Exercise Science Principles Flashcards

Which energy system predominates during a 400-meter sprint performed at maximal effort?

Answer: Fast glycolysis

A 400-meter sprint lasting approximately 45–60 seconds relies predominantly on fast glycolysis (anaerobic glycolysis) for ATP production.

The Fick equation for oxygen consumption (VO2) is best expressed as:

Answer: VO2 = HR × SV × (a-vO2 difference)

The Fick equation states VO2 = cardiac output (HR × SV) multiplied by the arteriovenous oxygen difference (a-vO2 diff).

During eccentric muscle contractions, force production relative to maximal isometric force is:

Answer: Higher

Eccentric contractions can produce forces 20–60% greater than maximal isometric force due to passive elastic contributions of titin and cross-bridge mechanics.

Which muscle fiber type has the highest oxidative capacity and is most resistant to fatigue?

Answer: Type I

Type I (slow-twitch) fibers have the highest mitochondrial density, oxidative enzyme activity, and fatigue resistance.

The sliding filament theory describes muscle contraction as:

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.

Oxygen debt (excess post-exercise oxygen consumption, EPOC) is primarily caused by:

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.

Which of the following best describes the length-tension relationship in skeletal muscle?

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 (~2.0–2.2 μm) where the number of possible actin-myosin cross-bridges is maximized.