Nutrition D.4: Nutritional Strategies Flashcards
D.4.1. State the approximate glycogen content of specific skeletal muscle fibre types
- Slow Twitch (Type I) – Low glycogen content
- Fast Twitch (Type IIa) – Medium-glycogen content
- Fast Twitch (Type IIb) – High-glycogen content
Type IIa and Type IIb are high in glycogen content depending on training status
D.4.2. Describe, with reference to exercise intensity, typical athletic activities requiring high rates of muscle glycogen utilization
High intensity:
- Anaerobic metabolism
- Uses fast twitch fibers
- Demand high rates of glycogen
Low intensity:
- Type 1 (slow twitch) fibers will be used
- Resynthesis of ATP will be aerobic/Krebs cycle
D.4.3. Discuss the pattern of muscle glycogen use in skeletal muscle fiber types during exercise of various intensities
- Glycogen fuels ATP production in aerobic and anaerobic activities
- Low-intensity exercise = slow-twitch fibers → low glycolysis
- High-intensity exercise = fast-twitch fibers → more glycogen
- Higher intensity = more glycogen used (75% VO₂max, 85% max HR)
D.4.4. Define the term Glycemic Index (GI)
GI ranks carbs by their immediate impact on blood glucose compared to pure glucose.
D.4.5. List foods with low and high glycemic indexes
D.4.6. Explain the relevance of GI with regard to carbohydrate consumption by athletes pre- and post-competition
- Before exercise = Low GI → slow energy release, stable blood sugar, more fat use
- During exercise = High GI → quick digestion, fast energy
- After exericse = High Gi → boosts muscle glycogen recovery
- Other meals: mostly moderate or low GI
- Low GI diets help athletes maintain low body fat
D.4.7. Discuss the interaction of carbohydrate loading and training programme modification prior to competition
- A tactic used by athletes to maximize glycogen for high-intensity endurance events
- Low glycogen leads to fatigue and reduced performance
Who needs carb loading?
- Athletes who participate in high-intensity endurance sport or training session
Rule of thumb:
- Any sports events in which aerobic system is used > 25% requires carb loading
- Recommended in endurance sport even lasting 90+ minutes
Why Carbohydrate Loading?
- Increases glycogen stores up to 300%
- Provide a sustained source of energy during training or competition
Steps to follow for carb loading (important !!)
- Reduce intensity and duration of training by ~50%
- Increase daily intake of carbs to 8-10g/kg (70-80% of total kcal should come from complex carbs)
- Carbs consumed GI should be below 55
- Sweet potatoes, brown rice, spaghetti, and quinoa are preferred choices
D.4.8. State the reasons for adding sodium and carbohydrate to water for the endurance athlete (important !!)
- CHO in sports drinks delay muscle glycogen depletion and boost performance
- CHO intake produce anti-fatigue effect
- Replenish on electrolytes
- Electrolytes enhance fluid absorption
D.4.9. Discuss the use of nutritional ergogenic aids in sports
What is an ergogenic aid?
Anything that gives you a mental or physical edge while exercising or competing.
E.g. caffeine and sports drinks to illegal substances.
Use of ergogenic aids in sports
Designed for easy intake of fluids/macronutrients during exercise when regular food isn’t practical.
E.g. Sports drinks, bars and gel
Compounds and supplements as ergogenic aids
Caffeine:
- Increase exercise performance at a range of exercise intensities
- Anxiety, insomnia, mild diuretic, weakly addictive
Creatine:
- Benefit exercise that relies on the PCr energy system
- Increase in body mass
Bicarbonate:
- Increase performance during high-intensity exercise lasting 1-7 minutes
- Can cause gastrointestinal upset
D.4.10. State the daily recommended intake of protein for adult male and female non-athlete
0.8g/kg of body weight
D.4.11. LIST SOURCES OF PROTEIN FOR VEGETARIAN ATHLETES
D.4.11. LIST SOURCES OF PROTEIN FOR NON-VEGETARIAN ATHLETES
D.4.12. Discuss the significance of strength and endurance training on the recommended protein intake for male and female athletes
- Athletes need more protein than sedentary individuals
- Endurance athletes need 1.2–1.4 g/kg/day
- Strength athletes need 1.2–1.7 g/kg/day for muscle repair and growth
Recommended protein intake:
- Strength training athletes > Endurance athletes > sedentary individual
D.4.13. Outline the possible harmful effects of excessive protein intake
- High cholesterol and higher risk of cardiovascular disease
- Increased cancer risk
- Kidney disease and kidney stones
- Weight gain
- Constipation or diarrhea
