Aquatic Testing, Training and Research Unit, Australian Institute of Sport, Canberra, Australia.
Int J Sports Physiol Perform. 2014 Jul;9(4):633-6. doi: 10.1123/ijspp.2013-0205. Epub 2013 Oct 23.
Time trials are commonly used in the lead-up to competition. A method that evaluates the relationship between time trial and competition performance in swimming would be useful for developing performance-enhancement strategies.
To use linear mixed modeling to identify key parameters that can be used to relate time-trial and competition performance.
Ten swimmers participated in the study. Each swimmer was analyzed during 3 time trials and 1 competition. Race video footage was analyzed to determine several key parameters. Pooling of strokes and distances was achieved by modeling changes in parameters between time trials and competition within each subject as linear predictors of percent change in performance using mixed modeling of log-transformed race times.
When parameters were evaluated as the effect of 2 SD on performance time, there were very large effects of start time (2.6%, 90% confidence interval 1.8-3.3%) and average velocity (-2.3%, -2.8% to -1.8%). There was also a small effect for stroke rate (-0.6%, -1.3% to 0.2%). Further analysis revealed an improvement in performance time of 2.4% between time trials and competition, of which 1.8% (large; 1.4-2.1%) was due to a change in average velocity and 0.9% (moderate; 0.6-1.1%) was due to a change in start time; changes in remaining parameters had trivial effects on performance.
This study illustrates effective analytical strategies for identifying key parameters that can be the focus of training to improve performance in small squads of elite swimmers and other athletes.
在比赛前的准备阶段，计时赛通常被广泛应用。如果有一种方法可以评估游泳计时赛成绩与比赛表现之间的关系，那么这种方法将有助于制定提高表现的策略。
使用线性混合建模来确定可以用来关联计时赛和比赛表现的关键参数。
10 名游泳运动员参加了这项研究。每位游泳运动员在 3 次计时赛和 1 次比赛中接受了分析。通过对比赛视频进行分析，确定了几个关键参数。通过混合建模对泳姿和距离进行了整合，以每个个体的线性预测器为模型，将计时赛和比赛中参数的变化作为表现百分率变化的线性预测器，对其进行了对数转换的比赛时间的混合建模。
当参数被评估为对表现时间有 2 个标准差的影响时，出发时间（2.6%，90%置信区间为 1.8%-3.3%）和平均速度（-2.3%，-2.8%至-1.8%）的影响非常大。划频也有较小的影响（-0.6%，-1.3%至 0.2%）。进一步的分析显示，在计时赛和比赛之间，表现时间提高了 2.4%，其中 1.8%（大；1.4-2.1%）是由于平均速度的变化，0.9%（中；0.6-1.1%）是由于出发时间的变化；其余参数的变化对表现的影响微不足道。
本研究说明了有效的分析策略，可用于确定关键参数，这些参数可以成为提高精英游泳运动员和其他运动员小团体表现的训练重点。
