EFFECTS OF RAPID WEIGHT-LOSS AND WRESTLING ON MUSCLE GLYCOGEN CONCENTRATION

Objective: To examine the effect of energy restriction and wrestling o n muscle glycogen content in highly-trained male wrestlers. Design: Ra ndomized, unblinded intervention trial. Setting: McMaster University N utrition and Metabolism Research Laboratory. Participants: Twelve high ly trained male wrestlers volunteered as subjects and were randomly as signed to one of two groups (Group A, n = 6; Group B, n = 6) as define d below. Assessment of risk factors: All subjects were free of medical conditions that would preclude participation in the study and all had performed rapid weight loss at least three times/year with no medical complications. Interventions: Group A: simulated wrestling tournament , four 5-min wrestling bouts (>7 h) following a 5% body weight loss an d 17 h repletion period; Group B: 5% weight loss through energy restri ction (1,141 kcal/day), exercise, fluid restriction, and dehydration m ethods (sauna) >72 h. Main outcome measures: Group A: muscle glycogen content before and after wrestling tournament and plasma lactate after each bout; Group B: muscle glycogen before and after weight loss. Res ults: Group A: no significant effect on muscle glycogen concentration, yet large increases were observed in blood lactate concentrations (up to 14.7 mmol/L); Group B: weight loss resulted in a 54% (p < 0.018) r eduction in muscle glycogen concentration. Conclusions: The weight los s methods commonly performed by wrestlers resulted in large decreases in muscle glycogen concentration that were largely reversed during the 17-h repletion period between weigh-in and the start of the competiti on; participation in a wrestling tournament did not have a significant impact upon biceps brachii glycogen concentration when ad libitum fee ding is allowed between matches.