Background

Several studies compared African runners with runners from other places with difference ethnicities to identify biomechanical factors that may contribute to their extraordinary running performance. However, most studies only assessed runners at the elite level. Whether the performance difference was a result of nature or nurture remains unclear.

Research questions

This case study aimed to assess the effect of geographical origin and the effect of training on running biomechanics.

Methods

We recruited twenty male runners from two regions (Asian and Africa) at two performance levels (elite and recreational), and asked them to run on an instrumented treadmill at 12 km∙h⁻¹. We measured running kinetics and kinematics parameters, and focused on the parameters that have been shown associated with running performance. We used Friedman test to compare the effect of geographical origin and training on running biomechanics.

Results

Compared to recreational runners, elite runners applied higher amount of ground reaction force in both vertical and anterior-posterior directions (P < 0.05, Cohen’s d = 1.63–2.03), together with a longer aerial time (P = 0.039, Cohen’s d = 1.11). On the other hand, African runners expressed higher vertical stiffness than Asian runners (P = 0.027, Cohen’s d = 0.98). However, the increased vertical stiffness in African runners did not lead to a higher vertical loading rate (P > 0.555, Cohen’s d < 0.3), which could be a result of a lower footstrike angle during landing (P = 0.012, Cohen’s d = 1.36).

Significance

For elite runners, the higher amount of ground reaction force might facilitate a longer aerial time, but could also lead to higher amount of mechanical energy loss. African runners expressed higher vertical stiffness and higher step rate, which might lead to a lower CoM vertical displacement, and furthermore reduce mechanical energy loss.

中文翻译：

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跑步者的训练经验和地理位置如何影响跑步的生物力学？

背景

几项研究将非洲跑步者与其他地区种族不同的跑步者进行了比较，以确定可能有助于其出色跑步表现的生物力学因素。但是，大多数研究只评估精英水平的跑步者。性能差异是自然还是养育的结果尚不清楚。

研究问题

本案例研究旨在评估地理起源的影响以及培训对运行生物力学的影响。

方法

我们从两个地区（精英级和娱乐级）招募了来自两个地区（亚洲和非洲）的二十名男性跑步者，并请他们在12 km∙h ^-1的带器械的跑步机上跑步。我们测量了跑步动力学和运动学参数，并重点研究了与跑步性能相关的参数。我们使用弗里德曼（Friedman）检验来比较地理起源和培训对跑步生物力学的影响。

结果

与休闲跑步者相比，精英跑步者在垂直和前后方向上都施加了更大的地面反作用力（P  <0.05，Cohen's d  = 1.63-2.03），同时飞行时间更长（P  = 0.039，Cohen's d  = 1.11） ）。另一方面，非洲跑步者表现出比亚洲跑步者更高的垂直刚度（P  = 0.027，Cohen d  = 0.98）。但是，非洲跑步者增加的垂直刚度并不会导致更高的垂直负荷率（P  > 0.555，Cohen d <0.3），这可能是降落过程中较低的脚部打击角（P  = 0.012，Cohen d = 1.36）。

意义

对于精英跑步者而言，较高的地面反作用力可能会有助于延长飞行时间，但也可能导致较高的机械能损耗。非洲选手表现出更高的垂直刚度和更高的步速，这可能导致更低的CoM垂直位移，并进一步减少机械能的损失。