Which of the following is a way that muscle fibers get energy needed for contraction? 1) when a muscle is contracting during peak activity, it quickly uses up stored creatine phosphate which was produced during moderate exercise. 2) during moderate exercise, such as jogging on the treadmill, pyruvate and hydrogen ions accumulate causing muscle fatigue. 3) during peak activity levels, glycolysis is the only pathway by which atp can be produced to supply energy to the muscle. 4) because energy demands are low in a resting muscle, a resting muscle is able to meet its atp requirement through glycolysis. 5) aerobic exercise is beneficial to a muscle because it increases muscle's ability to acquire greater amounts of glucose from