What pacing strategy 800m and 1500m swimmers use?

Abstract Pacing strategy (PS) has a decisive impact on performance, especially on long-term races.The objective of this study is to characterize the PS used in swimming races of 800m and 1500m freestyle by the finalists of the Olympic trials of the United States, Europe and Brazil,and the Olympic finalists of 2016.Time partials of 63 athletes were analyzed using a decision tree and the CHAID method. The results showed that parabolic was adopted by swimmers of 800m, they start in first lap (29.67 ± 0.88 s), followed by an increase in time (+1.77 s) and a subsequent increase in time (32.04 ± 0.89 s), at the end, the swimmers presented an acceleration,reducing the average of the to 31.44 s. And by the free 1500m swimmers, divided into blocks with a faster average start (29.25 ± 1.15 s), half of the slowest race (30.30 ± 0.76 s), and a new acceleration at the end of the event (29.92 ± 1.12 s), both in the selective Olympic Games and the 2016 and 2016 Olympic final.The worst partials times were observed in the Brazilian Selective (Test Event) (31.11 ± 0.78 s). Medalist, despite presetting the same OS, can sustain a better rhythm throughout he 800m (31.52 ± 1.03 s) and 1500-m (29.80 ± 0.78). We conclude that parabolic PS is the optimal strategy adopted by swimmers of 800-m and 1500m freestyle.

摘要 配速策略（Pacing Strategy, PS）对运动表现具有决定性影响，尤其在长距离赛事中。本研究旨在刻画美、欧、巴西奥运选拔赛及2016年奥运会决赛选手在800米与1500米自由泳赛事中采用的配速策略特征。本研究采用决策树与卡方自动交互检测（CHAID, Chi-squared Automatic Interaction Detector）方法，对63名运动员的分段计时数据进行分析。结果显示，800米自由泳选手普遍采用抛物线型配速策略：首圈耗时为29.67±0.88秒，随后用时增加1.77秒，后续单圈耗时升至32.04±0.89秒；最终选手会发起冲刺加速，将平均单圈耗时降至31.44秒。而1500米自由泳选手则采用分段配速模式：初始阶段平均耗时更快（29.25±1.15秒），中间最慢阶段的单圈耗时为30.30±0.76秒，赛事尾声会再次发起冲刺加速（29.92±1.12秒），该模式在奥运选拔赛及2016年奥运会决赛选手群体中均存在。巴西奥运选拔赛（测试赛）的分段计时成绩最差，平均单圈耗时为31.11±0.78秒。尽管奖牌得主采用的配速策略与其他选手一致，但他们在全程800米自由泳（31.52±1.03秒）与1500米自由泳赛事中能够维持更稳定的节奏，1500米项目平均单圈耗时为29.80±0.78秒。本研究最终得出结论：抛物线型配速策略是800米与1500米自由泳选手的最优配速方案。