SERUM HORMONES IN MALE STRENGTH ATHLETES DURING INTENSIVE SHORT-TERM STRENGTH TRAINING

Training-induced adaptations in the endocrine system and strength development were investigated in nine male strength athletes during two separate 3-week intensive strength training periods. The overall amount of training in the periods was maintained at the same level. In both cases the training in the first 2 weeks was very intensive: this was followed by a 3rd week when the overall amount of training was greatly decreased. The two training periods differed only in that training period I included one daily session, while during the first 2 weeks of period II the same amount of training was divided between two daily sessions. In general, only slight and statistically insignificant changes occurred during training period I in mean concentrations of serum hormones examined or sex hormone-binding globulin as well as in maximal isometric leg extensor force. However, during training period II after 2 weeks of intensive strength training a significant decrease (P < 0.05) was observed in serum free testosterone concentration [from 98.4 (SD 24.5) to 83.8 (SD 14.7) pmol.l-1] during the subsequent week of reduced training. No change in the concentration of total testosterone was observed. This training phase was also accompanied by significant increases (P < 0.05) in serum luteinizing hormone (LH) and cortisol concentrations. After 2 successive days of rest serum free testosterone and LH returned to (P < 0.05) their basal concentrations. Training period II led also to a significant increase (P < 0.05) [from 3942 (SD 767) to 4151 (SD 926) N] in maximal force. These findings suggest that in male strength athletes dividing the amount of training into smaller units may create more effective training stimuli leading to further strength development.