ACSM Exercise Science 2 — Questions and Answers
Question 1: Which energy system predominates during a 400-meter sprint lasting approximately 50-60 seconds?
- Phosphocreatine system
- Anaerobic glycolysis (Correct answer)
- Oxidative phosphorylation
- Beta-oxidation
Correct answer: Anaerobic glycolysis
Anaerobic glycolysis is the primary energy system for high-intensity efforts lasting 30–120 seconds, such as a 400-meter sprint.
Question 2: What is the primary role of the Golgi tendon organ (GTO) during muscle contraction?
- Detect changes in muscle length
- Sense joint position
- Inhibit excessive muscle tension (Correct answer)
- Stimulate antagonist muscles
Correct answer: Inhibit excessive muscle tension
The GTO detects high tension in tendons and triggers autogenic inhibition to protect muscles and tendons from excessive force.
Question 3: During aerobic exercise, what happens to arteriovenous oxygen difference (a-vO2 diff) as intensity increases?
- It decreases
- It remains unchanged
- It increases (Correct answer)
- It fluctuates unpredictably
Correct answer: It increases
As exercise intensity increases, working muscles extract more oxygen, widening the a-vO2 difference.
Question 4: Which muscle fiber type has the highest oxidative capacity and is most resistant to fatigue?
- Type IIx
- Type IIa
- Type I (Correct answer)
- Type IIb
Correct answer: Type I
Type I (slow-twitch) fibers are densely packed with mitochondria and myoglobin, making them highly oxidative and fatigue-resistant.
Question 5: What is the typical respiratory exchange ratio (RER) value that indicates predominant fat oxidation at rest?
- 1.00
- 0.85
- 0.70 (Correct answer)
- 1.10
Correct answer: 0.70
An RER of approximately 0.70 indicates that fat is the primary fuel source, reflecting the VCO2/VO2 ratio of fatty acid oxidation.
Question 6: Which of the following best describes the force-velocity relationship in skeletal muscle?
- Force and velocity increase proportionally together
- As contraction velocity increases, force production decreases (Correct answer)
- Force is unaffected by velocity
- Velocity determines fiber type recruitment only
Correct answer: As contraction velocity increases, force production decreases
The force-velocity relationship shows an inverse relationship: as shortening velocity increases, the maximum force a muscle can produce decreases.
Question 7: Which cardiac adaptation is most associated with chronic endurance training?
- Increased left ventricular wall thickness
- Increased left ventricular end-diastolic volume (Correct answer)
- Elevated resting heart rate
- Reduced stroke volume
Correct answer: Increased left ventricular end-diastolic volume
Endurance training causes eccentric hypertrophy, increasing left ventricular chamber volume and stroke volume at rest and during exercise.
ACSM Exercise Science 2
Which energy system predominates during a 400-meter sprint lasting approximately 50-60 seconds?