Introduction: Laser radiation has positive effects on muscle tissue in terms of skeletal muscle regeneration; it activates skeletal muscle satellite cells, enhances their proliferation and inhibits differentiation, increases muscle metabolism, reduces post exercise blood lactate levels, increases cross-section of muscle fibres and mitochondrial density. Some results of studies indicate that a low-intensity laser reduces muscle damages and slows down muscle fatigue. Purpose: The purpose of the thesis was to present the effects of radiation with low intensity laser on muscle performance of the lower limb, on the basis of a review of professional and scientific literature. Methods: Literature was obtained using following databases: PubMed, PEDro and Springer Link. The review included researches in English language from the last 10 years. Results: The literature review included 8 randomized control studies. Six studies have identified the effect of low intensity laser therapy in combination with endurance exercise and two studies in combination with strength training. The results of the included studies have shown that there has been an improvement in muscle performance in all groups, regardless of the parameters of laser therapy and the variety of exercise. Discussion and conclusion: In seven researches there has been confirmed statistically important muscle improvement, which was noticeable in repetition maximum and maximum voluntary isometric contraction. Due to low number of researches and variety of optimal parameters we cannot conclude with certainty if low intensity laser therapy improves muscle performance. In the future more quality control researches should be done in order to confirm the effects of low-intensity laser therapy.