Exercise Physiology & Energy Metabolism Flashcards

Which metabolic adaptation MOST distinguishes skeletal muscle of a highly trained endurance athlete compared to an untrained individual?

Answer: Greater intramuscular triglyceride (IMTG) stores and enhanced lipid oxidation capacity

Endurance training increases IMTG content and upregulates lipid oxidative enzymes, enabling the athlete to oxidize fat at higher absolute workloads and spare glycogen.

Excess post-exercise oxygen consumption (EPOC) after high-intensity exercise is PRIMARILY driven by:

Answer: Resynthesis of phosphocreatine, lactate clearance, elevated temperature, and hormonal effects

EPOC results from multiple oxygen-consuming processes: PCr resynthesis, lactate-to-glycogen conversion, elevated core temperature, and catecholamine-driven elevation of metabolic rate.

During altitude acclimatization, which metabolic shift occurs that affects carbohydrate and fat utilization?

Answer: Initial increased reliance on carbohydrate due to hypoxia-induced AMPK activation and PDH upregulation

Hypoxia activates AMPK and pyruvate dehydrogenase, shifting substrate preference toward carbohydrate oxidation because fat oxidation requires more oxygen per ATP produced.

Which concept explains why athletes performing concurrent training (strength + endurance) may see blunted strength gains compared to strength training alone?

Answer: AMPK-mTOR interference, where AMPK activated by endurance work suppresses mTORC1-driven hypertrophy signaling

Endurance exercise activates AMPK, which can phosphorylate and inhibit mTORC1, the primary anabolic signaling hub for muscle protein synthesis and hypertrophy.

A female soccer player in a prolonged energy deficit shows blunted resting metabolic rate (RMR). This adaptation is MOST consistent with:

Answer: Metabolic adaptation (adaptive thermogenesis) reducing RMR below predicted values

Chronic low energy availability triggers adaptive thermogenesis, suppressing RMR below predictions based on lean mass, consistent with Relative Energy Deficiency in Sport (RED-S).

Which measure BEST reflects an athlete's anaerobic power output capacity during a single explosive effort?

Answer: Peak power output on a Wingate test (Watts/kg)

Peak power on the Wingate anaerobic test represents maximal short-duration power output and reflects phosphocreatine and early glycolytic energy system capacity.

During resistance exercise, the primary energy system supporting a 3-set hypertrophy protocol (8–12 reps, 60–75% 1RM, 60-second rest) is:

Answer: A combination of phosphocreatine and glycolysis with limited aerobic contribution

The relatively short set duration and incomplete rest recovery characteristic of hypertrophy protocols rely predominantly on PCr resynthesis between sets supplemented by rapid glycolysis during sets.