Schwinn Bike Energy Systems 2 — Questions and Answers
Question 1: During a prolonged indoor cycling class at moderate intensity, which fuel source does the body preferentially burn after glycogen stores are partially depleted?
- Creatine phosphate
- Free fatty acids (Correct answer)
- Dietary protein
- Lactic acid
Correct answer: Free fatty acids
At moderate intensities with depleted glycogen, the body increasingly oxidizes free fatty acids via the aerobic system.
Question 2: Which metabolic byproduct accumulates when exercise intensity exceeds the lactate threshold?
- Carbon dioxide
- Pyruvate
- Lactate and hydrogen ions (Correct answer)
- Acetyl-CoA
Correct answer: Lactate and hydrogen ions
Above lactate threshold, lactate and hydrogen ions accumulate faster than they can be cleared, contributing to fatigue.
Question 3: In an indoor cycling class, a 20-second all-out sprint primarily taxes which energy system?
- Oxidative phosphorylation
- Glycolytic system
- Phosphagen system (Correct answer)
- Beta-oxidation
Correct answer: Phosphagen system
Maximal efforts under 10–15 seconds are fueled almost entirely by the phosphagen (ATP-PCr) system.
Question 4: What term describes the point during exercise at which the body shifts from predominantly aerobic to anaerobic energy production?
- VO2 max
- Lactate threshold (Correct answer)
- Respiratory exchange ratio
- Oxygen deficit
Correct answer: Lactate threshold
The lactate threshold marks the intensity at which anaerobic glycolysis begins contributing significantly to energy production.
Question 5: Which of the following best describes the aerobic oxidative system's primary advantage over anaerobic systems?
- Fastest ATP production rate
- Unlimited energy yield without fatigue-causing byproducts (Correct answer)
- No need for oxygen
- Relies solely on carbohydrates
Correct answer: Unlimited energy yield without fatigue-causing byproducts
The aerobic system can produce large amounts of ATP using fats and carbs without accumulating fatigue-inducing byproducts like hydrogen ions.
Question 6: An instructor programs a 45-minute endurance ride at 65% of maximum heart rate. This intensity primarily trains which energy pathway?
- Phosphagen system
- Fast glycolysis
- Aerobic oxidative system (Correct answer)
- Alactic anaerobic system
Correct answer: Aerobic oxidative system
Sustained moderate-intensity exercise at ~65% HRmax predominantly relies on the aerobic oxidative system for ATP production.
Question 7: Which molecule serves as the direct currency of energy in all three energy systems?
- Glucose
- ATP (Correct answer)
- NADH
- Glycogen
Correct answer: ATP
ATP (adenosine triphosphate) is the universal energy currency used directly by muscles to perform mechanical work.
Schwinn Bike Energy Systems 2
During a prolonged indoor cycling class at moderate intensity, which fuel source does the body preferentially burn after glycogen stores are partially depleted?