Notes

Repetition one complete movement, going through the full range of motion and back
RM (Repetition Maximum) the maximum resistance you can overcome in one attempt. In weight lifting, for example, it is the maximum amount of weight you can lift; if more weight were added you could not complete the lift. This measurement is often used in setting up a weight-training program
Set one series of repetitions done without rest, but followed by a rest period
agonist a muscle in a state of contraction, opposed by the action of another muscle (its antagonist)
anabolic steroids synthetic male hormones taken to build muscle mass and strength
antagonist a muscle that opposes the action of another muscle at the same joint; for example, at the elbow: biceps / triceps; at the knee: hamstrings / quadriceps
antagonistic muscle groups muscles or muscle groups that move the same joint in opposite directions; that is, they work opposite of each other
atrophy when a muscle becomes smaller and weaker because of disuse
auxiliary muscles the muscles that are only partially involved in causing a particular movement; in terms of strength training, these are not the muscles you intend to work, but they are involved to some degree and, thus, gain some partial benefit from the training
concentric muscle contraction muscle activation in which the muscle shortens
constant speed the speed of the movement stays the same throughout the exercise
dynamic (isotonic) muscle contraction the muscle is activated (contracted) causing the muscle to shorten; in some cases outside forces acting on the joint cause the muscle to elongate, or lengthen, instead of shortening
eccentric muscle contraction muscle activation during which an outside force elongates (lengthens) the muscle
fast-twitch fibers muscle fibers (white fibers) that generate speed and power
hyperplasia an increase in the number of muscle cells
hypertrophy when a muscle becomes larger and stronger in response to overloading
isokinetic exercise the resistance, or overload, to the muscle remains constant through the full range of motion; the muscles, then, must maintain a constant level of exertion throughout the exercise; there are two forms of isokinetic exercise, variable resistance and constant speed
isometric exercise the muscle contracts when pressed against an object that does not move
isotonic exercise working the muscles through a range of movement using resistance such as weights and exercise machines
ligaments a band of tissues that connects a bone to a bone; ligaments function to hold bones together at the joint
motor neuron a nerve going from the brain or central nervous system (CNS) to a motor unit in a skeletal muscle
motor unit a group of muscle fibers that are fired by a single motor-neuron signal
muscle fiber a single muscle cell, usually classified according to strength, speed of contraction and energy source
periodization periodically varying the type and amount of exercise; periodization forces your body to use muscles differently, and to use different muscles
plyometric exercise a form of exercise that involves stretching a particular muscle and then quickly trying to contract it
power force that is exerted rapidly (Power = Force x Velocity); it is a combination of speed and strength
primary muscles the muscles and muscle groups that are most involved in causing a particular movement; in terms of strength training, these are the muscles that you intend to work in a specific exercise
recruitment the simultaneous activation of several motor neurons, causing their motor units to contract at the same time, creating a stronger contraction and generating more force
repetitions the number of times an exercise is done during one set
SAID Principle Specific Adaptation to Imposed Demand is a principle of overload stating that the muscle will adapt to the demand (resistance) imposed on it, and that the response (growth) will be specifically aligned to overcoming the imposed demand
slow-twitch fibers muscle fibers (red fibers) that provide muscular endurance
static (isometric) muscle contraction the muscle is activated (contracted) but the muscle stays the same length, neither lengthening nor shortening (no movement takes place)
tendons a band of fibrous tissue that connects a muscle to a bone
variable resistance the actual resistance to the muscle remains the same through the full range of motion