ACSM Exercise Science Practice Questions — 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.
Question 8: Which assessment is used to estimate cardiorespiratory fitness without maximal exertion and is based on heart rate response?
- Rockport Walk Test
- Margaria-Kalamen Step Test
- YMCA Submaximal Cycle Ergometer Test (Correct answer)
- Wingate Anaerobic Test
Correct answer: YMCA Submaximal Cycle Ergometer Test
The YMCA Submaximal Cycle Ergometer Test estimates VO2max by extrapolating the linear heart rate-workload relationship to predicted maximal heart rate.
Question 9: What is the primary fuel source during low-intensity, prolonged exercise (e.g., 30–50% VO2max)?
- Muscle glycogen
- Blood glucose
- Free fatty acids (Correct answer)
- Phosphocreatine
Correct answer: Free fatty acids
At low intensities, the aerobic system relies predominantly on free fatty acid oxidation, sparing glycogen for higher-intensity demands.
Question 10: What is the Frank-Starling mechanism and its significance in exercise physiology?
- Arterial vasoconstriction reduces afterload during exercise
- Increased venous return stretches the ventricle, increasing stroke volume (Correct answer)
- Heart rate increases with sympathetic stimulation
- Oxygen extraction increases at the muscle level
Correct answer: Increased venous return stretches the ventricle, increasing stroke volume
The Frank-Starling mechanism describes how increased venous return during exercise stretches ventricular walls, enhancing contractility and stroke volume.
Question 11: Which type of stretching is most recommended for improving flexibility and is generally considered the safest for most populations?
- Ballistic stretching
- PNF stretching
- Static stretching (Correct answer)
- Dynamic stretching
Correct answer: Static stretching
Static stretching, involving holding a position for 15–60 seconds, is widely recommended for improving flexibility with a low injury risk profile.
Question 12: During high-intensity interval training (HIIT), which metabolic byproduct is primarily responsible for the burning sensation in muscles?
- Carbon dioxide
- Lactic acid accumulation and hydrogen ion production (Correct answer)
- Free radical generation
- Ammonia from protein catabolism
Correct answer: Lactic acid accumulation and hydrogen ion production
The burning sensation during intense exercise is caused by hydrogen ion accumulation (from lactate production), which decreases muscle pH and impairs contraction.
Question 13: What is the recommended minimum number of days per week of moderate-intensity aerobic exercise for substantial health benefits according to ACSM guidelines?
- 2 days/week
- 3 days/week
- 5 days/week (Correct answer)
- 7 days/week
Correct answer: 5 days/week
ACSM recommends ≥5 days/week of moderate-intensity aerobic activity, or ≥3 days/week of vigorous-intensity activity, for substantial health benefits.
Question 14: Which variable is calculated by multiplying heart rate by stroke volume?
- Oxygen pulse
- Mean arterial pressure
- Cardiac output (Correct answer)
- Rate pressure product
Correct answer: Cardiac output
Cardiac output (Q) = heart rate (HR) × stroke volume (SV), representing the total volume of blood ejected by the heart per minute.
