Question

multiple choice question

which occurs during high intensity, short-duration exercises that causes fatigue?

adp and phosphate accumulation
calcium accumulation
atp accumulation
acetylcholine accumulation

Explanation:

Analyze exercise duration and fatigue

Using the Muscle Fatigue Mechanisms knowledge point

During high-intensity, short-duration exercise, muscle fibers rely heavily on the rapid breakdown of ATP and creatine phosphate. This rapid rate of ATP hydrolysis leads to a significant accumulation of ADP and free inorganic phosphate (\(\text{P}_i\)) in the sarcoplasm.

Evaluate the physiological consequences

Using the Muscle Fatigue Mechanisms knowledge point

The accumulation of ADP and inorganic phosphate directly contributes to muscle fatigue by:

• Inhibiting calcium release from the sarcoplasmic reticulum.
• Decreasing the sensitivity of myofibrils to calcium.
• Directly interfering with the power stroke of the myosin heads.

Assess the alternative options

Using the Muscle Fatigue Mechanisms knowledge point

• Calcium accumulation: Sarcoplasmic calcium levels typically decline or become less effective during fatigue, rather than accumulating in a way that causes fatigue.
• ATP accumulation: ATP levels are depleted or maintained at a lower steady state; ATP does not accumulate.
• Acetylcholine accumulation: Acetylcholine is rapidly broken down in the synaptic cleft by acetylcholinesterase and does not accumulate to cause fatigue.

Answer:

• (A) ADP and phosphate accumulation (Correct answer)
• (B) Calcium accumulation
• (C) ATP accumulation
• (D) Acetylcholine accumulation