Energy Systems

• The body uses three energy systems to regenerate ATP, based on exercise intensity and duration.
• Understanding these systems and their pathways optimizes athletic performance and recovery.

ATP Yield and Metabolic Pathways

• The Electron Transport Chain (ETC) yields the most ATP, generating 34-36 ATP per glucose molecule in the aerobic system.
• Glycolysis is a common pathway in both anaerobic and aerobic metabolism, breaking down glucose into pyruvate.
• In aerobic conditions, pyruvate enters the Krebs cycle and is processed through the ETC, yielding 38 ATP per glucose.
• In anaerobic conditions, pyruvate turns into lactic acid, producing only 2 ATP per glucose molecule.

ATP Resynthesis During Exercise

• The ATP-PC system provides ATP through creatine phosphate (PCr) breakdown, the fastest ATP resynthesis, depleting within 10 seconds.
• The Lactic Acid System (anaerobic glycolysis) fuels activities for 10-90 seconds, producing 2 ATP per glucose with lactic acid as a byproduct.
• The Aerobic System produces ATP over extended periods through oxidative metabolism, utilizing glucose, glycogen, and fats as fuel.

Cellular Respiration and ATP Breakdown

• Cellular respiration is the controlled energy release from organic compounds to synthesize ATP.
• ATP breakdown releases energy when a phosphate group is removed, converting ATP to ADP, catalyzed by ATPase.
• ATP is resynthesized when ADP gains a phosphate group, facilitated by ATP Synthase.
• Mitochondria are crucial in ATP production, especially in the aerobic system.

Energy System Contributions to Sport and Exercise

• Each energy system predominates in different physical activities.
• The ATP-PC system is used for explosive, short movements like sprinting (100m), weightlifting, and shot put.
• The Lactic Acid System is used for high-intensity efforts lasting 10-90 seconds, including 400m sprints, HIIT workouts, and wrestling.
• The Aerobic System is predominant in long-duration, endurance activities like marathons, cycling, and soccer.

Energy System and Byproducts

• The ATP-PC system's byproduct is creatine and inorganic phosphate, not causing fatigue.
• The Lactic Acid System's byproduct is lactic acid and hydrogen ions (H+), leading to muscle fatigue.
• The Aerobic System's byproducts are water (H2O) and carbon dioxide (CO2), not contributing to fatigue.

Physiological Adaptations in Athletes

• Highly trained athletes adapt to reduce oxygen deficit at exercise onset.
• They show greater lactic acid clearance, improving endurance and recovery.

Training Considerations for Energy System

• ATP-PC System Training involves short, maximum-effort bursts (5-10 seconds) with full recovery (2-3 minutes).
• Lactic Acid System Training involves repeated high-intensity efforts lasting 15-60 seconds, with short recovery (30-90 seconds).
• Aerobic System Training involves long-duration, moderate-intensity exercise to improve mitochondrial efficiency.

Graph Interpretation and Sport-Specific Applications

• The Aerobic System dominates endurance activities, showing gradual ATP production.
• The ATP Store represents limited immediate energy availability.
• The ATP-PC System shows a rapid peak in ATP production but quick depletion.
• The Lactic Acid System shows moderate ATP production with a steady decline as lactic acid accumulates.

Identifying Sports for Each Energy System

• ATPcr System includes sprinting, weightlifting, jumping events.
• Lactic Acid System includes 400m sprints, wrestling, and rowing (mid-distance).
• The Aerobic Respiration System includes long-distance running, cycling, and swimming.

ATP-PC System Characteristics

• Fuel Source: Creatine phosphate (PCr)
• Intensity: High-intensity, explosive efforts
• Duration: 0-10 sec
• Example Activity: 100m sprint, Olympic lifts
• ATP Production: 1 ATP per PCr molecule
• Byproducts: Creatine and inorganic phosphate

Lactic Acid System Characteristics

• Fuel Source: Glycogen/glucose
• Intensity: Moderate to high-intensity efforts
• Duration: 10-90 sec
• Example Activity: 400m sprint, wrestling, HIIT workouts
• ATP Production: 2 ATP per glucose molecule
• Byproducts: Lactic acid and hydrogen ions

Aerobic Respiration System Characteristics

• Fuel Source: Glucose, glycogen, and fats
• Intensity: Low to moderate intensity
• Duration: Long-duration activities (90 sec+)
• Example Activity: Marathon running, cycling
• ATP Production: 38 ATP per glucose molecule
• Byproducts: Water (H2O) and carbon dioxide (CO2)

Explore the ATP-PC, lactic acid, and aerobic systems. Understand energy production, fuel sources, and durations. Investigate ATP resynthesis and metabolic processes.