跑跳等落地时，人体下肢所承受的过度被动冲击，以及冲击力频率（10-20Hz）与下肢软组织固有频率（5-65Hz）的重叠而引起的共振，是诱发下肢肌-骨系统损伤的重要因素。而运动鞋针对外在冲击力作为输入人体信号的影响以及疲劳所导致的内在神经肌肉调节能力的变化，均会引起下肢运动系统、软组织振动特征（振幅、频率等）和肌-骨系统激活效应的改变，并最终影响运动表现和冲击共振损伤的发展。本研究拟通过同步采集受试者在跑、跳落地冲击过程中的运动学、动力学、表面肌电、加速度信号和高速影像，探讨神经肌肉疲劳前后运动鞋对冲击力特征、软组织振动传递、下肢关节生物力学及主要肌群活化表现的影响，找寻它们之间的相互关系，在揭示人体疲劳下神经动作控制的同时，更深层次地理解疲劳与运动鞋之间可能存在的交互作用，从而建立运动鞋针对减小冲击、避免共振、优化肌-骨系统功能的新机制，并为预防运动损伤及鞋防护设计奠定理论和技术基础。

During running and landing, injuries or disorders of the skeletal system may theoretically be induced by repetitive impact forces loaded on human lower extremities, and resonant oscillations which are expected to occur if the frequency of the impact force (10-20Hz) is close to the natural frequencies of the lower extremity soft tissues（5-65Hz）. However, the effects of athletic shoe on impact input signal and the changes in regulating the ability of the neuromuscular system induced by fatigue, could both influence the locomotor system, soft-tissue vibration characteristics (frequency and amplitude), and the activation response in the musculoskeletal system. Subsequently, sport performance and impact-related injury can be altered systematically. The purpose of this study is to examine the interaction effects of induced-fatigue and footwear on impact forces, soft-tissue vibrations, and the joint biomechanics & muscle activated patterns in lower extremity by collecting the kinematics, kinetics, EMG & acceleration data, and high-speed videos during running and landing. The findings upon this study will be used to 1) further understand the relationship between footwear and fatigue, 2) establish new mechanisms for the effects of footwear on reducing the impacts, avoiding the resonance, and optimizing the musculoskeletal function of lower-extremity, and 3) provide theoretical basis and technological supports in injury prevention and shoe design.