Barbosa T M, Morais J E, Marques M C, Silva A J, Marinho D A, Kee Y H
National Institute of Education, Nanyang Technological University, Singapore, Singapore; Research Centre in Sports, Health and Human Development, Vila Real, Portugal.
Scand J Med Sci Sports. 2015 Apr;25(2):e184-96. doi: 10.1111/sms.12281. Epub 2014 Jun 27.
The aim of this study was to analyze the changes in the hydrodynamic profile of young swimmers over a competitive season and to compare the variations according to a well-designed training periodization. Twenty-five swimmers (13 boys and 12 girls) were evaluated in (a) October (M1); (b) March (M2); and (c) June (M3). Inertial and anthropometrical measures included body mass, swimmer's added water mass, height, and trunk transverse surface area. Swimming efficiency was estimated by the speed fluctuation, stroke index, and approximate entropy. Active drag was estimated with the velocity perturbation method and the passive drag with the gliding decay method. Hydrodynamic dimensionless numbers (Froude and Reynolds numbers) and hull velocity (i.e., speed at Froude number = 0.42) were also calculated. No variable presented a significant gender effect. Anthropometrics and inertial parameters plus dimensionless numbers increased over time. Swimming efficiency improved between M1 and M3. There was a trend for both passive and active drag increase from M1 to M2, but being lower at M3 than at M1. Intra-individual changes between evaluation moments suggest high between- and within-subject variations. Therefore, hydrodynamic changes over a season occur in a non-linear fashion way, where the interplay between growth and training periodization explain the unique path flow selected by each young swimmer.
本研究的目的是分析年轻游泳运动员在一个竞技赛季中的水动力特征变化，并根据精心设计的训练周期安排比较这些变化。对25名游泳运动员（13名男孩和12名女孩）在（a）10月（M1）；（b）3月（M2）；以及（c）6月（M3）进行了评估。惯性和人体测量指标包括体重、游泳者的附加水质量、身高和躯干横截面积。游泳效率通过速度波动、划水指数和近似熵来估计。主动阻力用速度扰动法估计，被动阻力用滑行衰减法估计。还计算了水动力无量纲数（弗劳德数和雷诺数）和船体速度（即弗劳德数 = 0.42时的速度）。没有变量呈现出显著的性别效应。人体测量学和惯性参数以及无量纲数随时间增加。游泳效率在M1和M3之间有所提高。从M1到M2，被动和主动阻力都有增加的趋势，但在M3时低于M1。评估时刻之间的个体内变化表明受试者之间和受试者内部存在很大差异。因此，一个赛季中的水动力变化以非线性方式发生，生长和训练周期安排之间的相互作用解释了每个年轻游泳运动员选择的独特路径流。
