The effects of training on hormonal concentrations and physical performance of football referees

As no study has explored the impact of physical stress on hypothalamic-pituitary-gonadal axis hormones over a long period, the purpose of this study was to determine the effects of the football season period on plasma cortisol and testosterone concentrations and referee's physical performances. Physical tests and plasma cortisol and testosterone concentrations were assayed before the beginning of the training period, just after the training period, at the middle of the season, and at the end of the season, in 29 male football referees and 30 healthy control subjects. Results showed significant differences in hormone concentrations at the four-time points evaluated. Plasma cortisol increased during the first training period from 15.8 ± 3.8 to 21.7 ± 5.1 µg/dl (p < 0.001), then decreased during the season and at the end of it was 18.7 ± 2.4 µg/dl. Before the beginning of the training period, plasma testosterone concentration was 386.1 ± 58.8 ng/dl; after the training period, it increased to 572.2 ± 88.1 ng/dl (p < 0.001) and then returned to baseline levels at the end of the season. Between the start of the training period and the end of the season, significant differences were observed in physical performances of referees. Plasma cortisol and testosterone levels significantly (p < 0.0001 for both) correlated with Yo-Yo intermittent recovery test level 1 (YYIRT1) and maximal oxygen consumption (VO2max) at the end of the training period. In the middle season, plasma testosterone concentration only significantly (p < 0.0001) correlated with YYIRT1 and VO2max. These data underline the importance of set up training protocols that present the prospective to favor positive physiological adaptations.