Abstract des Autors

Acute body mass loss >2% has been associated with an impairment of exercise performance, particularly in hot conditions. The aim of this study was to investigate hydration status over a period of training and competing in the New Zealand Football Championship league during the summer. Daily hydration status was determined by urine specific gravity (USG) from first void urine samples collected over 8 days, including 4 days of training and 1 day of competition. Acute changes in hydration status as a result of training and competition were estimated from body mass change. Sweat loss was calculated from body mass change taking into account fluid intake and urinary loss. Mean net change in body mass during training for all players who completed training (n=12) was +0.40 ± 0.75% and all who completed a full game (n=7) was -3.02 ± 1.08%. Mean net body mass change in players who completed both training and competition (n=5) was -1.03 ± 0.28% and -3.45 ± 0.96%, respectively. Body mass change, fluid intake, sweat loss and sweat rate were greater (P < 0.05) during competition than training in those who completed both. Players were hypohydrated (USG > 1.020) on all mornings except competition day. Training did not affect hydration status, as indicated by USG the following morning. Hydration status across an extended period of repeated training and competition appears to be suboptimal. Net fluid balance during training and competition is highly variable, with some players overhydrating in training. Acute body mass loss is inevitable with football and is best managed by individualized drinking strategies that prevent weight gain or large loss during training and competition. Monitoring daily hydration status prior to subsequent endeavor may help maintain euhydration. Verf.-Referat