CPSS Foundations of Exercise Science 2 — Questions and Answers
Question 1: 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 and oxidative enzyme activity, making them highly fatigue-resistant.
Question 2: The sliding filament theory of muscle contraction states that sarcomere shortening occurs because:
- Actin and myosin filaments shorten in length
- Actin filaments slide over myosin filaments toward the M-line
- Myosin filaments slide over actin filaments toward the Z-discs
- Actin slides toward the center while myosin filaments remain stationary (Correct answer)
Correct answer: Actin slides toward the center while myosin filaments remain stationary
In the sliding filament theory, thin actin filaments are pulled toward the M-line (center of the sarcomere) by myosin cross-bridges; neither filament changes length.
Question 3: During maximal aerobic exercise, which cardiovascular adaptation most significantly increases cardiac output?
- Increased stroke volume only
- Increased heart rate only
- Both increased heart rate and stroke volume (Correct answer)
- Decreased peripheral vascular resistance
Correct answer: Both increased heart rate and stroke volume
Maximal cardiac output is achieved through simultaneous increases in both heart rate and stroke volume, with heart rate contributing more at very high intensities.
Question 4: The Fick equation for oxygen consumption (VO2) is expressed as:
- VO2 = HR × SV × (CaO2 − CvO2) (Correct answer)
- VO2 = HR × SV + (CaO2 − CvO2)
- VO2 = (CaO2 − CvO2) / Cardiac Output
- VO2 = SV × (CaO2 + CvO2)
Correct answer: VO2 = HR × SV × (CaO2 − CvO2)
The Fick equation states VO2 = Cardiac Output × arteriovenous oxygen difference (a-vO2 diff), where cardiac output = HR × SV.
Question 5: Which metabolic pathway is the PRIMARY energy source during a 400-meter sprint?
- Phosphocreatine system
- Oxidative phosphorylation
- Glycolytic (lactic acid) system (Correct answer)
- Beta-oxidation of fatty acids
Correct answer: Glycolytic (lactic acid) system
A 400-meter sprint lasting ~45–60 seconds relies predominantly on anaerobic glycolysis, which produces ATP rapidly but also generates lactate.
Question 6: Which hormone is primarily responsible for the acute regulation of blood glucose during prolonged aerobic exercise?
- Cortisol
- Insulin
- Glucagon (Correct answer)
- Epinephrine
Correct answer: Glucagon
Glucagon rises during prolonged exercise to stimulate hepatic glycogenolysis and gluconeogenesis, maintaining blood glucose levels.
Question 7: The respiratory exchange ratio (RER) value of 0.70 at rest indicates the body is primarily oxidizing:
- Carbohydrates
- Proteins
- Mixed substrates
- Fats (Correct answer)
Correct answer: Fats
An RER of 0.70 reflects fat oxidation, since fat metabolism produces 7 CO2 molecules for every 10 O2 consumed (CO2/O2 = 0.70).
CPSS Foundations of Exercise Science 2
Which muscle fiber type has the highest oxidative capacity and is most resistant to fatigue?