Energy Production and Systems

  • Energy Systems Overview

    • 3 energy systems work together for ATP production:
    • ATP-PC System
    • Anaerobic Glycolysis
    • Aerobic System

  • Key Knowledge

    • Understanding of fuel types for ATP resynthesis at various intensity levels
    • Characteristics of energy systems:
    • Rate of ATP production
    • Yield
    • Fatigue factors
    • Recovery rates (active vs passive)

  • Fuels for Energy

    • Chemical Fuels:
    • ATP, Phosphocreatine (PC), Carbohydrates (CHO), Fats, Proteins.
    • Food Fuels:
    • Examples include bread, rice (CHO), oils, meats (Fats), etc.
    • RDI:
    • CHO: 55-65%, Fats: 25-30%, Proteins: 10-15%.

  • Chemical Fuels Breakdown:

    • ATP Production:
    • ATP is formed by breaking down foods and stored as:
      • Glycogen in muscles
      • Free Fatty Acids (FFA) in the blood
      • Amino Acids in muscles

  • Energy Systems Functionality

    • ATP-PC System:
    • Fastest, used for short, high-intensity activities (0-10 sec).
    • Anaerobic Glycolysis:
    • Produces ATP without O2, mainly from CHO. Yields 2-3 ATP per glucose.
    • Aerobic System:
    • Slowest but high yield (36-441 ATP), uses O2 primarily and can utilize CHO and fats.

  • Energy Demand

    • Determined by intensity of activity and total duration
    • Generally, higher intensity requires anaerobic systems initially, but as duration increases, aerobic systems become predominant.

  • Fatigue Factors

    • Muscle fatigue caused by:
    • Fuel depletion
    • Accumulation of metabolic by-products (like H+ and lactate)

  • Recovery Mechanisms

    • Importance of active recovery for higher O2 levels aiding fuel replenishment and waste removal.
    • PC restoration takes longer during passive recovery.

  • Interplay of Energy Systems

    • All systems contribute jointly but one system predominates based on the exercise context, changing dynamically throughout an activity.
    • Example: Sprinting predominantly uses ATP-PC and anaerobic glycolysis, while long-distance running shifts toward aerobic contributions over time.

  • Nutrition for Performance

    • Knowledge of glycaemic index helpful for strategizing food intake before, during, and post-exercise.