Effects of low level laser therapy in the electromyography activy of biceps brachii muscle in young males during a resistive training program

Abstract

Among many changes associated with training that lead to the decline of muscle function can be cited the muscle fatigue. Moreover, muscle performance during a physical training can be reduced by early muscle fatigue. The laser, by its biomodulation effects, may be a resource for reducing muscle fatigue and increasing the effectiveness of training. The objective of this study is to analyze the influence of low level laser therapy (LLLT) in the biceps brachii performance of young males before and after a strength training program and in the load values used in this training. For this, 45 young male will be randomly divided into 3 groups: strength training (n = 15) associated with sham laser irradiation, group strength training associated with the active laser irradiation (n = 15) and control group (n = 15) did not submitted to training and laser therapy. The analysis of peripheral muscle fatigue will be performed by surface electromyography. Biceps brachii strength training will last eight weeks and it will be performed in a Scott Bench following the recommendations of the American College of Sports Medicine. The LLLT will be held immediately after each training session over biceps brachii muscle of the dominant arm. Before first, after last training session and 24 hours after, electromyographic activity will be made after biceps brachii fatigue protocol. The fatigue protocol consists of performing a isometric submaximal contraction, performed until muscle exhaustion, with 80% of total force obtained during a muscular isometric contraction. Eletromyographic raw signal will be used to derive the median frequency (FMed), mathematical calculation used to analyze electromyographic fatigue. Normalized FMed will be compared inter and intra-groups, as well as progression of load values during training will be compared between groups. The normality in terms of sample distribution will be investigated for choosing appropriate statistical tests.