Swimming is a challenging locomotion, involving the coordination of upper and lower limbs to propel the body forward in a highly resistive aquatic environment. During front crawl, freestyle stroke, alternating rotational motion of the upper limbs above and below the waterline, is coordinated with alternating lower limb pendulum actions. The aim of this study was to investigate the upper to lower limbs coordination dynamics of eight male elite front crawlers while increasing swimming speed and disturbing the aquatic environment (i.e., pool vs. flume). Upper to lower limb frequency ratios, coordination, coupling strength, and asymmetry were computed from data collected by inertial measurement units. Significant speed effect was observed, leading to transitions from 1∶1 to 1∶3 frequency ratios (1∶3 overrepresented), whereas 1∶2 frequency ratio was rarely used. Flume swimming led to a significant lower coupling strength at low speeds and higher asymmetries, especially at the highest speeds, probably related to the flume dynamic environment.

中文翻译：

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游泳中上肢和下肢的协调动力学取决于游泳速度和水生环境操作。

游泳是一项具有挑战性的运动，涉及上肢和下肢的协调，以在高抵抗力的水生环境中推动身体前进。在前爬泳期间，自由泳冲程，水线上方和下方的上肢交替旋转运动与下肢交替摆动动作协调。这项研究的目的是研究八名男性精英前爬虫的上肢至下肢协调动力学，同时提高游泳速度并扰乱水生环境（即水池与水槽）。从惯性测量单元收集的数据中计算出上肢与下肢的频率比，协调性，耦合强度和不对称性。观察到明显的速度效应，导致从1∶1到1∶3的频率比过渡（过高的1∶3），而很少使用1∶2的频率比。水槽游动导致低速时的显着降低的耦合强度和较高的非对称性，尤其是在最高速度时，这可能与水槽动态环境有关。