IFPA PFT key terms

The muscle that produces the primary force for a given movement, shortening or lengthening to create joint action. It works in coordination with synergists and in opposition to antagonists.

The muscle positioned on the opposite side of a joint from the agonist, which relaxes or lengthens to permit the intended movement. It also protects the joint by controlling the return phase.

A muscle that assists the agonist by adding force, stabilizing a joint, or neutralizing unwanted motion. Synergists help movements stay efficient and reduce strain on the primary mover.

A muscle or muscle group that holds a body segment or joint steady while another part moves. Stability prevents unwanted motion and lets the prime mover work safely under load.

The nervous system's automatic relaxation of a muscle on one side of a joint when the opposing muscle contracts. It allows smooth movement and is the basis for many flexibility techniques.

The explanation of muscle contraction in which actin filaments slide over myosin filaments, shortening the sarcomere. Calcium and ATP drive the process through cross-bridge cycling.

A single motor neuron together with all the muscle fibers it activates. Recruiting more motor units, or larger ones, increases the force a muscle can produce.

A slow-twitch fiber rich in mitochondria and capillaries, resistant to fatigue but low in peak force. It supports posture and prolonged, low-intensity activity such as walking or endurance exercise.

A fast-twitch fiber that generates high force quickly but fatigues sooner than slow-twitch fibers. It is recruited for sprinting, jumping, and heavy resistance work.

The increase in muscle force achieved by raising the frequency of nerve impulses sent to already active motor units. It complements recruitment when greater tension is required.

The body's sense of joint position, movement, and force, fed by receptors in muscles, tendons, and joints. Good proprioception supports balance, coordination, and safe technique.

A stretch-sensitive receptor inside skeletal muscle that detects changes in length and speed of lengthening. It triggers a reflex contraction that helps protect the muscle from overstretching.

A receptor at the junction of muscle and tendon that senses tension. When tension is high it can inhibit the muscle, reducing force output and lowering injury risk.

The volume of blood the heart pumps per minute, calculated as heart rate multiplied by stroke volume. It rises during exercise to deliver more oxygen to working muscles.

The amount of blood ejected from the heart with each beat. Endurance training typically increases stroke volume, allowing a lower resting heart rate for the same output.

The maximum rate at which the body can take up and use oxygen during intense exercise, usually expressed in milliliters per kilogram per minute. It is a key marker of aerobic fitness.

The exercise intensity at which blood lactate begins to accumulate faster than it can be cleared. Training near this point improves endurance performance and the ability to sustain pace.

The intensity above which oxygen supply cannot fully meet demand, so the body relies more on anaerobic energy. It closely relates to the lactate threshold and limits sustainable effort.

Excess post-exercise oxygen consumption: the elevated oxygen use after exercise as the body restores energy stores, clears byproducts, and returns to baseline. It contributes a small extra calorie burn.

The immediate energy system that uses stored ATP and phosphocreatine for brief, explosive efforts lasting roughly ten seconds or less. It recovers quickly between efforts.

The energy pathway that breaks down glucose without oxygen to produce ATP for high-intensity efforts of roughly ten seconds to two minutes. It produces lactate as a byproduct.

The principle of gradually increasing training stress, such as load, volume, or difficulty, so the body continues to adapt. Without it, progress stalls; with too much, injury risk rises.

The principle that training adaptations are specific to the muscles, energy systems, and movement patterns trained. Programs should mirror the client's goals and demands.

The planned organization of training into phases with varying volume and intensity over time. It manages fatigue, reduces plateaus, and peaks performance for a target date.

A planned period of reduced training volume or intensity, usually lasting about a week. It allows recovery and supercompensation so the client returns stronger and fresher.

A state of prolonged fatigue and declining performance caused by excessive training without adequate recovery. Signs include sleep problems, mood changes, soreness, and reduced motivation.

A subjective scale, often from 6 to 20 or 1 to 10, on which a client rates how hard exercise feels. It helps set and adjust intensity without relying only on heart rate.

The difference between maximum and resting heart rate, used with the Karvonen method to set target zones. It accounts for individual fitness better than a simple percentage of maximum.

A widely used pre-participation screening questionnaire that identifies people who may need medical clearance before exercise. Positive answers prompt follow-up before training begins.

A client's voluntary agreement to participate after understanding the risks, benefits, and alternatives of the program. It should be documented and revisited when circumstances change.

The legal and professional boundaries of what a fitness professional may do, based on training and certification. It excludes diagnosis, prescribing treatment, and providing medical or dietetic care.

Directing a client to a qualified professional, such as a physician, physical therapist, or registered dietitian, when needs exceed the trainer's scope. It protects both client and trainer.

An objective stated as specific, measurable, achievable, relevant, and time-bound. Clear goals guide program design and give the client a way to track progress.

A communication skill in which the trainer gives full attention, reflects back what was heard, and asks clarifying questions. It builds trust and uncovers barriers to adherence.

An acute soft-tissue injury response: rest, ice, compression, and elevation. It aims to limit swelling and pain in the first day or two before graded return to activity.

The ability of the trunk and pelvic musculature to control spine position and transfer force between the upper and lower body. It supports safe lifting and efficient movement.

A flexibility method using contract-relax or hold-relax cycles of muscle contraction followed by stretch. It can improve range of motion quickly but needs careful technique.

The relationship between calories consumed and calories expended. A surplus supports weight gain, a deficit supports weight loss, and balance maintains current body weight.

The energy the body uses at rest to maintain vital functions, typically the largest part of daily calorie expenditure. It is influenced by body size, composition, age, and sex.

One of the three energy-yielding nutrients: carbohydrate, protein, and fat. Each supplies a different amount of energy and serves distinct roles in fueling and recovery.