CNS Sports Nutrition & Exercise Physiology 1 — Questions and Answers
Question 1: Which energy system provides the primary fuel source during a 400-meter sprint lasting approximately 45–60 seconds?
- Oxidative phosphorylation
- Phosphocreatine (ATP-PCr) system
- Glycolytic system (Correct answer)
- Beta-oxidation
Correct answer: Glycolytic system
The glycolytic system (anaerobic glycolysis) is the predominant energy pathway for high-intensity efforts lasting roughly 30–120 seconds, such as a 400-meter sprint.
Question 2: Current evidence-based protein recommendations for strength-trained athletes seeking muscle hypertrophy suggest a daily intake of approximately:
- 0.8 g/kg body weight
- 1.2–1.4 g/kg body weight
- 1.6–2.2 g/kg body weight (Correct answer)
- 3.0–3.5 g/kg body weight
Correct answer: 1.6–2.2 g/kg body weight
Research consistently supports 1.6–2.2 g/kg/day as the effective range for maximizing muscle protein synthesis in resistance-trained individuals.
Question 3: A competitive cyclist plans to compete in a 3-hour road race. Which carbohydrate strategy best supports endurance performance during the event?
- Consume 20–30 g carbohydrate per hour from a single source
- Consume 60–90 g carbohydrate per hour from multiple transportable carbohydrate sources (Correct answer)
- Rely exclusively on fat oxidation and avoid carbohydrates during exercise
- Consume 120 g carbohydrate per hour to fully saturate absorption
Correct answer: Consume 60–90 g carbohydrate per hour from multiple transportable carbohydrate sources
Multiple transportable carbohydrates (e.g., glucose + fructose) can be oxidized at up to 90 g/hr, sparing glycogen and sustaining high-intensity output during prolonged endurance events.
Question 4: The American College of Sports Medicine recommends athletes drink enough fluid during exercise to prevent body weight loss exceeding:
- 0.5% of body weight
- 2% of body weight (Correct answer)
- 5% of body weight
- No specific threshold exists
Correct answer: 2% of body weight
Dehydration exceeding 2% of body weight measurably impairs aerobic performance and cognitive function, making this the commonly cited threshold for significant performance decrements.
Question 5: Which of the following female athletes is at GREATEST risk for developing iron-deficiency anemia?
- A recreational golfer training 3 hours per week
- An elite distance runner training 80 miles per week on hard surfaces (Correct answer)
- A competitive swimmer training 10 hours per week
- A collegiate field hockey player training 6 hours per week
Correct answer: An elite distance runner training 80 miles per week on hard surfaces
Elite distance runners face compounding iron-loss factors: high menstrual losses, foot-strike hemolysis, GI blood loss, hepcidin elevation post-exercise, and heavy sweat losses.
Question 6: Creatine monohydrate is most well-supported by evidence for enhancing performance in which type of activity?
- Marathon running
- Repeated short bouts of high-intensity exercise (e.g., sprint intervals) (Correct answer)
- Steady-state aerobic cycling at 60% VO2max
- Flexibility and stretching protocols
Correct answer: Repeated short bouts of high-intensity exercise (e.g., sprint intervals)
Creatine supplementation increases phosphocreatine stores, supporting rapid ATP resynthesis and improving performance in repeated short bouts of maximal or near-maximal effort.
Question 7: For optimal muscle glycogen resynthesis after exhaustive endurance exercise, what is the recommended carbohydrate intake during the first 4 hours of recovery?
- 0.5 g/kg/hr
- 1.0–1.2 g/kg/hr (Correct answer)
- 2.5 g/kg/hr
- Carbohydrate timing does not affect resynthesis rate
Correct answer: 1.0–1.2 g/kg/hr
Consuming approximately 1.0–1.2 g of carbohydrate per kg body weight per hour during the first 4 hours post-exercise maximizes glycogen synthase activity and restores muscle glycogen rapidly.
CNS Sports Nutrition & Exercise Physiology 1
Which energy system provides the primary fuel source during a 400-meter sprint lasting approximately 45–60 seconds?