The purpose of the study was to analyze the dynamics of the component composition of the body of athletes-bodybuilders at the stage of specialized basic training. Materials and methods. The study included 60 athletes aged from 18 to 19 years old. Three research groups were formed, 20 athletes in each group. These groups of athletes, divided by the method of usual sampling and age, qualification and anthropometric characteristics, did not differ significantly. The only difference was in the proposed training programs. Such methods were used: theoretical analysis of scientific and methodological literature and method of bioimpedancemetry. This is a non-invasive, biophysical method, which is based on measuring the electrical resistance of biological tissues of the body and computer processing of the results, which allow to determine the composition of the body, compliance with its values and assess the effectiveness of the athlete's adaptation to training loads quickly and accurately. This method allows to determine the following indicators of body composition: fat content (total mass of fat cells in the body); and content of lean mass (the proportion of body weight that contains everything that is not adipose tissue: muscles, internal organs, bones, nerve cells, all fluids in the body). Results and discussion. Due to the results of the component composition of body weight of athletes using the method of bioimpedancemetry, it was found that the most significant increase in non-fat body weight (8.2%, p <0.05), compared with baseline, was recorded in athletes of the second main group. And the lowest growth rates of the control indicator for the period of the whole pedagogical research (by 3.9%, p <0.05) were obtained from the athletes of the control group. A comparative analysis of the dynamics of body fat gain of bodybuilders throughout the study period shows a significant decrease in the controlled indicator (9.2%, p <0.05), compared with baseline data from the second main group. At the same time, the smallest decreases in body fat (by 2.8%, p <0.05) were recorded in athletes of the first main group. Conclusion. Thus, the results show that the use of the generally accepted basic training program for athletes in the generally accepted program of training in bodybuilding is less effective than our proposed program (especially through the use of the method of "premature fatigue")