Footwear bending stiffness is known to positively affect performance in agility maneuvers due to improved energy storage and propulsion based on a stiffer foot-shoe complex. However, the functional properties of the forefoot and midfoot differ. Therefore, the present study investigates the effect of the interface of longitudinal bending stiffness and the ratio of forefoot to midfoot bending stiffness on agility performance and foot biomechanics. A total of 18 male soccer players performed 2 agility tasks in footwear conditions that were systematically modified in forefoot and midfoot bending stiffness. Results revealed that higher longitudinal bending stiffness caused more foot exorotation at the initial ground contact (P < .05), less torsion (P < .001), and an anterior shift in the point of force application during push off (P = .01). In addition, the authors observed decreased forefoot bending (P < .05) and increased torsion (P < .01) in footwear with a higher forefoot-midfoot ratio. Finally, the agility performance was significantly impaired by 1.3% in the condition with the highest forefoot-midfoot ratio (P < .01). The high forefoot-midfoot ratio, that is, a stiff forefoot in combination with a soft midfoot, seemed to shift the flex line from anterior to posterior that may explain the performance impairment.

中文翻译：

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前足和中足弯曲刚度对足球敏捷性和足部生物力学的影响。

众所周知，鞋类的弯曲刚度会对敏捷性操作的性能产生积极影响，因为基于更硬的脚-鞋复合体改进了能量存储和推进力。然而，前足和中足的功能特性不同。因此，本研究研究了纵向弯曲刚度界面和前足与中足弯曲刚度之比对敏捷性和足部生物力学的影响。共有 18 名男子足球运动员在鞋类条件下执行了 2 项敏捷性任务，这些任务的前足和中足弯曲刚度进行了系统修改。结果显示，较高的纵向弯曲刚度会导致足部在初始接触地面时发生更多的外旋 (P < .05)、更少的扭转 (P < .001) 以及推出过程中施力点的前移 (P = .01) ）。此外，作者还观察到，前足与中足比例较高的鞋类中，前足弯曲减少 (P < .05)，扭转增加 (P < .01)。最后，在前足与中足比例最高的情况下，敏捷性表现显着受损 1.3% (P < .01)。高前足-中足比率，即僵硬的前足与柔软的中足相结合，似乎将屈线从前部转移到后部，这可能解释了性能障碍。