Final answer:
Muscle protein breakdown is part of muscle recovery and building post-exercise. While the immediate energy needs are covered by creatine phosphate and glycolysis, the repair processes last for a longer duration. Based on available information, an educated estimate would suggest that muscle protein breakdown increases for around 4 hours after high-intensity resistance exercise.
Step-by-step explanation:
After a bout of high-intensity resistance exercise, muscle protein breakdown is increased for a significant period. This response is part of the body's mechanisms for adapting and building stronger muscle tissue. When muscle tissues are heavily taxed by resistance exercise, there is both an immediate demand for ATP and subsequent processes that lead to repair and growth. Initially, ATP is supplied by creatine phosphate for about 15 seconds, and then through anaerobic respiration, which produces lactic acid and can lead to muscle fatigue. Beyond initial energy supply, the body increases oxygen supply for aerobic respiration, which dominates the recovery and muscle-building processes after exercise. Given the context provided, delayed onset muscle soreness (DOMS) typically sets in one to three days post-exercise, and lactic acid is cleared relatively quickly, indicating that the period of increased muscle protein breakdown likely extends beyond merely minutes.
While the exact answer is not provided explicitly in the information given, an educated estimation based on the nature of muscle recovery and adaptation mechanisms, which are initiated after strenous exercise, would lead one to presume that the period of increased muscle protein breakdown likely lasts longer than options a and b, perhaps closer to 4 hours (option d), as the body initiates repairs and enhances muscle-building in response to the high-intensity workout.