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Fitness Words And Terminology Explained

Here are a list of some common and not so common fitness words and terminology with a brief explanation of each.

ADP (Adenosine Diphosphate)

An organic compound integral to metabolism and the flow of energy in your body. When combined with CP compounds, lower energy molecules become ATP substance (see below for more information).


Rhythmic, a steady exercise which uses oxygen to oxidise glucose, fats, and proteins to release energy from the working muscles.

Alactic Anaerobic Phosphagen system or process

The fastest source of energy in the body utilised with ATP and CP. Often used in explosive strength and speed activities.

Antagonistic (pairs of muscles)

Most muscles in the body are in opposing pairs. When one contracts, the other relaxes and is stretched, and vice versa. This arrangement is necessary as muscles can only contract (get shorter) when stimulated by motor nerves, they cannot re-stretch themselves.

ATP (Adenosine Triphosphate)

The substance through which all energy to be used in the body is channelled. Once used to supply power to some process, (for example muscle contraction), it must be reformed using energy from other sources (e.g. oxidation of glucose). It is formed when lower energy molecules of ADP combine with CP structures.

Base of Support

The relationship between you and the surface you are performing. Including the points of contact you have with the surface, you are on.

Body Composition

Body Composition is the proportions of fat and lean (non-fat) body mass in the human body.

B.M.I (Body Mass Index)

The estimation of individual’s relative body fat calculated from their height and weight. The formula for calculating BMI is weight in kilograms (kg) divided by height in meters (m) squared. BMI-specific tape measures can track this very easily.

National Institutes of Health states that BMI can help classify your weight as follows:

Underweight = <18.5

Normal weight = 18.5-24.9

Overweight = 25-29.9

Obesity = BMI of 30 or greater


A measure of energy expenditure. Often referred to in diet and exercise calories are described as kilocalories (kcal) – 1000 of the calories mentioned in science labs for measuring chemical reactions. 

Cardiac Output

The amount of blood pumped out by the heart per minute. Stroke x Heart Rate = Output Volume Rate.

Centre of Gravity (of the body)

The point about which your body weight is evenly distributed.

Concentric (muscle action)

Concentric muscle action is when the force produced is enough to overcome external resistance and the muscles shorten as they contract. When they reduce typically (e.g. in a biceps curl), it is also known as an isotonic contraction. When the shortening is stopped by a constant resistance, it is also called an isometric contraction.


Sudden, often uncontrollable and painful contraction of a muscle or a group of muscles that may last for only seconds, or hours. Of unknown cause, but the loss of salts can be a cause. Cramp is easily treated by stretching and massage.

Creatine Phosphate (CP)

An energy reserve in the muscles that is used to regenerate ATP after it has been used in muscle contractions. ADP + CP => ATP + C

Distributed Practice

Practise of activity with rest breaks in the practice session.

Eccentric (muscle action)

When a muscle is trying to contract while being lengthened by stretching (e.g. the thigh muscles while running down hill).

Endocrine Glands

Glands without ducts (tubes) which produce hormones, and pass them directly into the bloodstream (e.g. pituitary, thyroid, and adrenal glands).


The bodies ability to keep going for long periods. Includes cardiovascular-respiratory (heart-breathing) endurance, and muscular endurance.


Chemicals (proteins) produced by living organisms, which act as catalysts (i.e. they speed up the chemical reaction rate in the body) without themselves being used up in the reaction.


Getting rid of poisonous waste products produced by the body, e.g. carbon dioxide (by breathing out), and urea in the urine from the kidneys.


Involves exertion of the body. It is important in maintaining general health and includes cardiovascular-respiratory (heart-breathing) endurance, muscular endurance, strength, mobility, flexibility and body composition. (See also Physical fitness).


‘Speed play’- running as you please, fast and slow, over different terrains.


Energy-rich substances (e.g. butter, oils, etc.)

Fine Motor Skills

The involvement of movements using small groups of muscles, in particular, actions (e.g. wrist action in table tennis).

Goal setting

The process of setting performance targets or goals, and organising ways of achieving these objectives. Goals should be Specific, Measurable, Agreed, Realistic, Time-phased, Exciting and Recorded – SMARTER.

Gross Motor Skills

Skills which include large groups of muscles (e.g. discus throwing).


A state of complete physical, mental and social well-being, and not only the absence of disease or infirmity.


Chemical messengers produced by an endocrine gland. Even minuscule amounts have powerful effects on the body (e.g. adrenaline ‘pumps the body up’ for activity).

Isometric Muscle 

When a muscle begins to contract and shorten but is then stopped by a constant resistance (e.g. trying to lift a weight that is too heavy for you to move).

Isotonic Muscle Action

A muscle action, when the muscle shortens as it produces movement.

Interval Training

Training with alternating work intervals and rest intervals (e.g. 6 x 200m with 60 seconds rest between each 200m run).

Inverted-U Theory

Motivation (arousal) increases to an optimum point, at which performance is at its best, past which control and quality of return decrease through trying too hard and becoming anxious.

Involuntary Muscle

The muscle that you cannot control by your conscious decisions.


A measure of energy. 4.2 joules = 1 calorie.


A kilojoule is a unit of energy. It also refers to the energy value of food and the amount of energy our bodies’ burn. The common term for this used for this used to be ‘calorie’. Fats and alcohol are the most energy-dense foods.

Knowledge of Performance (KP)

Feedback in which a performer receives information about the quality of their performance regarding movement, style, etc. When given by a coach/video it is extrinsic. When felt by the performer it is intrinsic.

