The most important reason why muscles tire more quickly during high-intensity workouts than they do during low-intensity workouts is lack of available _____.
A)lactate
B)glucose
C)glycogen
D)oxygen

Question

The most important reason why muscles tire more quickly during high-intensity workouts than they do during low-intensity workouts is lack of available _____. 
A)lactate
B)glucose
C)glycogen
D)oxygen

Quizplus · Accepted Answer

During high-intensity workouts, the body requires more oxygen to produce energy for the muscles. When there is insufficient oxygen, the muscles start to produce energy anaerobically and begin to accumulate lactic acid. This causes fatigue and a burning sensation, leading to decreased muscle performance. Therefore, the lack of available oxygen is the most significant reason why muscles tire more quickly during high-intensity workouts.

The Most Important Reason Why Muscles Tire More Quickly During