NSCA CSCS Exercise Science Principles 2 â Questions and Answers
Question 1: Which energy system predominates during a 400-meter sprint performed at maximal effort?
- Phosphagen system
- Fast glycolysis (Correct answer)
- Slow glycolysis
- Oxidative phosphorylation
Correct answer: Fast glycolysis
A 400-meter sprint lasting approximately 45â60 seconds relies predominantly on fast glycolysis (anaerobic glycolysis) for ATP production.
Question 2: The Fick equation for oxygen consumption (VO2) is best expressed as:
- VO2 = HR Ã SV Ã (a-vO2 difference) (Correct answer)
- VO2 = HR Ã SV Ã ejection fraction
- VO2 = cardiac output / (a-vO2 difference)
- VO2 = stroke volume à heart rate only
Correct answer: VO2 = HR Ã SV Ã (a-vO2 difference)
The Fick equation states VO2 = cardiac output (HR Ã SV) multiplied by the arteriovenous oxygen difference (a-vO2 diff).
Question 3: During eccentric muscle contractions, force production relative to maximal isometric force is:
- Lower
- Equal
- Higher (Correct answer)
- Highly variable with no consistent trend
Correct answer: Higher
Eccentric contractions can produce forces 20â60% greater than maximal isometric force due to passive elastic contributions of titin and cross-bridge mechanics.
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 have the highest mitochondrial density, oxidative enzyme activity, and fatigue resistance.
Question 5: The sliding filament theory describes muscle contraction as:
- Actin and myosin filaments shortening in length
- Actin filaments sliding over myosin filaments to shorten the sarcomere (Correct answer)
- Myosin filaments elongating to pull Z-lines apart
- Cross-bridges rotating to push Z-lines outward
Correct answer: Actin filaments sliding over myosin filaments to shorten the sarcomere
During contraction, actin (thin) filaments slide past myosin (thick) filaments, reducing sarcomere length without the filaments themselves changing length.
Question 6: Oxygen debt (excess post-exercise oxygen consumption, EPOC) is primarily caused by:
- Glycogen resynthesis alone
- Restoration of phosphocreatine, removal of lactate, elevated temperature, and hormonal effects (Correct answer)
- Increased carbon dioxide removal during recovery
- Decreased cardiac output post-exercise
Correct answer: Restoration of phosphocreatine, removal of lactate, elevated temperature, and hormonal effects
EPOC reflects multiple recovery processes including PCr replenishment, lactate clearance, elevated body temperature, and circulating catecholamines.
Question 7: Which of the following best describes the length-tension relationship in skeletal muscle?
- Force is greatest at very short sarcomere lengths due to maximum cross-bridge overlap
- Maximum force is produced at an intermediate (optimal) sarcomere length where actin-myosin overlap is ideal (Correct answer)
- Force production increases linearly as sarcomere length increases
- Force is greatest at maximum sarcomere stretch due to passive tension alone
Correct answer: Maximum force is produced at an intermediate (optimal) sarcomere length where actin-myosin overlap is ideal
Peak active force occurs at optimal sarcomere length (~2.0â2.2 Ξm) where the number of possible actin-myosin cross-bridges is maximized.
NSCA CSCS Exercise Science Principles 2
Which energy system predominates during a 400-meter sprint performed at maximal effort?