DURATION AND QUALITY OF SLEEP IN SPRINT AND RECOVERY PERFORMANCES AMONG ELITE SWIMMERS

ABSTRACT Introduction: Circadian rhythms can impact athletes' sports performance, where the plateau occurs between 15 and 21 hours. Swimming is a peculiar case, as athletes perform training and final sessions in competitions at different times, as in the Rio2016 Olympic Games for example, where the semifinal and final competitions took place from ten o'clock at night. Objectives: (1) to present the protocol of an intervention performed with elite athletes of the Brazilian swimming team during the 2016 Olympic Games in Rio; (2) to find out whether the time at which the competitions were held affected the swimming performances of these athletes during the competition. Materials and Methods: Fourteen athletes of the Brazilian swimming team (males: n= 10; 71% and females: n= 4; 29%) participated in the study. They were followed up during two preparation periods (baseline and intervention) for the 2016 Olympic Games in Rio during June and July 2016. During the competition, we recorded the Reaction Time (RT) and Competition Time (CT) of each athlete in different modalities. The intervention strategies used were light therapy and sleep hygiene. The values of RT at the starting block and CT were registered and conferred with the official results. Results: The athletes showed a decrease in the total time awake (Δ = −13%; Effect size [ES] = 1.0) and sleep latency (Δ = −33%; ES = 0.7), and an increase in total sleep time (Δ = 13%; ES = 1.1; p = 0.04) between the baseline and the period of the intervention, pre-competition. We identified an improvement in the RT (Δ = −2.2% to −1.0%; ES = 0.2 to 0.5) during the competition only for the athletes who participated in the competition finals. Conclusion: We conclude that the intervention carried out was effective in mitigating any negative influence of competition time on the RT and CT of elite athletes of the Brazilian swimming team. Level of evidence II; Prospective comparative study.

摘要：引言：昼夜节律可影响运动员的运动表现，其性能平台期通常出现在15时至21时之间。游泳项目则属于特殊案例，运动员的训练及赛事决赛时段往往存在差异——以2016年里约奥运会为例，该赛事的半决赛与决赛均安排在夜间十点进行。研究目标：（1）介绍2016年里约奥运会期间针对巴西游泳队精英运动员实施的干预方案；（2）探究赛事举办时段是否对该批次运动员的比赛游泳成绩产生影响。研究对象与方法：本研究纳入14名巴西游泳队精英运动员（男运动员10名，占比71%；女运动员4名，占比29%）。研究于2016年6-7月开展，在2016年里约奥运会备战阶段分为基线期与干预期两个阶段对受试者进行追踪。赛事期间，我们记录了不同泳姿项目下每位运动员的反应时（Reaction Time, RT）与比赛用时（Competition Time, CT）。本次干预采用光照疗法与睡眠卫生指导两种策略。出发台反应时与比赛用时数据经登记后，与赛事官方成绩进行了核对。研究结果：相较于基线期，赛前干预阶段运动员的总清醒时长（Δ=-13%；效应量[ES]=1.0）与睡眠潜伏期（Δ=-33%；ES=0.7）均显著缩短，总睡眠时间则显著增加（Δ=13%；ES=1.1；p=0.04）。仅在进入决赛的运动员中，赛事期间的反应时得到改善（Δ=-2.2%~-1.0%；ES=0.2~0.5）。研究结论：本次实施的干预措施可有效缓解赛事时段对巴西游泳队精英运动员反应时与比赛用时的负面影响。证据等级：II级；前瞻性对照研究。