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Fuelling Energy Systems and Ergogenic Aids

Fuelling the Energy Systems

  • Carbohydrates:

    • Main Source of Energy:

    • Carbohydrates are the primary energy source for exercise at moderate to high intensity.

    • The metabolism of carbohydrates is more effective than fat metabolism but has limited energy stores.

    • Glycogen Stores:

    • Carbohydrates are stored as glycogen in muscles and liver, capable of fueling approximately two hours of moderate to high intensity exercise.

    • Duration is highly dependent on the individual’s fitness level.

    • If stores are not replenished, athletes experience glycogen depletion leading to what is colloquially known as "hitting the wall."

    • Replenishing Glycogen Stores:

    • Athletes can boost glycogen stores during exercise by consuming high Glycaemic Index (GI) foods, isotonic drinks, and gels.

  • Glycaemic Index (GI):

    • Definition: The glycaemic index measures how quickly carbohydrates release energy (glucose) into the bloodstream.
    • Categories:
    • High GI Foods: Release glucose rapidly.
      • Examples include:
      • White bread
      • White rice
      • Jelly beans
    • Low GI Foods: Release glucose more slowly.
      • Examples include:
      • Fruits
      • Vegetables
    • Application in Sport:
    • Athletes engaged in endurance events should consume a low GI meal 3-4 hours before exercise.
    • During the event, high GI foods can be used to maintain energy levels.

Carbohydrate Loading

  • Definition: Carbohydrate loading, or carb-loading, is the dietary process to increase glycogen storage prior to an endurance event.

  • Stages of Carbohydrate Loading:

    1. Depletion Stage:
    • Athletes reduce muscle glycogen stores by training intensively while simultaneously reducing carbohydrate intake.
    1. Tapering Stage:
    • Training intensity decreases while carbohydrate consumption remains constant to replenish glycogen stores.
    1. Loading Stage:
    • Almost no training, with high carbohydrate intake over 2-3 days to maximize glycogen stores, allowing for supercompensation.

  • Potential Drawbacks:

    • Side effects during carb-loading can include:
    • Lethargy and lack of concentration.
    • Increased cravings and irritability.
    • Increased susceptibly to illness and injury.
    • Recommended intake of carbohydrates: 5-10 grams per kg of body weight in the last 3 days before the event.

Dietary Manipulation

  • Pre-Competition Preparations:

    • Athletes should have adequately carb-loaded days before an event to ensure sufficient glycogen stores prior to competition.
    • In the 2-4 hours before competition:
    • High carbohydrate meals are recommended to top off glycogen stores in the liver.
    • Avoid:
      • Large quantities of food or high-fiber foods which can cause digestive problems.
      • Carbohydrates within an hour before competition to prevent rebound hypoglycemia, which can decrease glycogen stores and lead to fatigue.

  • During Competition:

    • For events lasting more than 45 minutes, athletes should consume small amounts of food/drinks regularly to replenish glycogen. Recommended foods/fluids should be high in carbs and have a high GI.

  • General Advice for Events Over 1 Hour:

    • Keep hydrated and consume small amounts of food/fluids often.
    • Eat 2-4 hours before the event (preferably low GI).
    • Consume high GI foods just before/between competition.

Hydration During Exercise/Competition

  • Importance of Hydration:

    • Essential for reducing the risk of dehydration and optimizing performance, particularly under strenuous activities or in hot environments.

  • Types of Drinks:

    • Hypotonic Drinks:
    • Lower glucose levels than blood (approximately 4-6% glucose), vital during prolonged exercise for rehydration.
    • Isotonic Drinks:
    • Equal glucose levels as blood (around 6-8% glucose), ideal for replenishing fluids and glucose during events lasting longer than 1 hour.
    • Hypertonic Drinks:
    • Contain higher glucose levels (around 10% glucose) but less effective for hydration, increase dehydration risk as they should be diluted with water for optimal absorption.
    • Recommendation:
    • Water is best for hydration purposes when not combined with glucose.

Post-Competition Recovery

  • Post-Exercise Nutritional Focus:
    • The first 1-2 hours post-exercise is critical for replenishing glycogen stores, as the body is highly efficient in converting carbohydrates into glucose.
    • Research indicates the optimal time to consume carbohydrates is within the first 45 minutes post-exercise.
    • Supplementing carbohydrate intake with protein aids glycogen recovery and supports tissue repair from muscle damage.

Legal Ergogenic Aids/Supplementation

  • Definition: Ergogenic aids refer to any methods or devices intended to enhance athletic performance, often categorized into three main types:
    1. Protein:
    • Essential for muscle growth and repair, broken down into amino acids for muscle recovery after exercise. Specifically aids in repairing micro-tears from exercise, leading to muscular hypertrophy.
    • Types of proteins:
      • Whey Protein: Fast absorption, good for immediate post-exercise consumption.
      • Casein Protein: Slower digestion, sustained amino acid release.
    1. Caffeine:
    • Acts as a central nervous system stimulant, enhancing alertness and reaction time while reducing perceived fatigue.
    • Positively impacts high-intensity and strength sports.
    • Some athletes use caffeine tablets pre-exercise to stimulate fatty acid breakdown.
    1. Creatine:
    • Composed of amino acids and is crucial for ATP resynthesis during high-intensity activities.
    • Found naturally in animal foods and supplements, can increase PC levels and improve ATP/PC system efficiency.
    • Suggested that individuals with kidney issues avoid creatine.

Illegal Ergogenic Aids

  • Categories of Illegal Ergogenic Aids and their Effects:
    1. Anabolic Steroids:
    • Synthetic derivatives of testosterone aimed to increase muscle mass and strength.
    • Associated side effects include cardiac, liver, and immune dysfunction, hair loss, and lowered sperm count.
    1. Blood Doping:
    • Involves the removal and later reinfusion of the athlete's red blood cells to enhance oxygen-carrying capacity.
    1. EPO (Erythropoietin):
    • Hormonal agent that increases red blood cell production, improving endurance performance.
    1. Human Growth Hormone (HGH):
    • Used for muscle growth and recovery enhancement.
    1. Beta Blockers:
    • Reduce physiological stress responses, improve focus, and are often banned in competitive settings.
    1. Diuretics and Masking Agents:
    • Move fluid out of the body and may conceal the presence of other banned substances.