Physiology of Resistance Training

Flashcards covering key vocabulary and concepts from the lecture on the physiology of resistance training.

Overload Principle

Training effect occurs when a physiological system is exercised at a level beyond which it is normally accustomed.

Variables include: intensity, frequency, and duration

Specificity Principle

Training is specific to:

• the fiber type recruited

• energy system involved

• type of contraction.

Reversibility

Gains are lost when overload is removed.

Hypertrophy

Increase in muscle size due to an increase in size of existing muscle fibers.

Atrophy

Decrease in muscle size and strength, often due to disuse or aging.

Sarcopenia

Loss of muscle mass and strength associated with aging.

1 repetition maximum (1-RM)

The maximum force that a muscle group can generate in one complete movement.

Neural Adaptations

Adaptations in the nervous system that lead to increased muscular strength, especially in the early stages of strength training.

Cross-education

Training of one limb results in increases of strength in the untrained limb.

Satellite Cells

Stem cells that activate during resistance training to increase the number of myonuclei in muscle fibers.

mTOR (mechanistic target of rapamycin)

A protein kinase that is a key factor in accelerating protein synthesis following resistance training.

Hyperplasia

An increase in the number of muscle fibers, though its occurrence in humans is still unclear.

Muscle Protein Synthesis

The process by which cells build proteins, which can be stimulated by resistance training.

Detraining Effects

The phenomenon where muscles can atrophy when training stops, but the decline is slower than in endurance training.

Disinhibition

Reduction in neurologic inhibitory signals, allowing for greater activation of motor units during contraction.

Type I fibers

Slow twitch muscle fibers known for greater endurance.

Type II fibers

Fast twitch muscle fibers known for greater force production.

Mechanoreceptor

Sensory receptors that respond to mechanical pressure or distortion, playing a role in muscle contraction responses.

Protein Synthesis Rate

The rate at which muscle protein content changes, influenced by resistance training.

Muscle Fiber Types

Categorized as Type I (slow twitch), Type IIa (fast oxidative), and Type IIx (fast glycolytic), each with different performance characteristics.

Autogenic Inhibition

The nervous system's mechanism to inhibit muscle contraction via Golgi tendon organs.

Myonuclei

Nuclei within muscle fibers that are essential for muscle repair and growth.

Hierarchy of skeletal muscle:

1. Muscle

2. Fascicles

3. Myocytes

4. Contractile Proteins: actin and myosin

5. Arrangement in functional units: sarcomeres

6. Muscle cell membrane: sarcolemma

Excitation-Contraction

• Action potential from CNS travels down alpha motor neuron

• Depolarization of sarcolemma leads to calcium ion release from sarcoplasmic reticulum

• Ca2+ release triggers cross-bridge formation and muscle contraction

Strength gains during the first 8 weeks of training are largely due to ______ ______ ________

Nervous system adaptations

Evidence that neural adaptations occur:

• Muscular strength increases in first two weeks of training without increase in muscle fiber size

• Phenomenon of “cross education,” - training one limb results in increases of strength in untrained limb