Metabolic responses to international freestyle wrestling were investigated in six university wrestlers, four of whom were studied on two separate occasions. Lactate concentration in venous blood averaged 10.5 mM after the six minute bouts, while blood pH was (p less than 0.01) reduced to 7.063 +/- 0.061 (mean +/- S.D.) after wrestling. Glycogen concentration in biopsy samples from the vastus lateralis muscle was lower by 10.0 +/- 4.4 mmoles glucose units/kg wet muscle weight (p less than 0.01) after, compared to before wrestling. Evaluation of glycogen utilization in individual muscle fibre types using the periodic acid Schiff histochemical stain revealed that glycogen depletion, although modest, was similar in ST, FTa and FTb fibres. These data demonstrate that wrestling involves significant anaerobic metabolism, and that the vastus lateralis muscle is significantly involved in wrestling performance.