BHK Exercise Physiology 1 — Questions and Answers
Question 1: What is the primary energy system used during a 100-meter sprint?
- Oxidative phosphorylation
- ATP-PCr system (Correct answer)
- Glycolytic system
- Beta-oxidation
Correct answer: ATP-PCr system
The ATP-PCr (phosphocreatine) system provides immediate energy for maximal efforts lasting under 10 seconds.
Question 2: Which term describes the maximum amount of oxygen the body can utilize during intense exercise?
- Anaerobic threshold
- Respiratory exchange ratio
- VO2 max (Correct answer)
- Oxygen debt
Correct answer: VO2 max
VO2 max is the maximal oxygen uptake and is considered the gold standard measure of cardiorespiratory fitness.
Question 3: What happens to stroke volume during progressive aerobic exercise in a trained individual?
- It decreases steadily
- It remains constant throughout
- It increases then plateaus near maximal intensity (Correct answer)
- It increases linearly with no plateau
Correct answer: It increases then plateaus near maximal intensity
Stroke volume increases with exercise intensity but plateaus at approximately 40–60% of VO2 max in trained individuals.
Question 4: Which muscle fiber type is most resistant to fatigue and relies predominantly on oxidative metabolism?
- Type IIx
- Type IIa
- Type I (Correct answer)
- Type IIb
Correct answer: Type I
Type I (slow-twitch) fibers have high mitochondrial density and capillary supply, making them highly fatigue-resistant.
Question 5: The lactate threshold is best described as the exercise intensity at which:
- Muscle glycogen is completely depleted
- Blood lactate begins to accumulate faster than it is cleared (Correct answer)
- Oxygen consumption reaches its maximum
- Fat oxidation exceeds carbohydrate oxidation
Correct answer: Blood lactate begins to accumulate faster than it is cleared
The lactate threshold marks the point where lactate production exceeds clearance, causing blood lactate to rise exponentially.
Question 6: Which hormone is primarily responsible for increasing blood glucose during exercise by stimulating glycogenolysis in the liver?
- Insulin
- Cortisol
- Glucagon (Correct answer)
- Aldosterone
Correct answer: Glucagon
Glucagon rises during exercise and stimulates hepatic glycogenolysis to maintain blood glucose availability for working muscles.
BHK Exercise Physiology 1
What is the primary energy system used during a 100-meter sprint?