chapter 9

Vocabulary terms covering muscle structure, architecture, contractile components, and the relationships between force, length, and velocity as presented in Week 13 of Muscle Mechanics.

Epimysium

The connective tissue layer that covers the entire muscle.

Perimysium

The connective tissue covering a fascicle, which is a bundle of muscle fibers.

Endomysium

The connective tissue layer surrounding individual muscle fibers.

Sarcomere

The active contractile element of the myofibril, consisting of actin and myosin filaments.

Sliding Filament Theory

A theory describing how myosin cross-bridges pull on actin to shorten the sarcomere, using ATP as an energy source.

Agonist

The muscle that is primarily responsible for creating a specific joint movement.

Antagonist

The muscle that creates motion against the agonist motion.

Concentric Action

A muscle action where tension is greater than resistance, causing the muscle to shorten.

Eccentric Action

A muscle action where the tension produced is less than the resistance, resulting in a passive lengthening of the muscle.

Isometric Action

A static muscle action where the tension produced is equal to the resistance, resulting in no change in muscle length.

Parallel Architecture

Muscle fiber arrangement characterized by fibers running parallel to the tendon, offering greater Range of Motion (ROM) but less tension.

Pennate Architecture

Muscle fiber arrangement where fibers are attached at an angle to the tendon, resulting in less ROM but greater tension and cross-sectional area.

Contractile Component (CC)

The active element of the Hill Model, represented by the sarcomere, which is the only component where force can be controlled.

Parallel Elastic Component (PEC)

A passive element of the Hill Model consisting of the connective tissues (epimysium, perimysium, endomysium) surrounding sarcomeres.

Series Elastic Component (SEC)

A passive element of the Hill Model represented by the tendon.

Force-Velocity Relationship

The mechanical principle stating that maximal force output depends on the velocity of muscle action, where $F_{eccentric} > F_{isometric} > F_{concentric}$.

Strength Training

Training involving high loads and few repetitions that shifts the force-velocity curve upward.

Speed Training

Training characterized by light loads and more repetitions to increase the velocity of movement.

Muscle Power

The product of force and velocity ($P = F \times V$), with optimal resistance for power training usually occurring at approximately $1/3 \text{ RM}$.

Resting Length ($L_0$)

The optimal length of a sarcomere where active force generation is at its maximum.

Hysteresis

Properties of biological tissue related to energy storage and reutilization in passive components during stretching and force production.