Foot strike patterns influence the running efficiency and may be an injury risk. However, differences in the leg stiffness between runners with habitual forefoot (hFFS) and habitual rearfoot (hRFS) strike patterns remain unclear. This study aimed at determining the differences in the stiffness, associated loading rate, and kinematic performance between runners with hFFS and hRFS during running. Kinematic and kinetic data were collected amongst 39 runners with hFFS and 39 runners with hRFS running at speed of 3.3 m/s, leg stiffness (Kleg), and vertical stiffness (Kvert), and impact loads were calculated. Results found that runners with hFFS had greater Kleg (, ), greater peak vertical ground reaction force (vGRF) (, ), shorter contact time() (, ), and smaller maximum leg compression () (, ) compared with their hRFS counterparts. Runners with hFFS had lower impact peak (IP) (, ), vertical average loading rate (VALR) (, ), and vertical instantaneous loading rate (VILR) (, ) compared with runners with hRFS. Runners with hFFS landed with a plantar flexed ankle, whereas runners with hRFS landed with a dorsiflexed ankle (, ). Runners with hFFS also exhibited more flexed hip (, ) and knee (, ) than runners with hRFS at initial contact. These results might indicate that runners with hFFS were associated with better running economy through the transmission of elastic energy.

中文翻译：

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习惯性前脚掌和后脚掌的跑步者腿部刚度和垂直刚度

脚部踩踏方式会影响跑步效率，并且可能会造成人身伤害。然而，习惯性前脚（hFFS）和习惯性后脚（hRFS）攻击方式的跑步者之间的腿部僵硬差异尚不清楚。这项研究旨在确定在跑步过程中具有hFFS和hRFS的跑步者之间的刚度，相关负荷率和运动学性能的差异。收集了39个具有hFFS的跑步者和39个hRFS的跑步者以3.3 m / s的速度，腿部刚度（Kleg）和垂直刚度（Kvert）运行的运动和动力学数据，并计算了冲击载荷。结果发现，携带hFFS的跑步者的Kleg（， ），更大的垂直地面反作用力峰值（vGRF）（， ），接触时间更短（）（， ），并减小最大腿部压力（）（， ）与hRFS同行相比。拥有hFFS的跑步者的冲击峰值（IP）较低（， ），垂直平均装载率（VALR）（， ）和垂直瞬时荷载率（VILR）（， ）与具有hRFS的跑步者相比。具有hFFS的跑步者着地plant屈脚踝，而具有hRFS的跑步者着地背屈脚踝（， ）。携带hFFS的跑步者还表现出更加弯曲的臀部（， ）和膝盖（， ），而不是初次接触时具有hRFS的跑步者。这些结果可能表明，具有hFFS的跑步者通过传递弹性能量而获得了更好的跑步经济性。