Lec 19

Concentric contractions

Muscle contractions where the muscle is actively shortening.

Eccentric contractions

Muscle contractions where the muscle is actively lengthening.

Isometric contractions

Muscle contractions where the muscle is actively held at a fixed length.

Passive stretch

Muscle lengthens without activation; very little energy is required.

Low Level Tension

Muscles maintain posture at rest.

Proprioception

The ability of the CNS to sense the relative position of the body.

Atrophy

The shrinkage in diameter of muscle fibers due to disuse.

Hypertrophy

The increase in muscle size resulting from overload training.

Hyperplasia

An increase in the number of muscle cells, which is rare in adults.

Fast twitch, glycolytic muscle fibers

Muscle fibers that produce lots of force quickly but fatigue easily.

Slow twitch, oxidative muscle fibers

Muscle fibers that produce less force, sustain contractions longer, and fatigue slowly.

Fast twitch, oxidative muscle fibers

Muscle fibers with moderate force production, relatively aerobic, and moderate fatigue resistance.

Motor end plates

Axon terminal-muscle cell interface that can be repaired after injury or pathology.

Recruitment of motor units

The process of activating sufficient motor units to control force production.

Stimulus frequency

The number of stimulations per second that determines the force of contraction.

Greg Valentino

An individual known for using techniques to minimize catabolic effects and maximize anabolic actions.

Anabolic Steroids

Enhance muscle growth by minimizing catabolism.

Myostatin gene

A gene that normally limits muscle growth; mutations in this gene can lead to hyperplasia.

Heritability of muscle fiber type

The extent to which muscle fiber types are inherited, greater than 50%.

Tai Chi

A practice that utilizes slow movements to enhance proprioceptive abilities in mind/body integration.

Cortisol

Hormone that promotes muscle catabolism.

IGF/Human growth hormone

Stimulates muscle hyperplasia in adults.