ABSTRACT Introduction: In training, fatigue and recovery are antagonistic factors. Physical rehabilitation of athletes and elimination of sports fatigue have gradually become essential factors in improving competitiveness. Muscle relaxation exercises can reduce badminton players' physical effort, allowing them to recover quickly. Objective: Analyze muscle relaxation's effect on fatigue relief until the normalization of physical strength in badminton players. Methods: Twelve badminton players were grouped in cross-sectional tests. During the three weeks of physical training, players performed two training methods: muscle relaxation and complete rest. Laboratory analysis encompassed blood biomarkers such as urea and creatine kinase. Data were collected before and after the interventions, confronted, and studied mathematically and statistically. Results: The proportions of leukocytes and lymphocytes in the muscle relaxation group after resistance exercise were lower than before. The decrease of morning leukocytes in the muscle relaxation group on the second day was less than in the resting group. The recovery effect of the lymphocyte ratio was also better. After special strength training, the value of creatine kinase was significantly higher than before exercise in both the muscle relaxation group and the complete rest group. Conclusion: Muscle relaxation can reduce exercise fatigue in badminton players. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.