Energy Systems in Exercise (Movement System)

Overview

• Discussing 4-5 energy systems involved in exercise:
  • ATP-PC Cycle
  • Aerobic/Anaerobic Glycolysis
  • Krebs Cycle
  • Oxidative Phosphorylation
  • Metabolism of Fats
• Focus: Utilization of these systems during different types of exercise and training adaptations.

Energy Systems

ATP-PC System

• Fastest ATP production rate
• Immediate energy within 1-2 seconds by splitting phosphocreatine
• Depletes fastest; can’t be used for long durations
• Example: Shot put (quick effort)
• Video available on ATP-PC system (linked in the description)

Fast Glycolysis (Anaerobic Glycolysis)

• Net ATP: 2 per glucose molecule
• Converts glucose → pyruvate → lactate
• Produces 2 ATP, unlike ATP-PC’s 1 ATP
• Takes a bit longer than ATP-PC
• Example exercises: High-intensity efforts lasting 10-15 seconds (e.g., 100-meter sprint, pole vault, hockey breakaway)
• Mixed contribution from ATP-PC, Fast Glycolysis, and Aerobic systems

Aerobic Glycolysis (Slow Glycolysis)

• Moderate ATP production rate and capacity
• Glucose → pyruvate → Krebs Cycle/Oxidative Phosphorylation
• Full oxidation of glucose provides 38 ATP
• Primary system in endurance running (800 meters to multi-mile distances)
• Example: Mostly used in distance events, playing a smaller role in shorter sprints

Oxidation of Carbohydrates

• Involves Krebs Cycle and Oxidative Phosphorylation
• Full oxidation of glucose: 38 net ATP
• Requires oxygen; slower rate but higher yield
• Primary system for most distance events (e.g., marathons, long runs)
• Mixed with fat/protein oxidation in ultra-endurance events

Oxidation of Fats

• Lipolysis and Beta Oxidation: Conversion of triglycerides into acetyl-CoA
• High ATP yield (200+ ATP) but slow and oxygen-dependent
• Primary system in very long-duration activities (e.g., marathons, ultramarathons)
• Mixed contribution in moderate endurance events (e.g., 5k, 10k)

Practical Application

• Different sports/exercises rely on different energy systems
• All systems can be secondary contributors depending on the intensity and duration
• Training adaptations vary based on which systems are predominantly used

Additional Resources

• Detailed videos on each energy system available in the description
• Join discussions on energy systems in the Strength Conditioning Study Group on Facebook

Conclusion

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• Leave questions in the comments or join the study group for further discussion