THE INFLUENCE OF MAXIMAL AEROBIC POWER ON RECOVERY OF SKELETAL-MUSCLEFOLLOWING ANAEROBIC EXERCISE

Phosphorus magnetic resonance spectroscopy (P-31-MRS) was used to inve stigate the influence of maximal aerobic power (VO2max) on the recover y of human calf muscle from high-intensity exercise. The ((V) over dot O-2max) of 21 males was measured during treadmill exercise and subjec ts were assigned to either a low-aerobic-power (LAP) group (n=10) or a high-aerobic-power (HAP) group (n=11). Mean (SE) (V)over dot O-2max o f the groups were 46.6 (1.1) and 64.4 (1.4) ml.kg(-1).min(-1), respect ively. A calf ergometry work capacity test was used to assign the same relative exercise intensity to each subject for the MRS protocol. At least 48 h later subjects performed the rest (4 min) exercise (2 min) and recovery (10 min) protocol in a 1.5 T MRS scanner. The relative co ncentration of phosphocreatine (PCr) was measured throughout the proto col and intracellular pH (pH(i)) was determined from the chemical shif t between inorganic phospate (P-i) and PCr. End-exercise PCr levels we re 27 (3.4) and 25 (3.5)% of resting levels for LAP and HAP respective ly. Mean resting pH(i) was 7.07 for both groups, and following exercis e it fell to 6.45 (0.04) for HAP and 6.38 (0.04) for LAP. Analysis of data using non-linear regression models showed no differences in the r ate of either PCr or pH(i) recovery. The results suggest that (V)over dot O-2max is a poor predictor of metabolic recovery rate from high-in tensity exercise. Differences in recovery rate observed between indivi duals with similar (V) over dot O-2max imply that other factors influe nce recovery.