Knowledge of Results (KR)

This is a type of feedback in which a performer receives information about the results of their actions. When given by a coach/video it is extrinsic. When seen/heard directly by the performer it is intrinsic.

Lactic Acid

Produced by working muscles without enough oxygen (anaerobically). The increased acidity stimulates faster breathing and causes muscle pain.

Lactic Anaerobic System

The energy is released from glycogen (glucose) without using oxygen (anaerobic) and which results in the production of lactic acid in the muscles.

Manual/Mechanical Guidance

Physical help in learning what to do.

Massed Practice

The practice of activity without any rest breaks in the practice session.

Metabolic Equivalent of Task (MET),

The metabolic equivalent is a physiological measure of the energy cost of physical activities as the ratio of metabolic rate and the rate of power consumption during physical activities metabolic rate, set by convention to 3.5 ml O2kg−1min−1 or equivalent. 

For example, climbing the stairs is considered to be around 4.0 METs.


Motivation reflects the commitment and determination of a performer. It is a general level of arousal (intensity) to action. It involves a sense of purpose, direction, and sustainment. Intrinsic motivation is when the source of motivation comes from the individual (enjoyment, satisfaction), and extrinsic motivation is when the source of motivation comes from a source other than yourself (prizes, money, etc.).

Motor Programme

Patterns of muscle commands recorded in the central nervous system which can be used quickly when needed.

Motor Skill Or Movement

Motor skill can be defined as the learned ability to perform in a physical activity efficiently, successfully, and consistently’.

Movement Time

The time it takes actually to move as a result of the brain sending nerve impulses to the muscles. Part of the response time.

Open Skills

These are performed in situations which are continually changing so that the performer has to adapt the power to the changing situation (e.g. tackling in football).

The Overload Principle

This is an essential sports fitness training concept. It means that to improve, athletes must continually work harder as they their bodies adjust to existing workouts

Oxygen Debt

The amount of oxygen taken up after intense exercise has stopped. It is needed to oxidise the lactic acid that was produced by the release of energy from glucose without oxygen (anaerobically) during the intense activity. See also Oxygen deficit.

Oxygen Deficit

The amount of oxygen a performer is short of during intense exercise in which they are getting energy from glucose without oxygen (anaerobically). (See also Oxygen debt).

Progressive Loading (Overload of Training)

Increasing the training effort in carefully controlled stages – not overloading in the sense of overstraining the body and its systems which could lead to injury.


Substances which build and repair the body, especially muscle. Protein containing foods must be eaten every day (e.g. meat, eggs, cheese, nuts, soya beans, etc.)

Reaction Time

The time it takes for the brain to receive information, to decide what to do, and to send impulses to the muscles. Part of the response time.

Recovery Position

The position to place an injured person into if it’s possible and safe to do so.

Response Times

The time frame in which it takes to respond to a stimulus (e.g. the actions of people).

Response = Reaction Time + Movement Time

Where the reaction time is the time it takes the brain to receive information, to decide what to do and to send impulses to the muscles. The movement time is the time it takes actually to move.

Reversibility (of training)

Improvements in fitness as a result of training are not permanent; they are quickly lost (reversed) if training stops.

Sensory Input

Information received from the senses (e.g. sight, sound, touch, taste, smell) and feelings.


The classification of body types (physiques) by basic skeletal structure into endomorph, mesomorph, and ectomorph categories. Knowing your Somatotype can help structure the right fitness programmes for you.

Specificity (of training)

Different types of training improve different (specific) parts and systems of the body (e.g. cycling will not help a swimmer improve their swimming).

Stability Of The Body

The equilibrium or balance of the body on a base, with increased area of the base either wider or larger, the centre of gravity is lowered, or the centre of gravity is moved closer to the ground. 

State Anxiety

Anxiety caused by/related to a particular situation (e.g. a rock face).


A pain in the chest/abdomen region associated with running. Of unknown cause, but possibly a result of the jarring action of running on the liver, which is suspended below the diaphragm on the right-hand side.


Force produced by working muscles contracting. Including static or isometric strength, where effort is made to a constant resistance and dynamic or isotonic strength where effort moves a resistance.


Exercise to improve flexibility. This can be passive (e.g. limb being pushed to the limit of movement by a partner) active (e.g. moving and holding your own stretch position) and ballistic (e.g. swinging arms and/or legs).

Stroke Volume

As the ventricles of the heart contract, this the amount of blood pumped.

Trait Anxiety

A personality factor (trait) – the tendency to become anxious in almost all situations.

Variation Of Training

The inclusion of varied to prevent boredom or staleness occurring and injuries developing. Variation should always be safe.


The growth of new capillary networks in muscles working aerobically over extended periods of time. It increases their potential blood supply, and, therefore, their oxygen supply during aerobic exercise. Similar changes as a result of aerobic training occur within the coronary arteries of the heart muscle.

VO2 Max

The maximum oxygen uptake or volume of oxygen that can be utilized in one minute during maximal or exhaustive exercise that is measured in millilitres of oxygen per minute per kilogram of body weight.

Millilitres (density of oxygen is about 1.429 g/litre at STP. That’s 1429 mg/1000 ml or 1.429 mg/ml for your answer).

Warm-down (cool down)

A warm-down brings the mind and the body back to a relaxed state, helping to reduce the risk of injury.

Warm Up

The gradual increase in the heart rate and breathing rate with a slight rise in body temperature which prepares the mind and the body for activity, helping to reduce the risk of injury.

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