EHS 385 Lecture Notes - Lecture 14: Phosphorylase, Vo2 Max, Gluconeogenesis

• School: UMass Boston
• Department: Exercise and Health Science
• Course: EHS 385
• Professor: Rachel Drew

Document Summary

Blood lactate rises rapidly during incremental exercise: 50-60% vo2 max untrained, 65-80% vo2 max in trained, best predictor of endurance performance. Also called anaerobic threshold, onset of blood lactate accumulation (obla), exercise intensity at which blood lactate level reaches 4 mmol/l. Accelerated glycolysis: increase in epinephrine/norepinephrine, nadh produced faster in sarcoplasm than shuttled into mitochondria, so excess nadh in sarcoplasm converts pyruvate to lactate. Recruitment fast-twitch muscle fibers: lactate dehydrogenase (ldh) isozyme (different form of same enzyme) in fast-twitch promotes lactate formation. Reduced rate of lactate removal from blood. Prediction of performance, combined with vo2 max. Plan training programs, marker of training intensity, choose heart rate based on lactate threshold. Lactate production believed to cause delayed-onset muscle soreness (doms) that occurs 24-48 hr following exercise. Physiological evidence does not support claim: lactate removal rapid (within 60 mins) following exercise, if lactate caused soreness, power athletes (sprinters) would experience doms after every workout (soreness rare following routine workout)