CDN Sports Nutrition & Performance 4 — Questions and Answers
Question 1: A 16-year-old adolescent football player asks about creatine supplementation. What is the most appropriate recommendation?
- Approve use at adult loading doses of 20g/day
- Discourage use due to insufficient safety data in adolescents (Correct answer)
- Recommend 5g/day as it is proven safe for adolescents
- Suggest combining creatine with anabolic steroids for best results
Correct answer: Discourage use due to insufficient safety data in adolescents
Major sports nutrition organizations discourage creatine supplementation in athletes under 18 due to insufficient long-term safety data, and recommend food-first strategies instead.
Question 2: Which carbohydrate type is most recommended for consumption during exercise lasting longer than 2.5 hours to maximize oxidation rates beyond 60g/hr?
- Fructose alone
- Glucose alone
- Multiple transportable carbohydrates (glucose + fructose) (Correct answer)
- Galactose alone
Correct answer: Multiple transportable carbohydrates (glucose + fructose)
Multiple transportable carbohydrates using both SGLT1 (glucose) and GLUT5 (fructose) transporters allow oxidation rates of 90g/hr+, exceeding the ~60g/hr ceiling achievable with a single carbohydrate.
Question 3: A sports dietitian is calculating energy expenditure for a competitive rower. Which equation is most appropriate for estimating resting metabolic rate in athletes?
- Harris-Benedict equation (original 1919)
- Mifflin-St Jeor equation
- Cunningham equation (using lean body mass) (Correct answer)
- Katch-McArdle equation for sedentary adults
Correct answer: Cunningham equation (using lean body mass)
The Cunningham equation uses lean body mass rather than total weight, making it more accurate for athletes who have higher muscle mass than the general population.
Question 4: A climber training at sea level for a high-altitude expedition asks about beetroot juice. What is the proposed mechanism for its ergogenic benefit?
- Increasing serum testosterone levels
- Enhancing nitric oxide production to improve oxygen delivery (Correct answer)
- Stimulating glycogen synthesis in muscles
- Blocking adenosine receptors to reduce perceived effort
Correct answer: Enhancing nitric oxide production to improve oxygen delivery
Dietary nitrate in beetroot juice is converted to nitric oxide in the body, which vasodilates blood vessels and improves oxygen delivery efficiency, particularly beneficial at altitude.
Question 5: A sports dietitian is advising on caffeine timing for a 10 AM competition. Based on pharmacokinetics, when should the athlete consume caffeine?
- Midnight before competition
- 9:00 AM (60 minutes before) (Correct answer)
- 8:00 AM (120 minutes before)
- During warm-up at 9:45 AM
Correct answer: 9:00 AM (60 minutes before)
Caffeine reaches peak plasma concentration approximately 60 minutes after ingestion, so consuming it 60 minutes before a 10 AM competition (at 9 AM) is optimal for performance benefits.
Question 6: A registered dietitian is assessing energy availability (EA) in a female gymnast. Which formula correctly calculates EA?
- Total calorie intake ÷ body weight in kg
- (Energy intake − exercise energy expenditure) ÷ fat-free mass in kg (Correct answer)
- Basal metabolic rate × activity factor
- Total energy expenditure − resting metabolic rate
Correct answer: (Energy intake − exercise energy expenditure) ÷ fat-free mass in kg
Energy availability is calculated as (energy intake − exercise energy expenditure) divided by fat-free mass (kg), with <30 kcal/kg FFM/day indicating risk for the female athlete triad.
Question 7: Which supplement has demonstrated benefits for decreasing delayed onset muscle soreness (DOMS) and has the strongest current evidence base?
- Glutamine
- HMB (beta-hydroxy beta-methylbutyrate)
- Tart cherry juice (Correct answer)
- Vitamin E
Correct answer: Tart cherry juice
Tart cherry juice, rich in anthocyanins with anti-inflammatory and antioxidant properties, has the strongest evidence for reducing DOMS and accelerating muscle strength recovery.
CDN Sports Nutrition & Performance 4
A 16-year-old adolescent football player asks about creatine supplementation.
What is the most appropriate recommendation?