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.

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.

Post-exercise cold water immersion does not alter high intensity interval training-induced exercise performance and Hsp72 responses, but enhances mitochondrial markers

This study aims to evaluate the effect of regular post-exercise cold water immersion (CWI) on intramuscular markers of cellular stress response and signaling molecules related to mitochondria biogenesis and exercise performance after 4 weeks of high intensity interval training (HIIT). Seventeen healthy subjects were allocated into two groups: control (CON, n = 9) or CWI (n = 8). Each HIIT session consisted of 8-12 cycling exercise stimuli (90-110 % of peak power) for 60 s followed by 75 s of active recovery three times per week, for 4 weeks (12 HIIT sessions). After each HIIT session, the CWI had their lower limbs immersed in cold water (10 °C) for 15 min and the CON recovered at room temperature. Exercise performance was evaluated before and after HIIT by a 15-km cycling time trial. Vastus lateralis biopsies were obtained pre and 72 h post training. Samples were analyzed for heat shock protein 72 kDa (Hsp72), adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) assessed by western blot. In addition, the mRNA expression of heat shock factor-1 (HSF-1), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 and 2 (NRF1 and 2), mitochondrial transcription factor A (Tfam), calcium calmodulin-dependent protein kinase 2 (CaMK2) and enzymes citrate synthase (CS), carnitine palmitoyltransferase I (CPT1), and pyruvate dehydrogenase kinase (PDK4) were assessed by real-time PCR. Time to complete the 15-km cycling time trial was reduced with training (p < 0.001), but was not different between groups (p = 0.33). The Hsp72 (p = 0.01), p38 MAPK, and AMPK (p = 0.04) contents increased with training, but were not different between groups (p > 0.05). No differences were observed with training or condition for mRNA expression of PGC-1α (p = 0.31), CPT1 (p = 0.14), CS (p = 0.44), and NRF-2 (p = 0.82). However, HFS-1 (p = 0.007), PDK4 (p = 0.03), and Tfam (p = 0.03) mRNA were higher in CWI. NRF-1 decrease in both groups after training (p = 0.006). CaMK2 decreased with HIIT (p = 0.003) but it was not affected by CWI (p = 0.99). Cold water immersion does not alter HIIT-induced Hsp72, AMPK, p38 MAPK, and exercise performance but was able to increase some markers of cellular stress response and signaling molecules related to mitochondria biogenesis.

Effect of cryotherapy on the ankle temperature in athletes: ice pack and cold water immersion

Introduction Cryotherapy is often used for rehabilitation of injured athletes. Objective To compare the effectiveness of ice pack (IP) and cold water immersion (CWI) on lowering the ankle skin surface temperature in athletes. Materials and methods Thirteen athletes (seven women and six men), age 19.53 (± 2.9) years. IP and CWI were applied on the anterior talofibular ligament (ATFL) of the dominant leg for 30 minutes. The skin surface temperature was measured with an infrared digital thermometer prior to the application and during cryotherapy (10, 15, 20, 25 and 30 minutes) and up to two hours of rewarming. During rewarming, the athletes remained at rest and the temperature was measured every 1 minute until 10 minutes, every 5 minutes for up to an hour and every 15 minutes until 2 hours. Results The two types of cold application were effective in lowering the skin surface temperature after the 30-minute procedure. Significant differences were observed among the following temperatures: pre-application (IP = 29.8 ± 2.4 °C and CWI = 27.5 ± 3 °C – P < 0.05); after 30 minutes (IP = 5 ± 2.4 °C and CWI = 7.8 ± 3 °C – P < 0.01). For rewarming, after 25 minutes (IP = 20.8 ± 3.3 °C and CWI = 18.2 ± 2.7 °C – P < 0.04); after 45 minutes (IP = 24.5 ± 2.3 °C and IP = 22.1 ± 3.5 °C – P < 0.05); after 75 minutes (IP = 26.4 ± 2.2 °C and CWI = 24 ± 2.7 °C – P < 0.02). Conclusion After the 30-minute application, both IP and CWI produced the appropriate temperature; however the application of CWI produced the lowest temperature during rewarming.

Análise comparativa do equilíbrio unipodal de atletas de ginástica rítmica

INTRODUÇÃO: A ginástica rítmica (GR) requer alto nível de qualidade física; assim, o bom desempenho é dependente da força e resistência muscular, coordenação motora e equilíbrio postural. OBJETIVO: Desenvolver uma análise comparativa do equilíbrio unipodal de atletas de GR. MÉTODOS: Foram avaliadas dez atletas de GR, do sexo feminino, por meio de uma plataforma de força em apoio unipodal e testes funcionais de equilíbrio (Side Hop Test e Figure of Eight Hop Teste). Para a plataforma, os parâmetros do Centro de Pressão (COP) nas direções anteroposterior e mediolateral foram utilizados para análise, enquanto para os testes funcionais, o tempo-segundos de performance. RESULTADOS: Diferença significativa (p = 0,01) foi encontrada entre os membros inferiores no parâmetro de frequência média na direção mediolateral, no qual o membro inferior não dominante apresentou maior estabilidade postural do que o dominante. Para os testes funcionais não houve diferença significativa entre os membros. CONCLUSÃO: A diferença encontrada no controle do equilíbrio na direção mediolateral pode estar relacionada às diferenças nas ações musculares da região do quadril, na qual durante a prática do esporte para estabilização, manutenção do tronco e execução de manobras com os membros inferiores estão presentes. Estes resultados indicam a necessidade de um programa de reequilíbrio e estabilização pélvica para as atletas analisadas no intuito de preservar a simetria muscular dos membros para o bom desempenho esportivo.