Effect of different seasonal strength training protocols on circulating androgen levels and performance parameters in professional soccer players.

OBJECTIVE To examine the effects of three seasonal training programs, largely different in strength volume, on androgen levels and performance parameters in soccer players. DESIGN Sixty-seven soccer players, members of three different professional teams, participated in the study. Strength intensity of the training programs were assessed as high (for Team-A, n=23), moderate (for Team-B, n=22), and low (for Team-C, n=22). Blood samples were analyzed for total-testosterone, free-testosterone, and the metabolic product of activate testosterone 3a-androstendiol glucuronade (3a-Diol-G). Players were tested for maximal oxygen consumption (VO2max), squad-jump (SJ), countermovement-jump (CMJ), 10 m and 20 m sprint performance prior at the beginning of the pre-season period, at the middle (mid-point), and at the end of the competition period (end-point). RESULTS All performance parameters increased significantly until mid-point in all teams (p<0.001). However, performance was further increased only in Team-A only for jumping and sprinting ability between end-point vs mid-point (p<0.001). An effect of the training program of Team-A on TT levels was evident exhibiting significant differences between at all point-measurements (baseline/mid-point:p=0.024, baseline/end-point:p<0.001, mid/end-point:p=0.008), while a marginally significant effect (p=0.051) was detected within Team-B and a non-significant effect in Team-C. Similar results were obtained for 3a-Diol-G in Team-A (p=0.001) where significant differences were found between end-point to both baseline (p=0.001) and mid-point (p=0.038). No differences were detectable for FT. A borderline significant negative correlation was observed between 3a-Diol-G and VO2max in Team-B at mid-point. No other correlations were evident between performance and hormonal parameters. CONCLUSION Our findings suggest that the volume of strength training combined with intensive soccer training caused an elevation of circulating TT and 3a-Diol-G levels in parallel to the induction of performance capacity. It is our opinion that the elevation of endogenous androgens as a result of the volume of strength training indicates that the only method to improve athletic performance is hard training. There are no substitutes or shortcuts. If the organism needs more androgens it will produce them endogenously.