Effects of photobiomodulation applied at different times on functional performance and ergogenic response of rugby athletes: Randomized clinical trial.

BACKGROUND: Photobiomodulation (PBM) is indicated to accelerate the recovery of athletes and reduce muscle damage caused by physical exercise. The objective of this study was to establish the best time to apply photobiomodulation to increase the functional performance and ergogenic response of rugby athletes. METHODS: Randomized crossover clinical trial with 18 rugby athletes of both sexes. The interventions were carried out from January to May 2019. The blood levels of creatine kinase (CK) and lactate, and performance in the Modified Star Excursion Balance Test, Single Hop Test, Triple Hop Test, Bangsbo Sprint test (BST), and Yo-Yo intermittent recovery level 1 (YoyoIR1) were evaluated. The athletes underwent two blocks of exercises with the BST and Yoyo-IR1, as well as the random application of four interventions: without application of photobiomodulation (CO), pre-exercise photobiomodulation (PBpre), PBM during the exercise interval (PBint), or post-exercise photobiomodulation (PBpos). The photobiomodulation using light-emitting diodes (850 nm, 8 J/cm2) lasted 10 min and was applied to the quadriceps, hamstrings, and triceps surae muscles. The results were compared between groups and times, and the effect size for the interventions was established. RESULTS: No differences were found between groups in CK, lactate, and performance in the functional tests between groups and times. Only the PBpre presented improved performance in the first Yoyo-1R1 test (p < 0.01), while the PBint improved in the second Yoyo-IR1 test and BST (p < 0.05). CONCLUSION: The PBM did not change muscle damage markers or performance in the functional tests. For an ergogenic response, photobiomodulation applied before exercise improves performance, which can be maintained when PBM is performed in the exercise interval.

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

Effects of audiovisual stimuli on psychological and psychophysiological responses during exercise in adults with obesity.

The present experiment sought to further understanding of the effects of personalised audiovisual stimuli on psychological and psychophysiological responses during exercise in adults with obesity. Twenty-four participants (Mage = 28.3, SD = 5.5 years; MBMI = 32.2, SD = 2.4) engaged in self-paced exercises on a recumbent cycle ergometer and three conditions (sensory stimulation [ST], sensory deprivation [DE], and control [CO]) were administered. Perceptual (attentional focus and perceived exertion), affective (affective state and perceived activation), and psychophysiological (heart rate variability) parameters were monitored throughout the exercise bouts. A one-way repeated measures analysis of variance was used to compare self-reported and psychophysiological variables (main and interaction effects [5 Timepoints × 3 Conditions]). The results indicate that ST increased the use of dissociative thoughts throughout the exercise session (ηp2 = .19), ameliorated fatigue-related symptoms (ηp2 = .15) and elicited more positive affective responses (ηp2 = .12) than CO and DE. Accordingly, personally-compiled videos are highly effective in ameliorating exertional responses and enhancing affective valence during self-paced exercise in adults with obesity. Audiovisual stimuli could be used during the most critical periods of the exercise regimen (e.g., first training sessions) when individuals with obesity are more likely to focus on fatigue-related sensations.

Cold water immersion or LED therapy after training sessions: effects on exercise-induced muscle damage and performance in rats.

Cryotherapy and phototherapy have been suggested as recovery methods due to their anti-inflammatory effects. They may also induce mitochondrial biogenesis, thus favoring endurance training adaptation. The aim of this study was to evaluate the anti-inflammatory and ergogenic effects of phototherapy or cold water immersion (CWI) applied daily after exercise in rats. Thirty-five rats were divided into five groups: control (CO), non-exercised (CE), passive recovery (PR), cold water immersion (CWI), and LED therapy (LED). The CO and CE groups were not submitted to training; however, the CE were submitted to an exhaustion test after the training period. Low-intensity swimming training (21 sessions, 45 min) was performed followed by passive recovery (PR), CWI (10 °C, 5 min), or infrared irradiation (940 nm, 4 J/cm2). Forty-eight hours after the final training session, the CE, PR, CWI, and LED animals were submitted to an exhaustion test. The animals were euthanized 24 h later and submitted to hematological, creatine kinase (CK), and C-reactive protein (PCR) analysis. Gastrocnemius and soleus muscles were submitted to histological analysis. No differences in blood cell counts, CK, and PCR were detected between groups. The CE group presented an increased number of areas with necrosis in the gastrocnemius and soleus muscles. The PR group presented the highest frequency of areas with edema and inflammation followed by CWI and LED groups. None of the recovery methods improved the performance in the exhaustion test. Successive applications of recovery methods do not improve exercise performance, but downmodulate the inflammation and prevent muscle necrosis.

Psychophysiological effects of audiovisual stimuli during cycle exercise.

Immersive environments induced by audiovisual stimuli are hypothesised to facilitate the control of movements and ameliorate fatigue-related symptoms during exercise. The objective of the present study was to investigate the effects of pleasant and unpleasant audiovisual stimuli on perceptual and psychophysiological responses during moderate-intensity exercises performed on an electromagnetically braked cycle ergometer. Twenty young adults were administered three experimental conditions in a randomised and counterbalanced order: unpleasant stimulus (US; e.g. images depicting laboured breathing); pleasant stimulus (PS; e.g. images depicting pleasant emotions); and neutral stimulus (NS; e.g. neutral facial expressions). The exercise had 10 min of duration (2 min of warm-up + 6 min of exercise + 2 min of warm-down). During all conditions, the rate of perceived exertion and heart rate variability were monitored to further understanding of the moderating influence of audiovisual stimuli on perceptual and psychophysiological responses, respectively. The results of the present study indicate that PS ameliorated fatigue-related symptoms and reduced the physiological stress imposed by the exercise bout. Conversely, US increased the global activity of the autonomic nervous system and increased exertional responses to a greater degree when compared to PS. Accordingly, audiovisual stimuli appear to induce a psychophysiological response in which individuals visualise themselves within the story presented in the video. In such instances, individuals appear to copy the behaviour observed in the videos as if the situation was real. This mirroring mechanism has the potential to up-/down-regulate the cardiac work as if in fact the exercise intensities were different in each condition.