms naturally, crossed tow arms in front of them and put single arm in front of them. All 18 conditions were randomized. The kinematic parameters of these segments were calculated and compared difference between them. Results:Thorax-spine transverse rotation amplitude (TRA), lumbar-spine TRA, pelvic TRA, spine TRA and leg TRA were significantly increased with speed increased. Thorax-spine TRA, lumbar-spine TRA, spine TRA and leg TRA were decreased when arms were constrained. The thorax-lumbar and thorax-pelvis relative Fourier phase (RFP) were significantly decrease when arms were constrained. But arm-leg RFP and thorax-leg RFP were not influenced. Conclusions:When velocity was increased, the body increased the spine rotation to keep the balance with the increase of legs rotation. When arms swing constrained, the thorax-spine TRA, lumbar-spine TRA, spine TRA and leg TRA were decreased, so the angular momentum and torque of upper body were decreased. The leg reduced the rotation to keep the balance with upper body. The arm swing drived the thorax rotation to some extent. When arms were constrained the thorax-pelvis RFP became more in-phase, and thorax-pelvis RFP didn't increase with speed increased at this time. And the thorax-spine rotation cannot become out of phase with velocity increasing as normal. The arm-leg rotation was always "out of phase" and not influenced by arms swing. So the arms swing plays an important role in the coordination of trunk movement. The arms swing should be considered and analyzed as an important factor in biomechanical experiments.