Resumen de Body Composition and Power Performance Improved After Weight Reduction in Male Athletes Without Hampering Hormonal Balance

Heikki T. Huovinen, Juha J. Hulmi, Juha Isolehto, Heikki Kyröläinen, Risto Puurtinen, Tuomo Karila, Krzysztof Mackala, Antti A. Mero

• The aim of this study was to investigate the effects of a 4-week weight reduction period with high protein and reduced carbohydrate intake on body composition, explosive power, speed, serum hormones, and acid-base balance in male track and field jumpers and sprinters. Eight participants were assigned to a high weight reduction group (HWR; energy restriction 750 kcal·d-1) and 7 to a low weight reduction group (LWR; energy restriction 300 kcal·d-1). Energy and carbohydrate intake decreased significantly (p <= 0.05) only in HWR by 740 ± 330 kcal·d-1 and 130 ± 29 g·d-1, respectively. Furthermore, total body mass and fat mass decreased (p <= 0.05) only in HWR by 2.2 ± 1.0 kg and 1.7 ± 1.6 kg, respectively. Fat-free mass (FFM), serum testosterone, cortisol, and sex hormone–binding globulin did not change significantly. Ca2+ ion and pH decreased (p <= 0.05) only in HWR (3.1 ± 2.8% and 0.8 ± 0.8%, respectively), whereas declined (p <= 0.05) in both groups by 19.3 ± 6.2% in HWR and by 13.1 ± 8.5% in LWR. The countermovement jump and 20-m sprint time improved consistently (p <= 0.05) only in HWR, by 2.6 ± 2.5 cm and 0.04 ± 0.04 seconds, respectively. Finally, athletes with a fat percentage of 10% or more at the baseline were able to preserve FFM. In conclusion, altered acid-base balance but improved weight-bearing power performance was observed without negative consequences on serum hormones and FFM after a 4-week weight reduction of 0.5 kg·wk-1 achieved by reduced carbohydrate but maintained high protein intake.