A boxer has been jumping rope for an hour. His leg muscles are burning and he feels weak. Which of the following most likely explains the burning he feels in his muscles?

Lactate buildup 10.0%

Anaerobic respiration takes place when you demand your muscles to do vigorous work. Normally, aerobic respiration takes place but when energy is needed immediately, anaerobic respiration takes place. During anaerobic respiration, the body produces lactic acid, which leads to the burning sensation. Your lungs deliver oxygen to the muscles much slower than the rate you need, since you're putting your muscles through an extensive exercise, and this leads to muscle fatigue.