ACE Exercise Physiology 1 — Questions and Answers
Question 1: Which energy system is the PRIMARY source of ATP during a 100-meter sprint?
- Oxidative phosphorylation
- Phosphocreatine (ATP-PC) system (Correct answer)
- Glycolytic system
- Beta-oxidation
Correct answer: Phosphocreatine (ATP-PC) system
The ATP-PC (phosphocreatine) system provides immediate, high-power energy for very short, maximal-intensity efforts lasting up to about 10 seconds.
Question 2: What is the term for the maximum amount of oxygen the body can consume per minute during maximal exercise?
- Lactate threshold
- VO2 max (Correct answer)
- Oxygen pulse
- Respiratory exchange ratio
Correct answer: VO2 max
VO2 max (maximal oxygen uptake) represents the ceiling of the cardiorespiratory system's ability to deliver and use oxygen during intense exercise.
Question 3: During prolonged, low-intensity exercise, which fuel source becomes increasingly predominant?
- Muscle glycogen
- Blood glucose
- Fat (free fatty acids) (Correct answer)
- Protein
Correct answer: Fat (free fatty acids)
At low intensities, the oxidative system has time to metabolize fat (free fatty acids), making fat the dominant fuel source during prolonged, easy-paced activity.
Question 4: Which of the following best describes the 'lactate threshold'?
- The point at which lactic acid production completely stops
- The exercise intensity at which lactate begins to accumulate faster than it can be cleared (Correct answer)
- The maximum heart rate achievable during exercise
- The intensity at which carbohydrate use stops
Correct answer: The exercise intensity at which lactate begins to accumulate faster than it can be cleared
Lactate threshold is the intensity where lactate production exceeds clearance, causing blood lactate to rise rapidly, typically signaling a shift to heavier anaerobic metabolism.
Question 5: The Frank-Starling mechanism states that cardiac output increases because:
- Heart rate rises proportionally with exercise intensity
- Greater ventricular filling (preload) leads to a more forceful contraction (Correct answer)
- Blood pressure decreases during exercise
- Stroke volume is fixed regardless of filling volume
Correct answer: Greater ventricular filling (preload) leads to a more forceful contraction
The Frank-Starling mechanism describes how increased end-diastolic volume stretches the ventricles, causing a stronger contraction and greater stroke volume.
Question 6: Which hormone is primarily responsible for the breakdown of glycogen into glucose during high-intensity exercise?
- Insulin
- Glucagon
- Epinephrine (adrenaline) (Correct answer)
- Cortisol
Correct answer: Epinephrine (adrenaline)
Epinephrine is rapidly released by the adrenal medulla during intense exercise and strongly stimulates glycogenolysis (glycogen breakdown) in liver and muscle.
Question 7: What is 'excess post-exercise oxygen consumption' (EPOC) primarily attributed to?
- Increased fat storage after exercise
- Elevated oxygen demand to restore homeostasis after exercise (Correct answer)
- Decreased metabolic rate during recovery
- Immediate glycogen synthesis
Correct answer: Elevated oxygen demand to restore homeostasis after exercise
EPOC reflects the elevated oxygen consumption above resting levels that occurs after exercise to restore metabolic processes such as re-synthesizing ATP, clearing lactate, and returning body temperature to normal.
ACE Exercise Physiology 1
Which energy system is the PRIMARY source of ATP during a 100-meter sprint?