THE ACUTE EFFECTS OF LOW-LEVEL LASER THERAPY IN VOLLEYBALL PLAYERS BICEPS FATIGUE

Froio J.L.¹, Renno A.C.M.², Chagas E.F.B.³, Campos F.G.L.¹, Kishi M.S.⁴, Pedroni C.R.⁵

¹Sao Paulo State University (UNESP), Marilia, Brazil, ²Federal University of São Paulo - UNIFESP, Santos, Brazil, ³Marilia University (UNIMAR), Marilia, Brazil, ⁴Federal University of Uberlandia - UFU, Uberlandia, Brazil, ⁵Sao Paulo State University, Physical Therapy Department, Marilia, Brazil

Background: Many studies have tried to develop techniques to prevent or reduce the effects of fatigue, especially in athletes. The low-level laser therapy has emerged as an instrument to interact in biological tissues, producing different effects to improved muscle performance.

Purpose: This study aimed to verify the acute effect of therapeutic low-level laser on induced fatigue in biceps braquialis volleyball athletes.

Methods: Double-blind randomized study, 19 male and female volleyball athletes participated in this study. Electromyographic data from biceps muscle in isometric contraction before and after the application of laser. A halter with 75% of peak force obtained by a load cell was used for the fatigue test. Then the volunteers were submitted to laser (active or placebo) in six points of the biceps muscle. The EMG data were analyzed in the frequency by Myosystem® software. The normality of distribution (Shapiro-Wilk test) and repeated measures ANOVA was used to test the interaction between time and group; and t test in order to analyze the behavior within each group between pre and post-fatigue protocol.

Results: None of the variables analyzed had a significant interaction between group and time indicating that the irradiated group showed no advantages over the placebo group.

Conclusion(s): After the proposed fatigue protocol, a single low-level laser application was not enough to produce positive effects on strength performance and electromyographic signal of the biceps braquialis muscle in volleyball players.

Implications: We believe that a chronic effect should be better to LLLT and this could be an helpfull technology for the fatigue condition. Further studies are needed to verify the LLLT efficacy in athetes.

Funding acknowledgements: Thank you to Pró-Reitoria de Extensão Universitária (Proex) - UNESP

Topic: Sport & sports injuries

Ethics approval: This study was approved by the Ethics Committee on Research of Sao Paulo State University, Brazil, protocol number 2014/1061

All authors, affiliations and abstracts have been published as submitted.