NASM-MMACS key terms

The study of human movement, including how muscles, bones, and joints work together to produce motion. Candidates use it to select exercises and analyze faulty movement patterns.

The application of physics principles such as force, torque, and leverage to human movement. It explains why exercise setup and body positioning change muscle demand and joint stress.

The motion of joint surfaces relative to one another, described as roll, glide, and spin. Restricted glide can limit osteokinematic motion, so trainers screen range of motion before loading a joint.

Visible movement of bones at a joint, measured in degrees, such as flexion, extension, abduction, and rotation. It is what a goniometer or movement screen records during assessment.

The perpendicular distance between a joint's axis of rotation and the line of force acting on it. Longer moment arms increase torque, which is why exercise lever position changes difficulty.

A rotational force equal to force multiplied by moment arm. Trainers manipulate load and lever length to match torque demands to a client's capacity and training goal.

The principle that a muscle produces the most active tension at near-resting length and less at very short or very long lengths. It informs exercise range-of-motion choices and stretching decisions.

Reduced force output when a muscle is shortened so much that its actin and myosin overlap excessively. It explains weakness at end-range positions such as full hip flexion during a hamstring exercise.

Range-of-motion limitation caused when a stretched muscle or its connective tissue reaches maximum length and resists further elongation. It can restrict a joint before the target muscle is fully trained.

The relationship showing that a muscle produces more force during slower concentric actions and less during faster ones, while eccentric actions can produce the most force. It guides tempo and loading choices.

A muscle action in which the muscle shortens while producing force, such as rising from a squat. It is a primary stimulus for strength and hypertrophy when loaded progressively.

A muscle action in which the muscle lengthens under tension, such as lowering into a squat. Eccentric training builds strength and tissue tolerance but causes more delayed soreness.

A muscle action in which tension develops without a change in muscle length or joint angle. It is used for stabilization training and for early rehabilitation when movement is painful.

A single motor neuron and all the muscle fibers it innervates. Recruitment order and firing rate determine how much force a muscle can generate.

The rule that motor units are recruited from smallest to largest as force demand rises. It supports using heavier or faster loads when the goal is recruiting high-threshold units.

Increased force production achieved by raising the firing frequency of already recruited motor units. It explains strength gains that occur without visible muscle growth.

A sequence of eccentric loading, brief amortization, and concentric unloading that lets elastic tissue and reflexes add force. It underlies plyometric exercise and jump performance.

Elastic structures, mainly tendons, that store energy when stretched and release it during shortening. Their contribution explains the added force in a rapid countermovement jump.

Specific Adaptation to Imposed Demands: the body adapts specifically to the stress placed on it. It justifies matching exercise selection, velocity, and load to the client's goal.

Systematically increasing training stress over time by adding load, volume, density, or complexity. It is required for continued adaptation and must be balanced against recovery capacity.

A measure of total work calculated as sets multiplied by repetitions multiplied by load lifted. Trainers track it to progress or reduce training stress across a mesocycle.

The manipulable training components: repetition range, sets, intensity, tempo, rest interval, exercise selection, and frequency. Program design is largely the deliberate arrangement of these variables.

The number of training sessions per week, or per muscle group, within a given period. It is adjusted for recovery, experience level, and total weekly volume.

Planned variation of training variables across time, often organized into macrocycles, mesocycles, and microcycles. It manages fatigue, prevents plateaus, and peaks performance for a target date.

A training block typically lasting several weeks to a few months that pursues a specific goal, such as hypertrophy or strength. It sits between the macrocycle and the microcycle.

The shortest planned training unit, usually one week, detailing sessions, loads, and rest days. It operationalizes the goals of the surrounding mesocycle.

A planned reduction in training stress, usually volume or intensity, to restore recovery and performance. It is often placed at the end of a demanding mesocycle.

A subjective rating of effort during exercise, commonly on a 0-to-10 scale. It helps regulate intensity when percentages of one-repetition maximum are impractical or unsafe.

The estimated number of additional repetitions a client could complete before technical failure. It is used to autoregulate load and keep training near a target proximity to failure.

The heaviest load a client can lift once with acceptable technique. It anchors intensity prescriptions, and submaximal estimates are often safer for general clients.

A standing assessment in which the client squats with arms overhead while a trainer observes from front and side views. It reveals mobility and stability compensations before program design.

Observation of a client performing a movement task to identify altered alignment and control under load. It complements static posture and range-of-motion checks.

An altered movement strategy in which one segment moves excessively or insufficiently to accomplish a task. Trainers interpret compensations as clues about mobility or stability deficits.

Measurement of joint range of motion in degrees using a goniometer. It provides objective baseline data for mobility restrictions and progress tracking.

The extent of movement available at a joint, whether produced actively by the client or passively by the trainer. It sets boundaries for exercise selection and stretching.

The ability of a muscle or muscle group to sustain repeated contractions over time. It is trained with moderate loads, higher repetitions, and shorter rest intervals.

Rapid stretch-shortening movements such as jumps or bounds that train explosive force production. Progression requires adequate strength, landing control, and a suitable surface.

Assisting a lifter during an exercise to prevent injury or complete a failed repetition. It requires agreed signals, correct positioning, and knowledge of which exercises can be safely spotted.

The execution of an exercise with alignment, control, and appropriate joint positions for the intended stimulus. Poor technique changes muscle demand and raises injury risk.