SKELETAL MUSCLE CARNOSINE LEVEL MAY CONTRIBUTE TO SUPERIOR PERFORMANCE DURING HIGH INTENSITY EXERCISE

Abstract

Dipeptide carnosine (β-alanyl-L-histidine) has been shown to contribute significantly to physico-chemical buffering in skeletal muscle, which maintains acid-base balance when large quantities of hydrogen ions are produced in association with lactic acid accumulation during high intensity exercise. The purpose of this study was to examine relationships among skeletal muscle carnosine level, fiber type distribution and high intensity exercise performance. The subjects were twenty healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. Carnosine level were determined using an amino acid AutoAnalyzer. Fiber type distribution was determined by staining intensity of myosin adenosinetriphosphatase. High intensity exercise performance was assessed using 30-s cycle ergometer sprinting. Significant (P < 0.05) interrelationships were demonstrated between carnosine level and type II fiber composition. Superior sprint performance was associated with type II fiber composition and carnosine level. When dividing the 30-s sprinting into 6 phases (0–5, 6–10, 11–15, 16–20, 21–25, 26–30 s), significant correlations were observed between carnosine level and mean power of the latter 3 phases (16–20 s: P < 0.05, 21–25 s: P < 0.01 and 26–30 s: P < 0.05). These results indicate that carnosine level may be an important determinant of high intensity exercise performance.