Question

se intensity increases, stroke Volume ange ase directly with intensity ease and level off crease directly with intensity UESTION 100 Following 10 weeks of aerobic exercise training, it is most likely that the lactate threshold will: A. Stay the same B. Shift to the right C. Shift to the left D. Move downward Click Save and Submit to save and submit. Click Save All Answers to save all answers MacBook Air

Answer 1

B.

Lactate is the primary by-product of the anaerobic glycolytic energy system. At lower exercise intensi- ties, when the cardiorespiratory system can meet the oxygen demands of active muscles, blood lactate levels remain close to those observed at rest, because some lactate is used aerobically by muscle and is removed as fast as it enters the blood from the muscle. As the intensity of exercise is increased, however, the rate of lactate entry into the blood from muscle eventually exceeds its rate of removal from the blood, and blood lactate concentrations increase above resting levels. From this point on, lactate levels continue to increase as the rate of work in- creases, until the point of exhaustion. The point at which the concentration of lactate in the blood begins to increase above resting levels is referred to as the lactate threshold

Lactate threshold is an important marker for endur- ance performance, because distance runners set their race pace at or slightly above the lactate threshold (Farrell et al. 1979). Further, the lactate thresholds of highly trained endurance athletes occur at a much higher percentage of their V ̇ O2max, and thus at higher relative workloads, than do the thresholds of un- trained persons. This key difference is what allows endurance athletes to perform at a faster pace.