Strength training effects on aerobic power and short-term endurance.

Nine men participated in an exercise program (five days a week for 10 weeks) that was designed to strengthen the quadriceps muscles. This study was undertaken to determine if heavy resistance training results in an increase in endurance, Vo2max and whether the differences that are normally observed during bicycle and treadmill Vo2max measurements in the same individuals are strength-related. Following training, endurance time to exhaustion significantly increased while cycling (47%) and while running (12%), when the subjects exercised at 100% of their pretraining Vo2max. There was a small increase in Vo2max (4%, P < 0.05) during bicycle exercise (3.40 l.min-1 to 3.54 l.min-1) after training, but no significant differences were observed when expressed in (ml.kg-1.min-1). Strength training had no effect on Vo2max when measured during treadmill exercise. Absolute differences between bicycle and treadmill Vo2max were essentially the same after training as before. Lactate concentration in blood after the bicycle and treadmill endurance tests were not elevated to a greater extent after training. Thigh girth increased significantly and muscle strength increased 40% with the training. These findings provide evidence that HRT is capable of dramatically increasing short-term endurance, when the muscles involved in the training are used almost exclusively during the testing without an accompanying increase in Vo2max. These data also suggest that the differences in Vo2max between bicycle and treadmill exercise are not the result of inadequate muscle strength.