Effects of Low Laser Irradiation on Peak Power Muscle Performance and Recovery

Background: Low level laser therapy (LLLT) was shown to improve tissue repair and regeneration, increase angiogenesis, reduce pain and inflammation, and stimulate the formation of new muscle fibers. The mechanism by which LLLT exerts its effect include activation of mitochondrial enzymes results in an increased intracellular energy. The effects of LLLT on skeletal muscles was evaluated in humans and found to improve graded exercise test performance, decreased exercise induced pain, improved muscle performance and recovery after acute exercise.

Aims of study: To evaluate the influence of LLLT, using B-Cure laser on: 1) maximal performance, and 2) recovery after fatigued exercise.

Methods: Sixty healthy physical education students, aged 20-35, were recruited to this double-blind cross over study. The study included two experiments. Each 30 participants performed two interventions with real or sham treatment: 1) measured muscle peak power and peak torque in 5 repetitions in knee flexion and 2) measured muscle recovery after the induction of fatigue by evaluating peak power and peak torque in 5 repetitions of knee flexion.

Results: There were no differences between the conditions (real or sham treatment) regarding the total work (F(1,28)=1.09, p=.31), or peak torque (F(1,29)=.056, p=.814). Also, there was no effect of LLLT on muscle recovery as measured by total work (F(1,27)=.16, p=.69) and peak torque (F(1,29)=.056, p=.814).

Conclusions: LLLT applied for 10 min did not improve muscle function or muscle recovery after fatigue.