Lees Adrian, Lake Mark, Klenerman Leslie
Liverpool John Moores University, Sport and Exercise Sciences, Henry Cotton Campus, Webster Street, Liverpool L3 2ET, United Kingdom.
Foot Ankle Int. 2005 Dec;26(12):1081-8. doi: 10.1177/107110070502601214.
Overuse injuries to the lower extremity have often been connected with the repetitive loading of the foot and in particular its ability to absorb shock. The shock absorbing ability of the foot is thought to relate to its structure, particularly the height of the medial longitudinal arch. The purpose of this study was to investigate the shock absorption characteristics of the foot in forefoot running as measured by the dynamic load rate of the vertical ground reaction forces during the early stages of ground contact and to relate these characteristics to the height of the medial longitudinal arch.
Eighteen normal athletic adult volunteers were used as subjects and all had clinically normal feet. An Arch Index was computed from lateral radiographs taken with the foot in a full weightbearing position. Dynamic load rate was computed as the first differential of the vertical force as measured by a Kistler force platform. Each subject performed ten trials of running at a speed of 3 m.s-1 using forefoot running style.
The dynamic load rate showed three definite peaks (mean 93, 18, and 16 kNs-1 respectively), and two intervening troughs (mean 18 and 3 kNs-1 respectively), showing that the process of shock absorption was one that was progressive over the foot loading phase. The time at which these features occurred indicated a consistency in process of shock absorption. However, none of the force peaks or load rate peaks correlated with the Arch Index.
It was concluded that the structure of the foot as characterized by the Arch Index, was not the major factor in determining the way in which force is transmitted to the musculoskeletal system in forefoot running. These findings support the concept that the height of the arch, although a commonly used clinical descriptor of foot type does not appear to be important in defining the functional capacity of the foot in action.
下肢过度使用损伤常与足部的重复性负荷，尤其是其吸收冲击的能力有关。足部的减震能力被认为与其结构有关，特别是内侧纵弓的高度。本研究的目的是通过测量着地初期垂直地面反作用力的动态负荷率，来研究前脚掌跑步时足部的减震特性，并将这些特性与内侧纵弓的高度联系起来。
18名正常的成年运动员志愿者作为受试者，他们的足部临床检查均正常。通过在足部完全负重位置拍摄的侧位X线片计算足弓指数。动态负荷率通过Kistler测力平台测量的垂直力的一阶导数来计算。每个受试者以3m·s-1的速度采用前脚掌跑步方式进行10次跑步试验。
动态负荷率显示出三个明确的峰值（分别平均为93、18和16kN·s-1）和两个中间低谷（分别平均为18和3kN·s-1），表明减震过程是一个在足部加载阶段逐渐进行的过程。这些特征出现的时间表明减震过程具有一致性。然而，力峰值或负荷率峰值均与足弓指数无关。
得出的结论是，以足弓指数为特征的足部结构，不是决定前脚掌跑步时力传递到肌肉骨骼系统方式的主要因素。这些发现支持了这样一种观点，即足弓高度虽然是常用的足部类型临床描述指标，但在定义足部实际功能能力方面似乎并不重要。
