>Context: The leg acts as a linear spring during running and hopping and adapts to the stiffness of the surface, maintaining constant total stiffness of the leg-surface system. Introducing a substance (eg, footwear) may affect the stiffness of the leg in response to changes in surface stiffness. >Objective: To determine if the type of athletic footwear affects the regulation of leg stiffness in dynamic activities. >Design: Repeated-measures design. >Setting: Motion analysis laboratory. >Patients or Other Participants: Nine healthy adults (age = 28 ± 6.8 years, mass = 71.6 ± 12.9 kg) free from lower extremity injuries. >Intervention(s): Subjects hopped at 2.2 Hz on a forceplate under 3 footwear conditions (barefoot, low-cost footwear, high-cost footwear). Subjects ran on a treadmill at 2 speeds (2.23 m/s, 3.58 m/s) under the same footwear conditions. >Main Outcome Measure(s): Limb stiffness was calculated from forceplate data. Kinematic data (knee and ankle angles at initial contact and peak joint excursion after contact) were collected during running. We calculated 1-way repeated-measures (stiffness) and 2-way (speed by footwear) repeated-measures analyses of variance (running kinematics) to test the dependent variables. >Results: A significant increase in leg stiffness from the barefoot to the “cushioned” shoe condition was noted during hopping. When running shod, runners landed in more dorsiflexion but had less ankle motion than when running barefoot. No differences were seen between the types of shoes. The primary kinematic difference was identified as running speed increased: runners landed in more knee flexion. At the ankle, barefoot runners increased ankle motion to a significantly greater extent than did shod runners as speed increased. >Conclusions: Footwear influences the maintenance of stiffness in the lower extremity during hopping and joint excursion at the ankle in running. Differences in cushioning properties of the shoes tested did not appear to be significant.
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机译：>上下文：腿部在跑步和跳跃过程中充当线性弹簧，并适应表面的刚度，从而保持腿部曲面系统的总刚度恒定。引入物质（例如鞋类）可能会响应表面刚度的变化而影响腿部的刚度。 >目的：确定运动鞋的类型是否会影响动态活动中腿部僵硬的调节。 >设计：重复测量设计。 >设置：运动分析实验室。 >患者或其他参与者：9位健康的成年人（年龄= 28±6.8岁，体重= 71.6±12.9公斤），没有下肢受伤。 >干预：受试者在3种鞋类条件下（赤脚，低成本鞋类，高价鞋类）在强制板上以2.2 Hz的频率跳动。在相同的鞋类条件下，受试者以2速（2.23 m / s，3.58 m / s）在跑步机上跑步。 >主要结果指标：根据测力板数据计算肢体刚度。在跑步过程中收集运动数据（初次接触时的膝和踝角以及接触后的峰值关节偏移）。我们计算了方差（运行运动学）的1次重复测量（刚度）和2次重复（测量鞋类速度）以测试因变量。 >结果：在跳跃过程中，从赤脚状态到“被缓冲”的鞋状态，腿部僵硬度明显增加。跑步时，与赤脚跑步相比，跑步者的背屈更大，但脚踝运动更少。鞋子类型之间没有差异。运动学上的主要差异被确定为跑步速度的提高：跑步者的膝盖屈曲幅度更大。在脚踝处，随着速度的增加，赤脚跑步者增加脚踝运动的程度要比长跑者增加得多。>结论：鞋类在跑步过程中会影响下肢僵硬的保持和脚踝关节偏移。所测试的鞋子在缓冲性能上的差异似乎并不明显。
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