Narita Kenzo, Nakashima Motomu, Takagi Hideki
Doctoral Program in Physical Education, Health and Sport Sciences, University of Tsukuba, Japan.
Department of Systems and Control Engineering, Tokyo Institute of Technology, Japan.
J Biomech. 2017 Mar 21;54:123-128. doi: 10.1016/j.jbiomech.2017.01.037. Epub 2017 Feb 10.
We aimed to develop a new method for evaluating the drag in front-crawl swimming at various velocities and at full stroke. In this study, we introduce the basic principle and apparatus for the new method, which estimates the drag in swimming using measured values of residual thrust (MRT). Furthermore, we applied the MRT to evaluate the active drag (Da) and compared it with the passive drag (Dp) measured for the same swimmers. Da was estimated in five-stages for velocities ranging from 1.0 to 1.4ms; Dp was measured at flow velocities ranging from 0.9 to 1.5ms at intervals of 0.1ms. The variability in the values of Da at MRT was also investigated for two swimmers. According to the results, Da (Da=32.3 v, N=30, R=0.90) was larger than Dp (Dp=23.5 v, N=42, R=0.89) and the variability in Da for the two swimmers was 6.5% and 3.0%. MRT can be used to evaluate Da at various velocities and is special in that it can be applied to various swimming styles. Therefore, the evaluation of drag in swimming using MRT is expected to play a role in establishing the fundamental data for swimming.
我们旨在开发一种新方法，用于评估自由泳在不同速度和完整划水时的阻力。在本研究中，我们介绍了这种新方法的基本原理和装置，该方法利用测量的剩余推力（MRT）值来估算游泳时的阻力。此外，我们应用MRT来评估主动阻力（Da），并将其与同一游泳者测量的被动阻力（Dp）进行比较。在速度范围为1.0至1.4米/秒的情况下，分五个阶段估算Da；在流速范围为0.9至1.5米/秒、间隔为0.1米/秒的条件下测量Dp。还研究了两名游泳者在MRT时Da值的变异性。根据结果，Da（Da = 32.3v，N = 30，R = 0.90）大于Dp（Dp = 23.5v，N = 42，R = 0.89），两名游泳者Da的变异性分别为6.5%和3.0%。MRT可用于评估不同速度下的Da，其特别之处在于可应用于各种游泳姿势。因此，利用MRT评估游泳阻力有望在建立游泳基础数据方面发挥作用。
