CPSS Foundations of Exercise Science 3 — Questions and Answers
Question 1: Which of the following best describes the term 'motor unit'?
- A single muscle fiber and its associated sarcomeres
- A motor neuron and all the muscle fibers it innervates (Correct answer)
- The neuromuscular junction between one neuron and one fiber
- A group of motor neurons located in the spinal cord
Correct answer: A motor neuron and all the muscle fibers it innervates
A motor unit consists of a single alpha motor neuron and all the muscle fibers it innervates, which contract together upon stimulation.
Question 2: According to the size principle of motor unit recruitment, motor units are recruited in order of:
- Decreasing size, from large to small
- Random order depending on movement type
- Increasing size, from smallest to largest (Correct answer)
- Alternating between fast and slow fibers
Correct answer: Increasing size, from smallest to largest
Henneman's size principle states that smaller, low-threshold motor units (Type I) are recruited first, with larger motor units (Type II) activated as force demands increase.
Question 3: What is the primary role of the muscle spindle during a rapid stretch of a muscle?
- Inhibit antagonist muscles via reciprocal inhibition
- Signal Golgi tendon organs to prevent injury
- Detect the rate and magnitude of muscle stretch and initiate a reflex contraction (Correct answer)
- Store elastic energy for subsequent concentric contractions
Correct answer: Detect the rate and magnitude of muscle stretch and initiate a reflex contraction
Muscle spindles (intrafusal fibers) sense changes in muscle length and stretch velocity, triggering the stretch reflex to resist further elongation.
Question 4: During submaximal steady-state aerobic exercise, which substrate provides the majority of ATP after 90+ minutes when glycogen is depleted?
- Muscle phosphocreatine
- Plasma free fatty acids (Correct answer)
- Blood glucose only
- Branched-chain amino acids
Correct answer: Plasma free fatty acids
As muscle glycogen depletes, plasma free fatty acids mobilized from adipose tissue become the dominant fuel via beta-oxidation.
Question 5: Which of the following best describes 'excess post-exercise oxygen consumption' (EPOC)?
- Reduced oxygen consumption during recovery to conserve energy
- Elevated VO2 above resting baseline during recovery to restore homeostasis (Correct answer)
- Increased ventilation during exercise to meet oxygen demands
- Additional oxygen stored in myoglobin after intense exercise
Correct answer: Elevated VO2 above resting baseline during recovery to restore homeostasis
EPOC represents the elevated oxygen uptake following exercise used to restore phosphocreatine, clear lactate, normalize temperature, and re-oxygenate blood.
Question 6: The lactate threshold (LT1) physiologically represents:
- The exercise intensity at which VO2max is first achieved
- The point where blood lactate begins to accumulate faster than it is cleared (Correct answer)
- The maximum lactate the muscle can produce per unit time
- The onset of anaerobic metabolism in all active muscle fibers
Correct answer: The point where blood lactate begins to accumulate faster than it is cleared
LT1 marks the intensity where lactate production begins to exceed clearance capacity, causing blood lactate to rise above baseline levels.
Question 7: Which connective tissue structure directly connects muscle to bone?
- Ligament
- Fascia
- Aponeurosis
- Tendon (Correct answer)
Correct answer: Tendon
Tendons are composed primarily of type I collagen and transmit the force generated by muscle contraction to the skeletal system.
CPSS Foundations of Exercise Science 3
Which of the following best describes the term 'motor unit'?