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.

Effects of light emitting diode (LED) therapy at 940 nm on inflammatory root resorption in rats.

The effects of LED therapy at 940 nm on periodontal healing, inflammatory cell infiltration, and root resorption were analyzed in an experimental model of orthodontic tooth movement in rats. Twenty-five male Wistar rats were allocated into four experimental groups: Control animals (Co, n = 5), Controls + LED therapy (CoLED, n = 6), animals submitted to orthodontic force (RR, n = 7) and submitted to orthodontic force + LED therapy (RRLED, n = 7). All procedures were approved by the Committee for Ethics in Animal Experimentation of the Universidade Estadual de Londrina (protocol CEEA 5/2010 37359). A force of 50 g was applied to the right upper molars of RR and RRLED groups. On days 2, 3, and 4 after orthodontic treatment, the CoLED and RRLED groups received LED irradiation (940 nm, 4 J/cm(2)). The animals were killed on day 7 for histological analysis. An increased number of root resorption lacunae was found only in the RR group (p < 0.05). The RR group also presented more osteoclasts (p < 0.005) and inflammatory cell infiltration (p < 0.005) than the control group. The RRLED group presented fewer osteoclasts (p < 0.005) and inflammatory cells (p < 0.005) in the periodontal ligament than the RR group. The CoLED and RRLED groups presented more periodontal fibroblasts (p < 0.005) than non-irradiated groups. RRLED presented more blood vessels (p < 0.01) in the periodontal ligament than the RR group. In conclusion, the results suggest that LED therapy improved periodontal tissue repair and decreased inflammation and root resorption after the application of orthodontic force.

Effects of light emitting diode (LED) therapy and cold water immersion therapy on exercise-induced muscle damage in rats.

The aim of this work is to analyze the effects of LED therapy at 940 nm or cold water immersion therapy (CWI) after an acute bout of exercise on markers of muscle damage and inflammation. Thirty-two male Wistar rats were allocated into four groups: animals kept at rest (control), exercised animals (E), exercised + CWI (CWI), and exercised + LED therapy (LED). The animals swam for 100 min, after which blood samples were collected for lactate analysis. Animals in the E group were returned to their cages without treatment, the CWI group was placed in cold water (10°C) for 10 min and the LED group received LED irradiation on both gastrocnemius muscles (4 J/cm(2) each). After 24 h, the animals were killed and the soleus muscles were submitted to histological analysis. Blood samples were used for hematological and CK analyses. The results demonstrated that the LED group presented fewer areas of muscle damage and inflammatory cell infiltration and lower levels of CK activity than the E group. Fewer areas of damaged muscle fiber were observed in the LED group than in CWI. CWI and LED did not reduce edema areas. Hematological analysis showed no significant effect of either treatment on leukocyte counts. The results suggest that LED therapy is more efficient than CWI in preventing muscle damage and local inflammation after exercise.

Effects of 940 nm light-emitting diode (led) on sciatic nerve regeneration in rats.

The objective of the present study was to evaluate the effect of 940 nm wavelength light emitting diode (LED) phototherapy on nerve regeneration in rats. Forty male Wistar rats weighing approximately 300 g each were divided into four groups: control (C); control submitted to LED phototherapy (CLed); Sciatic Nerve Lesion without LED phototherapy (L); Sciatic Nerve Lesion with LED phototherapy (LLed). The lesion was caused by crushing the right sciatic nerve. A dose of 4 J/cm(2) was used for ten consecutive days beginning on the first postoperative day. Groups C and L were submitted to the same procedure as the LLed group, but the equipment was turned off. The LED phototherapy with 940 nm wavelength reduced the areas of edema, the number of mononuclear cells present in the inflammatory infiltration, and increased functional recovery scores at 7, 14 and 21 days. The results suggest that the use of phototherapy at 940 nm after nerve damage improves morphofunctional recovery and nerve regeneration.

Efeitos biológicos da luz: aplicação de terapia de baixa potência empregando LEDs (Light Emitting Diode) na cicatrização da úlcera venosa: relato de caso / Biological effects of light: application of low power therapy using LEDs (Light Emitting Diode) on the healing of venous ulcers: a case report

O emprego de fontes de luz de baixa potência, como diodos emissores de luz-LEDs, pode propiciar um recurso terapêutico opcional aos convencionais ou ser utilizado em conjunto com estes, com a vantagem do baixo custo e comprovada eficiência no tratamento de úlceras e outras enfermidades. O estudo de caso foi realizado com um paciente do Ambulatório de Clinicas do HC/UEL que apresenta úlceras nos membros inferiores. A aplicação foi feita uma vez por semana, empregando LEDs com comprimento de onda de 628 nm na úlcera do membro inferior esquerdo e o direito foi utilizado como controle. A evolução foi medida por meio de registro fotográfico, medida da área e mensuração da dor. Foram realizadas 18 sessões. Os resultados apontaram mudanças nas características clínicas da lesão e a área cicatrizada foi 30% maior em relação à úlcera controle. Quanto à dor, a escala análoga visual variou de oito para zero no membro irradiado e de nove para dois no controle. Assim, pode-se concluir que a LED terapia é um recurso de eleição no tratamento da úlcera venosa, nos aspectos cicatriciais e redução da dor.

The use of low power light sources, such as diodes emitters of light – LEDs, provides an alternative and complementary therapeutic resource to the conventional ones, with the advantage of being cost-effective and reliable in the treatment of ulcers and other infirmities. This study was carried out on a patient from the HC/UEL Outpatient Clinic with ulcers on both lower limbs. LEDs were applied once a week, using a wave length of 628 nm on the left lower limb ulcer ,using the right limb as control. Evolution was measured through photographic registers, area size and pain assessment. Eighteen sessions were performed. Results showed that changes were observed on the clinical characteristics of the injury and the healed area was 30% larger when compared to the control. As for the pain assessment, the visual analogue scale varied from eight to zero on the limb radiated and from nine to two on the control. Thus, it can be concluded that the LED therapy is a resource of choice for treating venous ulcer, in both healing and pain reduction aspects.