AFAA GFI key terms

The opening phase of a class that raises heart rate, warms tissues, and rehearses movement patterns at low intensity so participants are prepared for the main workout.

The closing phase of a class that gradually lowers heart rate and returns blood flow toward resting levels, often including static stretching and breathing.

Active movement through a joint's full range of motion, such as leg swings or arm circles, used to prepare the body for activity rather than to hold a stretch.

Holding a muscle in a lengthened position for a set time, typically after activity, to support relaxation and maintain flexibility without prepping for explosive work.

The extent of movement available at a joint or through a movement pattern, which instructors manage by cueing appropriate depth and alignment.

Positioning bones and joints so load passes safely through them, for example keeping knees tracking over toes during a squat.

The natural inward curve of the lower back and outward curve of the upper back, maintained as a baseline posture to reduce stress on the spine.

Coordinated activation of deep trunk muscles to brace the spine and pelvis, providing a stable base for limb movement during standing and floor exercises.

A muscle action in which the muscle shortens while producing force, such as lifting the body during a biceps curl or rising from a squat.

A muscle action in which the muscle lengthens under tension while controlling load, such as lowering into a squat or a slow biceps curl descent.

A muscle action in which tension develops without a change in muscle length, such as holding a plank or a wall sit.

The primary muscle producing a desired movement, for example the quadriceps during knee extension.

The muscle opposing the agonist at a joint, which lengthens and helps control the movement, such as the hamstrings during knee extension.

The muscle or muscle group most responsible for generating a given joint action, used when choosing exercises to target a body area.

The three imaginary planes (sagittal, frontal, transverse) through which the body moves, used to vary exercises and train movement in multiple directions.

Programming movements that cross more than one plane, such as adding rotation or side-to-side steps, to train the body in varied directions.

A bone acting as a rigid bar that rotates around a joint under muscle force, explaining why longer limbs and load placement change effort.

The rotational effect of a force applied at a distance from a joint axis, which increases when load is moved farther from the body.

The downward force acting on the body that determines how much load a movement creates and how posture and position change difficulty.

Resistance training that uses the participant's own mass as the load, with difficulty adjusted by leverage, position, and range of motion.

Adenosine triphosphate, the molecule that supplies immediate energy for muscle contraction and is replenished by the body's energy systems.

The immediate energy pathway that uses stored ATP and creatine phosphate for brief, very intense efforts lasting roughly ten seconds or less.

Energy production without relying on oxygen, dominant in short bursts of high-intensity work such as sprints or heavy resistance sets.

The oxygen-dependent energy pathway that fuels sustained, moderate-intensity activity and supports recovery between harder efforts.

The intensity at which lactate accumulates in the blood faster than it is cleared, marking a point where sustained effort becomes difficult.

Continuous aerobic work at a relatively constant intensity, used to build endurance and cardiorespiratory efficiency.

Alternating periods of higher-intensity work with recovery or lower-intensity periods, used to raise fitness and manage fatigue in class.

The difference between maximum and resting heart rate, used with percentages to set target training intensities for participants.

A range of heart rates associated with a desired training intensity, used to monitor and adjust effort during cardiorespiratory segments.

A self-reported scale of effort used to gauge exercise intensity when heart rate monitoring is unavailable or unreliable.

A simple intensity check based on whether a participant can speak comfortably, with harder breathing indicating higher effort.

Systematically increasing exercise demand over time through intensity, volume, complexity, or reduced rest so participants continue to adapt.

Modifying an exercise to make it easier or safer by reducing range, load, speed, or complexity, allowing participants to work at an appropriate level.

An adjustment to an exercise or cue that changes difficulty, impact, or joint stress so it fits a participant's needs while keeping the class moving.

The concept that the body adapts only when challenged beyond its current capacity, requiring planned increases in training demand.

The principle that training adaptations are specific to the type of stress applied, so class design must match the desired outcome.

Spoken instruction that tells participants what to do, where to move, and how to adjust effort, delivered clearly and in advance of the movement.

A demonstration or gesture showing a movement or correction, used alongside words so participants can see what is expected.

The combined verbal, visual, and kinesthetic signals an instructor uses to guide timing, technique, and intensity during class.

The personal space a person can reach with limbs without moving the feet, used to plan safe spacing and movement directions in class.

Knowing where the body is in relation to others and to equipment, which supports safe spacing and smooth transitions during group movement.

The planned sequence of movements and transitions in a class, structured to fit the music, the goal, and participants' skill level.

The speed of the music measured in beats per minute, chosen to match the intended movement speed and intensity.

Muscle discomfort appearing roughly a day or more after unfamiliar or intense exercise, usually easing with light activity and recovery.

A first-aid approach for acute soft-tissue injury: rest, ice, compression, and elevation, used to limit swelling and pain.

Practices such as proper warm-up, safe alignment, appropriate progression, and clear instruction that reduce the chance of harm in class.

A participant's voluntary agreement to take part after being told about the activity, its risks, and what to expect.

Collecting health history and risk information before exercise so the instructor can identify participants who need medical clearance or modifications.

The boundaries of what an instructor is trained and legally allowed to do, which excludes diagnosing, treating, or prescribing for medical conditions.

The instructor's legal responsibility for harm caused by negligent instruction, reduced by proper screening, safe cueing, and carrying insurance.

Failure to provide the care a reasonable instructor would provide, such as ignoring unsafe conditions or giving inappropriate exercise guidance.

A prepared procedure for responding to injury or sudden illness in class, including who calls for help and how to access equipment.

The overall structure and emphasis of a session, such as strength, dance, cycling, or mind-body, which guides exercise selection and music.

The sequence in which movements are performed in a class, arranged to manage fatigue, balance muscle groups, and keep transitions safe.

The ability of a muscle group to sustain repeated contractions over time, a common target of higher-repetition group fitness work.

The ability to move a joint or muscle group through its available range, supported by warm-up, stretching, and consistent practice.

The alignment of body segments against gravity at rest or during movement, which affects breathing, balance, and load on joints.

The ability to keep the body's center of mass over its base of support, trained through single-leg and unstable-position exercises.