Energy Systems Lecture by Dr. Jacob Goodin

Introduction

• Presenter: Dr. Jacob Goodin, Professor of Kinesiology
• Institution: Point Loma Nazarene University
• Topic: Energy Systems
• Objective: Understand energy systems for implementing training methods

Key Terms

• Bioenergetics: Flow of energy in biological systems; conversion of macronutrients to ATP
• Catabolism: Breakdown of molecules releasing energy (e.g., ATP to ADP)
• Anabolism: Synthesis of larger molecules from smaller ones using energy
• Exergonic Reactions: Energy-releasing reactions (e.g., ATP breakdown)
• Endergonic Reactions: Reactions requiring energy
• Metabolism: Total catabolic and anabolic reactions
• Adenosine Triphosphate (ATP): Energy currency of the body

ATP and Hydrolysis

• ATP structure: Adenine, ribose, triphosphate group
• Hydrolysis: Breaking phosphate bonds to release energy
• ADP and AMP: Further breakdown of ATP

Three Energy Systems

1. Phosphagen System

   • Provides ATP for short-term, high-intensity exercises
   • Uses creatine kinase to replenish ATP
   • Active at the start of all exercises
   • E.g., sprinting, resistance training

2. Glycolysis

   • Intermediate system
   • Uses glucose (blood or glycogen) to resynthesize ATP
   • Two types: Fast (anaerobic) and Slow (aerobic)
   • Pyruvate fate: Converts to lactate (fast glycolysis) or enters mitochondria (slow glycolysis)

3. Oxidative System

   • Primary ATP source at rest and low-intensity activity
   • Utilizes carbohydrates and fats
   • Links glycolysis products to Krebs cycle and electron transport chain

Phosphagen System

• Fastest system: 0-15 seconds
• Utilizes creatine phosphate
• Limited ATP storage, prioritizes for cellular function
• Law of mass action influences ATP and creatine phosphate balance

Glycolysis

• Anaerobic/Fast Glycolysis: Pyruvate to lactate, rapid ATP resynthesis
  • Lactate dehydrogenase catalyzes this
• Aerobic/Slow Glycolysis: Pyruvate to Krebs cycle, slower but sustained ATP
• Lactate processing in the Cory Cycle: Cleared to liver, converted back to glucose

Oxidative System

• Low-intensity, long-duration energy supply
• Uses fats, carbohydrates, occasionally proteins
• Krebs cycle and electron transport chain activities
• Produces significantly more ATP over time

Energy System Interaction

• Overlap exists between systems based on exercise intensity and duration
• No single system works alone

Practical Implications

• Understanding systems aids in effective training program design
• Intensity and duration dictate energy system engagement

Conclusion

• Overview of energy systems relevant for trainers and coaches
• Future videos to address specific training adaptations (e.g., lactate threshold)

Additional Notes

• Energy system contributions depend on exercise intensity and duration
• Key takeaway: Knowledge of energy systems enhances training specificity