NCAA CPL Human Performance key terms

Two muscles or muscle groups that produce opposite joint actions, such as the biceps brachii and triceps brachii at the elbow. When one contracts to create movement, the other lengthens and controls the motion.

Explanation of muscle contraction in which actin filaments slide past myosin filaments, shortening sarcomeres. Myosin cross-bridges attach, pivot, and detach in repeated cycles powered by ATP, pulling the Z-lines closer together.

A single alpha motor neuron and all the muscle fibers it innervates. All fibers in the unit contract together, and units are recruited in order of increasing size as force demand rises.

The rule that motor units are recruited from smallest to largest as force requirements increase. Low-threshold units handle fine, low-force tasks, while high-threshold units join in for powerful or fast contractions.

Increasing force output by raising the frequency of action potentials sent to already recruited motor units. Higher firing rates cause fused tetanic contractions and greater tension than recruitment alone.

The principle that a muscle produces the most active tension at an optimal resting length, where actin–myosin overlap is ideal. Too much stretch or shortening reduces cross-bridge formation and force.

The continuum from concentric (shortening) through isometric (static) to eccentric (lengthening) actions. Eccentric actions can generate the greatest force and often cause more delayed muscle soreness.

The immediate energy pathway that regenerates ATP from phosphocreatine via creatine kinase. It supplies energy for roughly the first ten seconds of maximal effort and requires no oxygen.

Breakdown of glucose or glycogen to lactate without oxygen, yielding about two to three ATP per unit of substrate. It dominates during high-intensity efforts lasting roughly ten seconds to two minutes.

ATP production in the mitochondria using oxygen, the electron transport chain, and the Krebs cycle. It is slower to activate but yields the most ATP and supports sustained submaximal activity.

The highest rate at which the body can consume oxygen during intense exercise, expressed in milliliters per kilogram per minute. It reflects cardiorespiratory fitness and sets the ceiling for aerobic power.

The exercise intensity at which blood lactate begins to rise faster than it can be cleared. It marks the transition toward greater anaerobic contribution and is a strong predictor of endurance performance.

Elevated oxygen uptake above resting levels after exercise ends. It supports replenishment of phosphocreatine, lactate clearance, and elevated body temperature, and is larger after higher-intensity or longer sessions.

The inverse relationship between the load a muscle moves and the speed of shortening. Heavy loads move slowly with high force; light loads move quickly with lower force, and power peaks at intermediate values.

The perpendicular distance from a joint's axis of rotation to the line of action of a force. A longer moment arm increases the torque produced by that force for the same applied load.

The rotational effect of a force about an axis, calculated as force multiplied by moment arm. Joint torque determines how hard a muscle must pull to move or hold a limb against resistance.

Rigid segments that rotate about a fulcrum when force is applied. Human limbs act as third-class levers, which favor speed and range of motion but require larger muscle forces than the load.

The point where the body's total weight is considered concentrated. It shifts with limb position and equipment, and it must remain over the base of support for stable standing balance.

The area beneath and between the points of contact with the ground. A wider, longer base, such as a split stance, increases stability and makes balance harder to disturb.

The resistance of a body to disruption of equilibrium. It increases with a larger base of support, a lower center of gravity, greater mass, and better friction between the feet and the surface.

A stored set of movement commands that can be executed without continuous feedback. It explains how skilled performers produce fast, coordinated actions and adapt them to changing conditions.

Open skills are performed in unpredictable, changing environments and require adaptation, such as dribbling against defenders. Closed skills occur in stable, predictable settings, such as a free throw.

A three-stage model of skill learning: cognitive, where learners think through the task; associative, where errors shrink with practice; and autonomous, where execution becomes automatic and attention is freed.

Information about performance used to improve learning. Intrinsic feedback comes from the performer's senses, while extrinsic or augmented feedback is supplied by a coach, video, or timing device.

Augmented feedback about the outcome of a movement, such as whether a shot went in or how far a jump traveled. It is especially valuable early in learning when intrinsic information is limited.

Practicing a skill under changing conditions, such as varying distances or speeds. It improves retention and transfer by forcing learners to adapt rather than repeat one fixed movement pattern.

Reflex relaxation of the antagonist muscle while the agonist contracts. It smooths joint motion, and tight or overactive antagonists can restrict range of motion and alter movement patterns.

A ranking of carbohydrate foods by how quickly they raise blood glucose compared with a reference food. Lower-index foods release glucose slowly, while higher-index foods suit rapid pre- or post-exercise fueling.

A strategy of increasing carbohydrate intake and tapering training before endurance events to maximize muscle glycogen stores. It can extend time to exhaustion in prolonged continuous activity.

The cellular process of building new proteins from amino acids. Resistance exercise and adequate protein intake, spread across the day, increase muscle protein synthesis and support training adaptation.

Maintaining adequate body water before, during, and after activity. Even mild dehydration impairs thermoregulation and performance, and sweat losses vary widely between individuals and conditions.

The body's control of heat production and loss to keep core temperature stable. Sweating and skin blood flow are the main cooling mechanisms, and heat stress raises cardiovascular strain during exercise.

Systematically increasing training stress over time so the body continues to adapt. Increases in load, volume, or frequency must be gradual enough to avoid excessive fatigue or injury.

Organizing training into planned phases with varying volume and intensity to peak at key times and reduce overtraining risk. Cycles typically progress from general preparation to specific competition work.

The principle that training adaptations are specific to the muscles, energy systems, and movement patterns stressed. Training should resemble the demands of the target activity or sport.

A subjective scale, often 6 to 20 or 0 to 10, used to estimate exercise intensity. It complements heart rate and is useful when physiological monitoring is impractical.

A practical intensity check based on whether a person can speak comfortably during exercise. Being able to converse suggests moderate intensity; difficulty speaking suggests vigorous intensity.

Early management of soft-tissue injury using rest, ice, compression, and elevation to limit pain and swelling. Current guidance often adds protection and gradual loading rather than prolonged rest.

A series of controlled movements that raise body temperature and prepare joints and muscles for activity. It typically improves range of motion and readiness more than passive stretching alone.

A state of prolonged fatigue and performance decline caused by excessive training stress with inadequate recovery. Signs include persistent soreness, sleep problems, mood changes, and reduced motivation.

A person's belief in their ability to succeed at a specific task. Strong self-efficacy supports effort, persistence, and adherence to exercise programs, and it grows through mastery experiences.

A motivational framework stating that satisfying autonomy, competence, and relatedness needs produces more internalized, lasting engagement. Controlling environments tend to undermine intrinsic motivation for activity.

A behavior-change framework describing stages from precontemplation through contemplation, preparation, action, and maintenance. Interventions are matched to a person's current stage rather than applied uniformly.