During repetitive high intensity muscle contraction, a point will be reached in which the muscle is unable to continue generating the necessary force to maintain the desired work output. At this point we would consider the muscle to be fatigued. How does fatigue occur?
In your answer,
1) Describe how cross bridges are formed during contraction (i.e., the chemo-mechanical coupling model) and then
2) Discuss the cause of fatigue with specific attention on how the repetitive high intensity contractions induce a depression in pH and elevate Pi.