Lecture on Central Nervous System and Strength Training

Introduction

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• Focus on the Central Nervous System (CNS) as a key component for strength and performance.

What is the Central Nervous System?

• Comprised of the brain and spinal cord.
• Responsible for thoughts, memories, personality, and movement initiation.
• Works with the Peripheral Nervous System for body control.

Muscle and Fiber Basics

• Muscles are made up of muscle fibers (cells) that contract to move joints.
• Myofilaments within muscle fibers are composed of actin and myosin.
• Muscle fibers contract in a binary manner (contract or do not contract).

Motor Cortex and Neuronal Pathways

• Primary motor cortex contains a body map (motor homunculus) where neurons control different body parts.
• Signals are sent as action potentials to motor neurons, lasting 10-100 milliseconds.
• Continuous contraction requires multiple motor neuron firings.

Motor Units

• Motor units are groups of muscle fibers innervated by a single motor neuron.
• Biceps have 300-800 motor units; motor units vary based on muscle and genetics.
• Signals recruit motor units based on strength, following Henman size principle (smallest to largest recruitment).

Upper vs. Lower Motor Neurons

• Upper motor neurons (in motor cortex) control lower motor neurons (in spine).
• Motor neurons are organized in a homunculus shape, representing control precision.

Signal Volume and Rate Coding

• Volume of signal increased through rate coding (faster signals lead to more firing).
• Untrained individuals recruit 30-75% of motor units; trained individuals 80-95%.

Neural Adaptation and Plasticity

• Neural plasticity allows changes in motor cortex size and shape based on use (e.g., musicians).
• Intramuscular coordination improves with training, allowing better muscle control.

Motor Patterns and Skill Acquisition

• Repetitive movement forms neural connections, aiding skill learning ("neurons that fire together, wire together").
• Motor pathways become more efficient with practice.
• Untrained individuals may show inefficient and tense movements.
• Skilled movements become ingrained and involve multiple brain regions (premotor cortex, basal ganglia, cerebellum).

Training the Central Nervous System

• To improve intramuscular coordination, practice heavy/explosive lifts (80-95% of 1RM).
• Overcoming isometrics (pushing/pulling immovable objects) enhance neural drive and muscle recruitment.
• Skill-based practice (repetition and variation) refines movement patterns (intermuscular coordination).

Movement Variation and Robust Patterns

• Practice on varied surfaces and conditions to develop robust movement patterns.
• Variation enhances ability to adjust to changes and unexpected inputs.

CNS Recovery and Fatigue

• CNS fatigue is acute and recovers quickly, unlike chronic stress effects on autonomic NS.
• Overtraining impacts autonomic NS more than CNS (chronic stress and burnout).
• Recovery involves managing stress and allowing rest.

Stress Resilience and Military Training

• Possible to train resilience to long-term stress.
• Strategies like Bulgarian method and stress inoculation training build mental resilience.

Conclusion

• Strength is a skill; training should involve finesse, not just brute strength.
• Incorporate overcoming isometrics and skill practice for improved performance.
• Consider training programs that enhance overall human performance, not just muscle growth.

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