We studied the features of adaptive reactions of human body under conditions of power loads of different volume and intensity. It was found that an increase in the testosteron concentration in blood plasma of untrained young men to 23,2% (Р<0,05) after exercise, compared with the state of rest takes place in response to the high power loads intensity. At the same time, medium intensity work with large amount of workload reduced the concentration of these hormones by 14,3% (Р<0,05). During long-time training an increase in maximum parameters of muscle force (by 32.5% in control and 53,1% in test group) was observed. Thus, adaptive changes in the process of sustained power fitness are characterized by a slowdown of muscle strength and body size in both groups compared with baseline values, which were established after the first month of training. At the same time it was found that the hormonal response to acute power load becomes more pronounced with each subsequent month of classes in fitness force only under the conditions of use during the training sessions of high-intensity physical exercise for a small amount of work.