Muscular Strength and Endurance Ch. 4 (Key Terms)

Nucleus

A cell structure containing DNA and genes that direct the production of proteins; plural, nuclei.

Atrophy

A decrease in size of muscle fibers, usually attributable to inactivity

Concentric Muscle Contraction

A dynamic contraction in which the muscle gets shorter as it contracts; also called a miometric contraction.

Eccentric Muscle Contraction

A dynamic contraction in which the muscle lengthens as it contracts; also called a pilometric contraction.

Set

A group of repetitions followed by a rest period.

Kettlebell

A large iron weight with a connected handle; used for ballistic weight training exercised such as swings and one arm snatches.

Motor Unit

A motor nerve (one that initiates movement) connected to one or more muscle fibers.

Spotter

A person who assists with a weight training exercise done with free weights.

Muscle Fibers

A single muscle cell, usually classified according to strength, speed of contraction, and energy source.

Tendon

A tough band of fibrous tissue that connects a muscle to a bone or other body part and transmits the force exerted by the muscle.

Ligament

A tough band of tissue that connects the ends of bones to other bones or supports organs in one place.

Isokinetic Exercise

A type of dynamic exercise that provides variable resistance to a movement, so the movement occurs at a constant speed no matter how much effort is exerted.

Variable Resistance Exercsie

A type of dynamic exercise that uses a changing load, providing a maximum load at the strongest point in the affected joint's range of motion.

Constant Resistance Exercise

A type of dynamic exercise that uses a constant load throughout a joint's full range of motion.

Hyperplasia

An increase in the number of muscle fibers.

Hypertrophy

An increase in the size of muscle fibers, usually simulated by muscle overload, as occurs during strength training.

Dynamic (Isotonic) Exercise

Exercise causing a muscle contraction and a change in the muscle's length.

Static (Isometric) Exercise

Exercise causing a muscle contraction without a change in the muscle's length or a joint's angle.

Eccentric (Pilometric) Loading

Loading the muscle while it is lengthening; sometimes called negatives.

Speed Loading

Moving a load as rapidly as possible

Myofibrils

Protein structure that make up muscle fibers

Plyometrics

Rapid stretching of a muscle group that is undergoing eccentric stress (that is, the muscle is exerting force while it lengthens), followed by a rapid concentric contraction.

Slow-Twitch Muscle Fibers

Red muscle fibers that a fatigue resistant but have a slow contraction speed and a lower capacity for tension, usually recruited for endurance activities.

Muscle Learning

The improvement in the body's ability to recruit motor units, brought about through strength training.

Repetition Maximum (RM)

The maximum amount of resistance that can be moved a specified number of times. 1-RM is the maximum amount of weight that can be lifted one time; 5-RM is the maximum amount of weight that can be lifted five times.

Repetitions

The number of times an exercise is preformed during one set.

Testosterone

The principal male hormone, responsible for the development of secondary sex characteristics and important in increasing muscle size.

Cartilage

Tough, resilient tissue that acts as a cushion between the bones in a joint.

Fast-Twitch Muscle Fibers

White muscle fibers that contract rapidly and forcefully but fatigue quickly, usually recruited for actions requiring strength, power, or speed.