Department of Rehabilitation and Sport Sciences, Bournemouth University, Poole, UK.
Department of Physical Performance, Norwegian School of Sport Sciences, Ullevål Stadion, Postboks 4014, 0806, Oslo, Norway.
Sci Rep. 2022 Jul 29;12(1):13085. doi: 10.1038/s41598-022-17415-5.
The purpose of the presents study was to investigate the reliability of the active drag (D) assessment using the velocity perturbation method (VPM) with different external resisted forces. Eight male and eight female swimmers performed 25 m sprints with five isotonic loads (1-2-3-4-5 kg for females; 1-3-5-7-9 kg for males), which were repeated twice on different days. The mean velocity and semi-tethered force were computed for each condition, and the free-swimming maximum velocity was estimated with load-velocity profiling. From the obtained variables, D at the maximum free-swimming condition was calculated using VPM. Absolute and typical errors and the intra-class correlation (ICC) were calculated to assess test-retest reliability. 95% confidence interval (95% CI) lower bound of ICC was larger than 0.75 in 3, 4 (females only) and 5 kg trials in both sexes (corresponding to 37-60 N additional resistance; all p < 0.001), which also showed small absolute and relative typical errors (≤ 2.7 N and ≤ 4.4%). In both sexes, 1 kg load trial (16-17 N additional resistance) showed the lowest reliability (95% CI of ICC; - 0.25-0.83 in males and 0.07-0.94 in females). These results suggested that a tethered force of 37-60 N should be used to assess D using VPM.
本研究的目的是探讨使用速度干扰法（VPM）评估主动阻力（D）的可靠性，以及在不同外部阻力下的可靠性。八名男性和八名女性游泳运动员进行了 25 米冲刺，分别施加了五种等速负荷（女性为 1-2-3-4-5 公斤；男性为 1-3-5-7-9 公斤），在不同的两天内重复两次。对每种条件下的平均速度和半束缚力进行了计算，并使用负荷-速度曲线估计了自由泳的最大速度。从获得的变量中，使用 VPM 计算最大自由泳条件下的 D。绝对误差和典型误差以及组内相关系数（ICC）用于评估测试-重测可靠性。在男性和女性的 3、4（仅女性）和 5 公斤试验中，ICC 的 95%置信区间（95%CI）下限均大于 0.75（相应的附加阻力为 37-60 N；所有 p < 0.001），并且还显示出较小的绝对和相对典型误差（≤2.7 N 和 ≤4.4%）。在两性中，1 公斤负荷试验（16-17 N 附加阻力）的可靠性最低（ICC 的 95%CI；男性为-0.25-0.83，女性为 0.07-0.94）。这些结果表明，应使用 37-60 N 的束缚力来使用 VPM 评估 D。
