Koyama Keiji, Yamauchi Junichiro
Department of Sport Technology, Toin University of Yokohama, Kanagawa, Japan; Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan.
Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan; Future Institute for Sport Sciences, Tokyo, Japan; Research Center in Back, Neck, Other Joint Pain and Human Performance (BNOJPH), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.
J Biomech. 2018 Mar 1;69:47-53. doi: 10.1016/j.jbiomech.2018.01.011. Epub 2018 Jan 12.
This study was to investigate the acute effects of wearing shoes on lower limb kinetics, kinematics and muscle activation during a drop jump. Eighteen healthy men performed a drop jump under barefoot and shod conditions. Vertical ground reaction force (GRF) was measured on a force plate during the contact phase of a drop jump, and GRF valuables were calculated for each condition. The angles of the knee and ankle joints, and the foot strike angle (the angle between the plantar surface of the foot and the ground during ground contact) as well as the electromyography of 7 muscles were measured. The shod condition showed a significant larger first peak GRF, longer time to first peak GRF from the initial ground contact and lower initial loading rate than the barefoot condition. The shod condition showed a significant larger ankle joint angle at initial ground contact, smaller knee joint angle between the second peak GRF and take-off as well as smaller foot strike angle at both initial ground contact and take-off than the barefoot condition. There were significant correlations between relative differences in ankle joint at the initial ground contact and relative differences in the initial loading rate. The muscle activity of all muscles during foot ground contact did not differ between two conditions; however, in the shod condition, muscle activation of 150 ms before foot ground contact was significantly higher in the rectus femoris, whereas it was lower in the biceps femoris and tibialis anterior muscles than the barefoot condition. These results indicate that wearing shoes alternates the GRF variables at initial ground contact, joint kinematics at the ground contact and muscle activation before foot ground contact during a drop jump, suggesting that the effects of wearing shoes on drop jump training differ from being barefoot.
本研究旨在探讨穿鞋对下落跳过程中下肢动力学、运动学和肌肉激活的急性影响。18名健康男性在赤脚和穿鞋条件下进行下落跳。在下落跳的接触阶段，通过测力台测量垂直地面反作用力（GRF），并计算每种条件下的GRF值。测量膝关节和踝关节的角度、足着地角度（地面接触时足底与地面之间的角度）以及7块肌肉的肌电图。与赤脚条件相比，穿鞋条件下首次峰值GRF显著更大，从初始地面接触到首次峰值GRF的时间更长，初始加载率更低。与赤脚条件相比，穿鞋条件下初始地面接触时踝关节角度显著更大，第二次峰值GRF与起跳之间的膝关节角度更小，初始地面接触和起跳时的足着地角度更小。初始地面接触时踝关节的相对差异与初始加载率的相对差异之间存在显著相关性。两种条件下，足部与地面接触期间所有肌肉的活动无差异；然而，在穿鞋条件下，足部与地面接触前150毫秒时，股直肌的肌肉激活显著高于赤脚条件，而股二头肌和胫骨前肌的肌肉激活则低于赤脚条件。这些结果表明，穿鞋会改变下落跳过程中初始地面接触时的GRF变量、地面接触时的关节运动学以及足部与地面接触前的肌肉激活，这表明穿鞋对下落跳训练的影响与赤脚不同。
