Yamakawa Keisuke Kobayashi, Homoto Kenta, Nakashima Motomu, Shimojo Hirofumi, Nakazono Yusaku, Sengoku Yasuo, Takagi Hideki
Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
Department of Sports and Health Science, Japan Women's College of Physical Education, Setagaya, Japan.
Sports Biomech. 2025 Jan 30:1-16. doi: 10.1080/14763141.2025.2458473.
It is well-known among swimmers and coaches that the swimming speed of the underwater dolphin kick (UDK) is higher than that of the underwater flutter kick (UFK). This study aimed to clarify the differences in swimming performance between the two kicking styles in terms of kinematics, kinetics and muscle activity. Eight male swimmers performed UDK and UFK in a water flume at same effort levels. The three-dimensional motion analysis and measurement of surface electromyography for the left lower limb were performed. The fluid forces acting on the body and joint torques were estimated using Swumsuit simulator. As the results, the kick amplitude and range of joint motion were smaller for the UFK than for the UDK, and the muscle activity and the peak joint torques of the hip and knee were lower for the UFK than for the UDK. Furthermore, the estimated propulsion for both the downward and upward kicks was lower for the UFK than for the UDK. Therefore, our results suggest that the differences in propulsion between the two kicking styles, caused by the differences in movement and muscle activity, may influence the differences in swimming speed.
游泳运动员和教练都熟知，水下海豚腿（UDK）的游泳速度高于水下鞭状踢腿（UFK）。本研究旨在从运动学、动力学和肌肉活动方面阐明两种踢腿方式在游泳表现上的差异。八名男性游泳运动员在水槽中以相同的用力水平进行UDK和UFK动作。对左下肢进行了三维运动分析和表面肌电图测量。使用泳衣模拟器估算作用于身体的流体动力和关节扭矩。结果显示，UFK的踢腿幅度和关节运动范围小于UDK，UFK的肌肉活动以及髋部和膝部的峰值关节扭矩低于UDK。此外，UFK向下和向上踢腿的估算推进力均低于UDK。因此，我们的结果表明，两种踢腿方式之间由运动和肌肉活动差异导致的推进力差异，可能会影响游泳速度的差异。
