Preconditioning Effects of Photobiomodulation on Repeated-Sprint Ability of Professional Basketball Players.

ABSTRACT: Giovanini, B, Altimari, LR, de Paula Ramos, S, Alves Okazaki, VH, Okuno, NM, and Junior, AF. Preconditioning effects of photobiomodulation on repeated-sprint ability of professional basketball players. J Strength Cond Res 37(1): 224-229, 2023-The purpose of this study was to investigate the preconditioning effects of photobiomodulation on repeated-sprint ability of professional basketball players. Ten professional basketball players took part in this randomized, double-blind, placebo-controlled, crossover study. The subjects attended 2 repeated-sprint test sessions. In each session, the subjects performed a general warm-up, followed by a familiarization sprint. Afterward, the subjects received either the photobiomodulation (660 and 850 nm, 12 J·cm-2, 83.4 J per point, 10 points, light-emitting diode [LED] treatment) or placebo intervention and performed the repeated-sprint test. The repeated-sprint test consisted of ten 30-m sprints with 1 change of direction (15 + 15 m), interspersed by 30 seconds of passive recovery. Sprint times and heart rate responses were monitored during the test. To compare moments and conditions, linear mixed-effects models were applied with statistical significance set at p < 0.05, and Cohen's d was used as effect size (ES). The LED treatment could not improve total time (p = 0.662; ES = -0.06), best time (p = 0.869; ES = 0.02), fatigue index (p = 0.169; ES = 0.64), or sprint decrement (p = 0.124; ES = -0.75) when compared with the placebo condition. In addition, mean heart rate (p = 0.687; ES = 0.07) and maximal heart rate (p = 0.837; ES = -0.03) were similar between conditions. We concluded that the LED condition could not improve the repeated-sprint ability of professional basketball players.

How Positional Constraints Affect Footedness in Football: A Notational Analysis of Five Leagues in Europe.

In elite-level soccer, the ability to take shots with both limbs from different positions in the pitch may be key to success. This research aimed to: 1) analyze footedness of elite-football players in European leagues during shooting by computing frequency of right- and left-foot use and accuracy; and 2) investigate whether an athlete's distance from the target (goal, penalty, and outside penalty area) and pitch zone (center, left, or right from the goal) can constrain foot selection during shooting. We analyzed 1826 games from the 2017/18 season, divided between: Spanish LaLiga (380 matches); Italian Serie A (380 matches); English Premier League (380 matches); German Bundesliga (306 matches); and French Ligue 1 (380 matches). Results revealed asymmetrical proportions of foot selection, favoring the preferred foot for right- and left-footed athletes. Frequency of preferred foot selection increased as a function of distance from the target (i.e., the farther the athlete, higher the percentage of preferred foot selection). Shots taken from the left side were more often performed with the right foot and vice-versa, for both left- and right-footed athletes. Interestingly, asymmetries were observed only in foot selection, but not in performance, as success rate did not vary between limbs in any position.

Residual effects of mental fatigue on subjective fatigue, reaction time and cardiac responses / Efectos residuales de la fatiga mental en la fatiga subjetiva, tiempo de reacción y respuestas cardíacas / Efeitos residuais da fadiga mental na fadiga subjetiva, tempo de reação e respostas cardíacas

This study investigated the residual effects of mental fatigue induced by the 30-minute incongruent Stroop Color Word task on subjectively perceived fatigue, reaction time, and heart rate variability (HRV) in 20 adult volunteers (10 men; 10 women). Dependent variables were assessed before, immediately after, and at 15, 30, 45, and 60 minutes after two conditions: (a) a 30-minute incongruent Stroop Color Word task (mental fatigue condition); or (b) a 30-minute control condition. At pre-testing, there were no significant differences between experimental conditions for any variable. However, there was a residual effect of mental fatigue on psychological responses for up to ~15 minutes after the experimental manipulation (p < 0.01). For the reaction time task, significant differences were observed only immediately after the mental fatigue, compared to the control condition (p < 0.0001). There were no significant differences between experimental conditions for any parameters of HRV at any testing period. In addition, there were no significant gender related differences at any period or in either condition for any variable. The data suggest that mental fatigue can alter psychological responses for up to ~15 min after its induction, and mental fatigue may impair cognitive reaction time performance without changing autonomic cardiac responses

Este estudio investigó los efectos residuales de la fatiga mental inducidos por 30 minutos Test de Stroop con palabra con color incongruente sobre la fatiga percibida subjetivamente, el tiempo de reacción y la variabilidad de la frecuencia cardíaca (HRV) en 20 voluntarios adultos (10 hombres, 10 mujeres). Las variables dependientes se evaluaron antes, inmediatamente después y a los 15, 30, 45 y 60 minutos después de dos condiciones: (a) Test de Stroop con palabra con color incongruente de 30 minutos (condición de fatiga mental); o (b) condición de control de 30 minutos. En la pre condiciones, no hubo diferencias significativas entre las condiciones experimentales para ninguna variable. Sin embargo, hubo un efecto residual de la fatiga mental en las respuestas psicológicas durante hasta ~ 15 minutos después de la manipulación experimental (p < 0,01). Para la tarea de tiempo de reacción, se observaron diferencias significativas solo inmediatamente después de la fatiga mental, en comparación con la condición de control (p < 0,0001). No hubo diferencias significativas entre las condiciones experimentales para ningún parámetro de HRV en ningún período. Además, no hubo diferencias significativas relacionadas con el género en ningún período ni en ninguna de las condiciones para ninguna variable. Los datos sugieren que la fatiga mental puede alterar las respuestas psicológicas hasta ~ 15 min después de su inducción, y la fatiga mental puede afectar el rendimiento del tiempo de reacción cognitiva sin cambiar las respuestas cardíacas autónomas

Este estudo investigou os efeitos residuais da fadiga mental induzida por 30 minutos do teste de Stroop com a palavra de cor incongruente na fadiga percebida de maneira subjetiva, tempo de reação e variabilidade da frequência cardíaca (VFC) em 20 voluntários adultos (10 homens; 10 mulheres). As variáveis dependentes foram avaliadas antes, imediatamente após e aos 15, 30, 45 e 60 minutos após duas condições: (a) teste de Stroop com a palavra de cor incongruente de 30 minutos (condição fadiga mental); ou (b) uma condição controle de 30 minutos. No pré-teste, não houve diferenças significativas entre as condições experimentais para qualquer variável. No entanto, houve um efeito residual da fadiga mental nas respostas psicológicas por até ~ 15 minutos após a manipulação experimental (p <0,01). Para o teste de tempo de reação, foram observadas diferenças significativas apenas imediatamente após a fadiga mental, em comparação com a condição controle (p <0,0001). Não houve diferenças significativas entre as condições experimentais para quaisquer parâmetros da VFC em qualquer período. Além disso, não houve diferenças significativas relacionadas ao gênero em qualquer período ou em qualquer condição para qualquer variável. Os dados sugerem que a fadiga mental pode alterar as respostas psicológicas por até 15 minutos após sua indução, e a fadiga mental pode prejudicar o desempenho cognitivo pela piora tempo de reação sem alterar as respostas autonômicas cardíacas