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. RESUMO Introdução: Os ritmos circadianos podem exercer impacto no desempenho esportivo dos atletas, onde o platô ocorre entre as 15 e 21 horas. A natação é um caso peculiar, uma vez que os nadadores realizam sessões de treinamento e provas finais em competições em diferentes horários, como por exemplo, nos Jogos Olímpicos Rio2016, onde as competições semifinais e finais da natação ocorreram a partir das 22 horas. Objetivos: O presente estudo teve como objetivos: (1) apresentar o protocolo de uma intervenção realizada com atletas de elite da