PERFORMANCE AND HORMONAL RESPONSES OF COMPETITIVE SWIMMERS TO HIGH-INTENSITY INTERVAL TRAINING AND REGENERATION

Abstract

PURPOSE The purpose of this study was to compare the effects of 3 weeks of HIT versus E training, and 1 week of regeneration (R), on swimming performance and circulating hormone status. METHODS Twenty, (8 female and 12 male) competitive swimmers were pair matched according to gender and prior competitive swimming results and then randomly assigned to either the E or HIT group. Swimming performance was assessed via 400-m and 5x100-m water tests at baseline (B), after training weeks 1 and 3 (Twk1, Twk3), and R. Resting venous blood samples were obtained at B, after Twk3 and R for the evaluation of C-reactive protein (CRP), creatine kinase (CK), hematocrit (Hct), Hemoglobin (Hb), serum testosterone (T), cortisol (C), human growth hormone (hGH), prolactin (PRL), and progesterone (P). RESULTS The HIT group had significantly higher training blood lactates compared to the E group (HIT=7.3 ± 2.0 vs E=2.7 ± 1.5 Mmol). There were significant improvements in 100-m swimming performance and maximal blood lactate in both E and HIT groups after T3 and R. Blood Lactate after 400-m freestyle swimming also significantly increased in both groups at Twk1 and decreased after R. Serum hGH, was unchanged during the study. Resting serum C, PRL, and P were significantly increased in both training groups after Twk3 and remained elevated after R. Both E and HIT group serum T was significantly elevated after R. and T/C ratio was decreased after Twk3. CONCLUSIONS These results suggest that 3 wks of either HIT or E training can improve swimming performance with a trend for greater improvement with HIT. The hormonal data suggest that training stress, demonstrated by resting hypothalmo-anterior pituitary activity, was increased following training, and 1 week of regeneration was not adequate to relieve this training stress. This study was funded in part by grants from Saarland-Sporttot GmbH.