The sex differences in the 10,000 m race strategy

Abstract Aim: This study aimed to compare the running strategy between men and women in the 10,000 m race. Methods: Data from one-hundred and twenty-nine athletes who competed the 10,000 m final of the 2015, 2017 and 2019 world championship were grouped according to gender: 1) male group (n= 63; age= 25.9±4.4), and 2) female group (n= 66; age= 27.3±4.8). The running strategy was determined by assessing velocity over each kilometer. The velocity was calculated from the times available on the official website of the International Athletics Federation. Results: Men decreased running velocity after the first kilometer and kept the speed stable until km 9 and the kilometer 10 was greater when compared with 6-9 kilometer, while women increase running velocity until km 2 and kept the speed stable until km 9. The kilometer 10 velocity was greater when compared with 1-9 kilometer. (p< 0.001). In addition, women showed a greater average velocity variation when compared to men (p< 0.001). Conclusion: Our findings show a sex differences in the 10,000 m race strategy between world-class.

Effect of a school soccer competition with consecutive day games on the recovery status of U-19 players / Efeito de uma competição escolar de futebol com jogos em dias consecutivos no estado de recuperação de jogadores sub-19

Abstract The present study aimed to evaluate the effect of a school soccer competition with consecutive day games on the recovery status of U-19 players. Thirty-one school athletes (17.1±1.1 years) who played a U-19 school soccer competition (composed of two groups of four soccer teams each, followed by semifinals and final) were randomly evaluated. Games lasted 70 min (two periods of 35 min with 15 min rest interval), and they were played on consecutive days with 24 h between each game. Delayed onset muscle soreness (DOMS) and Total Quality Recovery (TQR) were measured before group phase games (n= 31) and semifinals games (n= 18). The internal game load was measured by the session rate of perceived exertion (session-RPE) method. TQR was higher before the first game when compared to the other games (p< 0.001). DOMS increased after the first game and did not return to baseline before the fourth game. Both session-RPE and internal load of the fourth game were higher than in the other games (p< 0.001). In addition, there was no correlation between internal game load and TQR (p> 0.05). The monotony observed during the evaluated period was 3.1±2.0 AU. The results indicate that the 24 h rest period seems to be insufficient for complete recovery of U-19 soccer school athletes, suggesting the organization of U-19 school soccer competitions with higher rest interval between games and search for methods to increase the recovery rate.

Resumo O presente estudo objetivou analisar o efeito de uma competição escolar de futebol com jogos em dias consecutivos no estado de recuperação física de jogadores sub-19. Foram avaliados, de forma aleatória, 31 atletas escolares (17,1±1,1 anos) participantes de uma competição escolar de futebol de campo sub-19, composta de duas chaves com quatro equipes cada, seguido de semifinais e final. Os jogos tiveram 70 min de duração (dois tempos de 35 min com 15 min de intervalo), e foram realizados em dias consecutivos com intervalo de 24h entre cada jogo. Foi medida a dor muscular de início tardio (DOMS) e Qualidade Total de Recuperação (QTR) antes de cada jogo da primeira fase (n= 31) e da semifinal (n=18). A carga interna dos jogos foi medida a pelo método da percepção subjetiva do esforço da sessão (PSE-sessão). A QTR foi maior antes do primeiro jogo em comparação com os demais jogos (p< 0.001). A DOMS aumentou após o primeiro jogo e não retornou aos valores basais antes do quarto jogo (p< 0.001). A PSE-sessão e a carga interna do quarto jogo foram maiores que as dos demais jogos (p< 0,001). Em adição, não houve correlação entre a carga interna do jogo e a QTR (p> 0,05). A monotonia encontrada no período avaliado foi de 3,1±2.0 UA. Os resultados indicam que o período de 24h parece ser insuficiente para a completa recuperação de atletas escolares de futebol sub-19, sugerindo a organização de competições escolares de futebol sub-19 com maior intervalo entre os jogos e busca por métodos que acelerem a recuperação.

Ultrasound imaging in women's arm flexor muscles: intra-rater reliability of muscle thickness and echo intensity

ABSTRACT Background Different ultrasound parameters have been frequently used to assess changes associated with training, aging, immobilization, and neuromuscular diseases. However, an exploratory reliability analysis of the echo intensity (EI) and muscle thickness (MT) of the forearm flexors is scarce, especially in women. Objective The purpose of the present study was to determine the intra-rater reliability of MT and EI assessed by ultrasound in young women. Method Ultrasonographic MT and EI were acquired in the forearm flexors of 41 young women (22±2 yrs). Reliability was calculated using intraclass correlation coefficient (ICC2,1), standard error of measurement (SEM), coefficient of variation (CV), smallest detectable change (SDC), and Bland and Altman plot analysis. Results ICC values for MT and EI were 0.88 (95% CI: 0.78-0.93). The SEM and CV values were lower than 10%. Bland and Altman analysis revealed that ultrasound mean differences were 0.27 mm (Limits of Agreement - LOA 95%: - 2.6 to 3.2 mm) and -0.09 a.u. (LOA 95%: - 10.9 to 10.7 a.u.). Conclusion MT and EI assessed by ultrasonography in young women appear to be reliable and may be used to monitor changes in muscle mass induced by strength training when these changes exceed the precision of ultrasound.