Cardiac autonomic nervous activity during different sleep stages in individuals with spinal cord injury: The influence of physical training.

OBJECTIVE: The present study assessed the influence of physical training on cardiac autonomic activity in individuals with spinal cord injury (SCI) during different sleep stages. METHODS: Twenty-six volunteers were allocated into three groups: 9 sedentary individuals without SCI (control, CON); 8 sedentary tetraplegic individuals with chronic SCI (SED-SCI); 9 physically trained tetraplegic individuals with chronic SCI (TR-SCI). All participants underwent nocturnal polysomnography to monitor sleep stages: wakefulness, non-rapid eye movement (NREM) sleep (N1, N2, and N3 stages), and REM sleep. The electrocardiography data obtained during this exam were extracted to analyze the heart rate variability (HRV). RESULTS: Sleep stages influenced HRV in the time [RR interval and root mean square of successive RR interval differences (RMSSD)] and frequency [low-frequency (LF) and high-frequency (HF) powers and LF-to-HF ratio] domains (P < 0.05). SED-SCI individuals showed unchanged HRV compared to CON (P > 0.05). When comparing the TR-SCI and SED-SCI groups, no significant differences in HRV were reported in the time domain (P > 0.05). However, in the frequency domain, more accentuated HF power was observed in TR-SCI than in SED-SCI individuals during the N2 and N3 stages and REM sleep (P < 0.05). Moreover, TR-SCI had higher HF power than CON during the N3 stage (P < 0.05). CONCLUSIONS: TR-SCI individuals have greater HF power, indicative of parasympathetic modulation, than sedentary (injured or not injured) individuals during different sleep stages. Therefore, enhanced parasympathetic activity induced by physical training may improve cardiac autonomic modulation during sleep in individuals with chronic SCI.

The sleep as a predictor of musculoskeletal injuries in adolescent athletes.

Objectives: Sleep is essential for musculoskeletal and cognitive recovery. Adolescent athletes tend to sleep poorly compared to adults and it may predispose them to sports injuries. Our aims are to estimate whether the quantity/quality of sleep are associated with sports injuries in adolescent athletes and to compare the quantity/quality of sleep between the training and competition seasons, and the school vacation period. Material and Methods: It was a cohort study with 19 track and field athletes of both sexes, aged between 12 and 21 years. We evaluated their sleep-wake habit through actigraphy during three phases: 1 - mid-season, 2 - competition, and 3 - school vacation. The previous six months injury history and the occurrence of injuries in a six-month follow-up were recorded. Logistic regression and variance analysis were performed. The significance level used was 0.05. Results: Wake after sleep onset (WASO) predicted previous injuries (OR=1.144) and time awake (TA) predicted injury occurrence (OR=0.974). TA decreased from phase 2 to phase 3 (p=0.004), total sleep time (TST) increased from phase 2 to phase 3 (p=0.012), and WASO decreased between phases 1 and 2 (p=0.001) and between phases 1 and 3 (p=0.025). Conclusion: Our study demonstrated that the quantity and quality of sleep were associated with musculoskeletal injuries in adolescent track and field athletes. Previous injuries were predicted by WASO and the occurrence of injuries was predicted by TA. Furthermore, during the vacation period they had lower TA and WASO, and higher TST than on school days.

Two Years of COVID-19 Pandemic: How the Brazilian Serie A Championship Was Affected by Home Advantage, Performance and Disciplinary Aspects.

As a result of the COVID-19 pandemic, the Brazilian Serie A championship was played without crowds in 2020 and partially in the 2021 season. We verified if the home advantage (HA) was different between the 2018, 2019, 2020, and 2021 seasons. We also compared the HA, performance, and disciplinary aspects between the rounds with or without crowds and verified the association between the number of absent athletes because of health protocols and the HA in the 2020 and 2021 seasons. We calculated the HA using the Pollard method. The performance aspects were goals, corners, shots, and ball possession, and the disciplinary aspects were fouls, yellow cards, and red cards. The HA was higher in the 2018 season compared with the other seasons. The rounds with crowds showed higher HAs than the two previous seasons and the teams had more shots and scored more goals than in the rounds without crowds. There were 457 athletes in the 2020 season and 123 athletes in the 2021 season who were absent because of health protocols, and there was no association between absence and HA. The COVID-19 pandemic affected soccer in the two last seasons in different ways in the Brazilian Serie A championship.

Influência da privação de sono no desempenho de atletas: uma revisão sistemática / The influence of sleep deprivation on athletes' performance: a systematic review

RESUMO O sono é uma estratégia importante para a recuperação de atletas e o estado de privação de sono pode influenciar a performance esportiva. O objetivo do estudo foi realizar uma revisão sistemática de literatura para analisar a influência da privação de sono no desempenho físico e esportivo de atletas. A pesquisa foi realizada a partir das bases de dados eletrônicas PubMed, Scopus, SportDiscus e Scielo. Foram selecionados artigos originais publicados escritos no idioma inglês ou português. Após a busca nas bases de dados foram encontrados 143 artigos sendo 45 no PubMed, 72 no Scopus, 1 no Scielo e 25 no SportDiscus. Posteriormente a análise dos artigos, 8 artigos foram incluídos no presente estudo de acordo com os critérios de inclusão. Após análise dos 8 artigos incluídos na revisão, concluiu-se que a privação de sono influenciou negativamente no desempenho físico e esportivo em 5 dos artigos analisados. Além disso, constatou-se que o período de privação de sono é determinante para o desempenho dos atletas nas tarefas esportivas.

ABSTRACT Sleeping is an important strategy for athletes' recovery and the state of sleep deprivation can influence the sports performance.The objective of the study was to carry out a systematic literature review in order to analyze the influence of sleep deprivation on the physical and athletic performance of athletes. The study was carried out from the electronic databases PubMed, Scopus, SportDiscus and Scielo. We selected original articles published and written in English or Portuguese were selected. After the search in the databases we found 143 articles were found being 45 from PubMed, 72 from Scopus, 1 from Scielo and 25 from SportDiscus. After the full analysis of the articles, only 8 of them articles were included in the present study according to the inclusion criteria. After analyzing the 8 articles included in the present review it was concluded that sleep deprivation negatively influenced physical and sports performance in 5 of the analyzed articles. In addition, it was found that the sleep deprivation period is determinant for athletes' performance in sports tasks.