ACSM Exercise Physiology 2

Question 1

Which energy system predominantly fuels a 400-meter sprint run?

Accepted Answer

Glycolytic (lactic acid) system

Answer

The 400-meter sprint (~45–60 seconds) relies primarily on fast glycolysis (lactic acid system) for ATP production.

Question 2

During incremental exercise to exhaustion, blood lactate concentration begins to rise sharply at the lactate threshold because:

Accepted Answer

Lactate production exceeds clearance capacity

Answer

At the lactate threshold, fast-twitch fiber recruitment and accelerated glycolysis cause lactate production to exceed peripheral clearance.

Question 3

Stroke volume typically reaches its plateau during upright cycle ergometry at approximately what percentage of VO2max?

Accepted Answer

40–60%

Answer

Stroke volume plateaus at roughly 40–60% of VO2max during upright exercise, after which further cardiac output increases rely on heart rate.

Question 4

The primary role of 2,3-bisphosphoglycerate (2,3-BPG) during prolonged exercise is to:

Accepted Answer

Facilitate oxygen release from hemoglobin to muscles

Answer

2,3-BPG binds to deoxyhemoglobin, reducing oxygen affinity and promoting O2 unloading in metabolically active tissues.

Question 5

Which muscle fiber type has the highest oxidative capacity and fatigue resistance?

Accepted Answer

Type I

Answer

Type I (slow-twitch) fibers have the most mitochondria and oxidative enzymes, making them highly resistant to fatigue.

ACSM Practice Test