Objective. To reveal the mechanisms of fatigue and adaptation in sport.
Methods. Analysis of scientific and methodological literature and advanced sports practice.
Results. Fatigue is considered as a special physiological state of an athlete's body, characterized by a temporary decrease in work capacity. It is shown that fatigue is useful and necessary in the process of improving the work capacity of the athlete, which leads to improved athletic performance. The types of fatigue are distinguished depending on the involvement of muscle mass (local, regional, global) and their role in formation of a certain type of adaptation is emphasized. Consideration is given to the relationship: types of muscular work - fatigue - recovery. The chronology of muscular work adaptation process - fatigue, functional and structural changes - is revealed. Multiple repetition of the cycle "work - fatigue" leads to functional and then structural changes in the organs and systems that are directly involved in the performance of specific work. The degree of fatigue, as well as the speed of recovery, is the result of the interaction of many factors, such as volume, intensity, orientation of training load, age, fitness level, degree of sports technique mastery, stage of sports preparation. There are four phases of work and fatigue, which demonstrate the overall dynamics of the processes occurring in the body of the athlete, as well as objective signs of fatigue.
Conclusion. In the course of long-term training process it is important to effectively manage the ratio of fatigue and recovery processes, which is the basic regularity of adaptation changes in the athlete's body in the multifactorial structure of sports training.