INFLUENCE OF TRAINING ON THE RESPONSE TO EXERCISE OF ADRENOCORTICOTROPIN AND GROWTH-HORMONE PLASMA-CONCENTRATIONS IN HUMAN SWIMMERS

The aim of the present study was to evaluate the response of adrenocor ticotropin ([ACTH]) and growth hormone ([GH]) concentrations to a typi cal aerobic swimming set during a training season. Nine top-level male endurance swimmers (age range 17-23 years) were tested during three t raining sessions occur; ring 6, 12 and IS weeks after the beginning of the season. During each session, after a standard warm-up, the swimme rs performed a training set of 15 x 200-m freestyle, with 20 s of rest between repetitions, at a predetermined individual speed. Blood sampl es were collected before warm-up and at the end of the training set. A few days before each session, the individual swimming velocity corres ponding to the 4 mmol . l(-1) blood lactate concentration (nu(4)) was assessed as a standard of aerobic performance. Aerobic training affect ed nu(4) levels, which were highest 18 weeks after the beginning of th e season; at the same time, while [ACTH] response was attenuated,[GH] response was enhanced. These results could be considered as adaptation s to the exercise intensity. In our training programme, these adaptati ons seemed to have occurred between the 12th and 18th weeks of the tra ining season.