Oxygen uptake in active skeletal muscle
Elder, Christopher Paul
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Previous investigators have predicted oxygen uptake per kilogram muscle mass in humans during dynamic knee extension. The limitation to these predictions is the inability to effectively quantify active muscle. The purpose of this study was to quantify active muscle during dynamic knee extension and isometric exercise under aerobic conditions with T2 relaxation times and arrive at a better estimate of VO2.per kilogram active muscle using young healthy volunteers, a modified Krogh ergometer, MRI, electrical stimulation, and whole body VO2. VO2 per kilogram active muscle for two-legged knee extension was 724 ± 132 ml • kg -1 • min -1 ; one-legged knee extension 618 ± 135 ml • kg -1 • min -1 ; and two legged isometric exercise 320 ± 76 ml • kg -1 • min -1 . VO2 per kilogram active muscle is at least 60 percent higher than previous estimates, is independent of muscle mass active, and is much lower during isometric than dynamic exercise.