Department of Health and Sports, Niigata University of Health and Welfare, Niigata, Japan.
J Sports Sci. 2021 Jul;39(13):1497-1503. doi: 10.1080/02640414.2021.1881313. Epub 2021 Feb 17.
The present study was conducted to identify the kinematic variables associated with dolphin kick performance during the acceleration and deceleration phases. Nine male competitive swimmers performed 3-5 × 15-m dolphin kick swimming trials with maximum effort. The underwater motion of the dolphin kick was recorded using a digital video camera for a two-dimensional motion analysis. Upper-lower trunk and leg angles in addition to shoulder, hip, and knee joint angles were calculated as kinematic variables. The average horizontal velocity of the greater trochanter during two cycles of the dolphin kick correlated with the angular displacement of the lower trunk in the acceleration (r = -0.715, p < 0.05) and deceleration phases (r = 0.682, p < 0.05). Furthermore, greater angular displacement of the lower trunk was associated with smaller angular displacement of the upper leg and greater angular displacement of the hip, knee, and lower leg in both phases. These results suggest that the movement of the lower trunk is a key kinematic variable for dolphin kick performance, and also that swimming coaches and swimmers need to focus on the movement of the lower trunk as well as upper-lower legs in order to improve dolphin kick motion.
本研究旨在确定海豚踢加速和减速阶段与海豚踢表现相关的运动学变量。9 名男性竞技游泳运动员用最大努力进行了 3-5 次 15 米海豚踢游泳试验。使用数字摄像机记录海豚踢的水下运动，以进行二维运动分析。计算了上肢-下肢角度以及肩部、臀部和膝关节角度等运动学变量。在海豚踢的两个周期中，大转子的平均水平速度与加速（r=-0.715，p<0.05）和减速（r=0.682，p<0.05）阶段下肢的角位移相关。此外，在两个阶段中，下肢的较大角位移与大腿的较小角位移和髋、膝、小腿的较大角位移相关。这些结果表明，下肢的运动是海豚踢表现的关键运动学变量，游泳教练和游泳运动员需要关注下肢以及上下肢的运动，以改善海豚踢动作。
