CFP Exercise Science & Physiology 3 — Questions and Answers
Question 1: Which hormone is most responsible for mobilizing free fatty acids from adipose tissue during prolonged low-intensity exercise?
- Insulin
- Glucagon
- Epinephrine (Correct answer)
- Aldosterone
Correct answer: Epinephrine
Epinephrine (adrenaline) activates hormone-sensitive lipase in adipocytes, releasing free fatty acids for use as fuel during prolonged aerobic exercise.
Question 2: The sliding filament theory of muscle contraction states that:
- Myosin filaments shorten during contraction
- Actin filaments lengthen to generate force
- Actin slides over myosin, shortening the sarcomere without filaments changing length (Correct answer)
- ATP is not required once cross-bridges are formed
Correct answer: Actin slides over myosin, shortening the sarcomere without filaments changing length
During contraction, myosin heads pull actin filaments toward the center of the sarcomere, shortening it without the filaments themselves changing length.
Question 3: A client performs 3 sets of 12 reps at 70% 1RM. This protocol primarily targets which training adaptation?
- Maximal strength (neural drive)
- Muscular hypertrophy (Correct answer)
- Power output
- Phosphocreatine resynthesis
Correct answer: Muscular hypertrophy
Moderate loads (67–85% 1RM) with moderate rep ranges (8–12) and multiple sets are the classic stimulus for skeletal muscle hypertrophy.
Question 4: What is the PRIMARY role of calcium (Ca²⁺) in skeletal muscle contraction?
- Provides energy for the power stroke
- Binds troponin to expose actin binding sites for myosin (Correct answer)
- Repolarizes the motor neuron
- Transports ATP into the sarcomere
Correct answer: Binds troponin to expose actin binding sites for myosin
Released from the sarcoplasmic reticulum, Ca²⁺ binds to troponin C, causing tropomyosin to shift and expose actin's myosin-binding sites.
Question 5: Which physiological variable is MOST closely correlated with endurance performance in well-trained athletes?
- VO₂max
- Lactate threshold as a % of VO₂max (Correct answer)
- Resting heart rate
- Maximal heart rate
Correct answer: Lactate threshold as a % of VO₂max
Among athletes with similar VO₂max values, the lactate threshold as a percentage of VO₂max best discriminates endurance performance.
Question 6: The 'all-or-none' principle of muscle contraction refers to:
- A whole muscle either contracting fully or not at all
- An individual motor unit firing maximally or not at all when threshold is reached (Correct answer)
- Oxygen delivery being all-or-none during hypoxia
- ATP being fully consumed before more is produced
Correct answer: An individual motor unit firing maximally or not at all when threshold is reached
When a motor neuron reaches action potential threshold, all muscle fibers in that motor unit contract maximally; they cannot produce a partial response.
Question 7: Which adaptation is MOST associated with long-term aerobic endurance training?
- Increased maximal heart rate
- Decreased resting stroke volume
- Increased mitochondrial density in skeletal muscle (Correct answer)
- Reduced capillary-to-fiber ratio
Correct answer: Increased mitochondrial density in skeletal muscle
Chronic aerobic training significantly increases the number and size of mitochondria in trained muscle fibers, enhancing oxidative capacity.
CFP Exercise Science & Physiology 3
Which hormone is most responsible for mobilizing free fatty acids from adipose tissue during prolonged low-intensity exercise?