Skeletal Muscle Adaptation & Fatigue

A set of vocabulary flashcards covering key definitions for skeletal muscle adaptation, neural changes, and fatigue mechanisms based on the lecture notes.

Muscle adaptation

Structural and functional changes in muscle in response to exercise training.

Hypertrophy

An increase in muscle fibre size due to increased protein synthesis.

Atrophy

A decrease in muscle size caused by reduced protein synthesis or increased protein breakdown.

Myofibrillar hypertrophy

An increase in the size and number of myofibrils within a muscle fibre.

Satellite cells

Muscle stem cells involved in muscle repair, growth and regeneration.

Protein synthesis

The process of building new proteins within cells.

MTOR

A signalling protein that regulates protein synthesis and muscle growth.

IGF-1 (Insulin-like Growth Factor-1)

A growth factor that stimulates muscle growth and activates the mTOR pathway.

Neural adaptation

Improvements in strength due to changes in nervous system function rather than muscle size.

Motor unit recruitment

The activation of additional motor units to produce greater force.

Rate coding

An increase in motor neuron firing frequency to produce greater muscle force.

Mitochondrial biogenesis

The formation of new mitochondria within muscle cells.

PGC-1a

The key regulator of mitochondrial biogenesis following endurance training.

Capillarisation

An increase in the number of capillaries supplying skeletal muscle.

Myoglobin

An oxygen-binding protein found in skeletal muscle.

Oxidative enzymes

Enzymes involved in aerobic energy production within mitochondria.

Muscle fatigue

A reversible reduction in the ability of a muscle to produce force or power.

Inorganic phosphate (Pi)

A by-product of ATP breakdown that contributes to muscle fatigue.

Glycogen depletion

A reduction in muscle glycogen stores that limits prolonged exercise performance.

DOMS (Delayed Onset Muscle Soreness)

Muscle soreness occurring $24-72$ hours after unaccustomed exercise, especially eccentric exercise.

Eccentric contraction

A muscle contraction in which the muscle lengthens while producing force.

Golgi tendon organ (GTO)

A sensory receptor that detects muscle tension and helps prevent excessive force.

Autogenic inhibition

A protective reflex in which activation of the GTO reduces muscle contraction.