The SEHS glossary

The dark band of a sarcomere, equal to the length of the myosin filaments, which stays the same length during contraction.

A movement in the frontal plane that takes a body part away from the midline of the body, such as raising the arm sideways at the shoulder.

A stable, enduring and largely inherited trait, such as balance, coordination or reaction time, that underlies the performance of a range of skills.

A superficial wound in which the outer layers of skin are scraped off by friction against a rough surface, such as a graze from a fall on a road or artificial pitch.

The rate of change of velocity, $a = \frac{(v-u)}{t}$; a vector measured in m s⁻². A negative acceleration, a decrease in velocity, is called deceleration.

The physiological adaptations that develop with repeated or continuous exposure to a stressful environment such as heat, cold or altitude, reducing its strain on the body and improving performance in it.

How close a measured or calculated value is to the true or accepted value of the quantity.

A neurotransmitter released by motor neurons at the neuromuscular junction, which binds to receptors on the sarcolemma and starts a muscle action potential.

A theory proposing that people strive to feel successful and competent, and judge success either against their own previous performance (task orientation) or against other people (ego orientation).

A person’s drive to strive for success, master tasks and do well in situations where their performance can be evaluated against a standard or against other people.

A fall in muscle or blood pH caused by hydrogen ions accumulating faster than they are buffered during high-intensity exercise; it inhibits enzymes such as phosphofructokinase and calcium binding.

The thin protein filament of the sarcomere, anchored to the Z lines, which has binding sites for myosin heads and is pulled towards the centre of the sarcomere during contraction.

Low-intensity exercise performed after training or between bouts to keep blood flow high and speed the removal of metabolites such as lactate and hydrogen ions.

An illness caused by rapid ascent to high altitude, usually above about 2,500 m, with headache, nausea, fatigue, dizziness and poor sleep, which usually ease within a few days.

An immediate, short-term change in the body during or just after a single bout of exercise, which returns to resting values during recovery.

An injury caused by a single, sudden or excessive application of force, or by a force from an unexpected direction, such as a ligament torn in a tackle or a bone broken in a fall.

A movement in the frontal plane that brings a body part towards the midline of the body, such as lowering the arm from the side back to the trunk.

The molecule left when ATP loses its terminal phosphate group and releases energy; it is rebuilt into ATP with inorganic phosphate using energy from the breakdown of fuels.

A molecule made of adenosine and three phosphate groups that is the immediate source of energy for muscle contraction; energy is released when the bond to its terminal phosphate is broken.

A pair of endocrine glands on top of the kidneys; the adrenal medulla releases epinephrine and norepinephrine, and the adrenal cortex releases hormones such as cortisol and aldosterone.

Describes a process that requires oxygen, such as the resynthesis of ATP by the oxidative system in the mitochondria.

The part of the peripheral nervous system that carries nerve impulses from receptors towards the central nervous system; also called the sensory division.

An opportunity for action that the environment offers a particular performer, depending on both the environment and the performer's capabilities, for example a gap that affords a pass.

A skill-related component of fitness: the ability to change the direction of the whole body quickly and accurately while maintaining control.

The muscle that contracts to produce a particular movement at a joint; also called the prime mover.

A Big Five trait describing how well an individual relates to others and acts in ways that preserve relationships, being cooperative, trusting and considerate.

The mass of air per unit volume, about 1.2 kg per cubic metre at sea level; it falls as altitude, temperature and humidity rise, reducing drag and lift.

Drag acting on a body moving through air; it opposes the body's motion and increases as the body's speed increases.

A hormone secreted by the adrenal cortex that increases reabsorption of sodium, and excretion of potassium, by the kidneys, so that water follows by osmosis and blood volume is maintained.

The principle that when a motor neuron is stimulated above its threshold, all the muscle fibres of that motor unit contract fully, and below threshold none of them contract.

A statement that there is a real difference between conditions or a real relationship between variables, accepted when the data allow the null hypothesis to be rejected.

Training or living at altitude, usually about 1,800–3,000 m, or in simulated low-oxygen conditions, to increase red cell mass and haemoglobin and so improve endurance performance.

Tiny, thin-walled air sacs at the ends of the bronchioles, surrounded by capillaries, where oxygen diffuses into the blood and carbon dioxide diffuses out of it.

The building block of proteins; an organic molecule containing a nitrogen-containing amino group and an acid group, of which twenty kinds are found in human proteins.

The absence of motivation, which occurs when a person perceives no link between their effort and the outcome, or places no value on the activity.

A condition in which the blood's haemoglobin concentration or number of red blood cells is below normal, reducing its ability to carry oxygen; iron deficiency is the most common cause.

Describes a process that takes place without oxygen, such as the resynthesis of ATP by the phosphagen and glycolytic systems in the sarcoplasm.

The standard reference posture from which positions and movements are described: standing upright facing forward, feet slightly apart, arms by the sides and palms facing forward.

The angle between the long axis of a body, such as a discus, javelin or ski jumper, and the direction of the fluid flow relative to it; it determines how much lift and drag are produced.

The angle to the horizontal at which a projectile is released or takes off, also called the angle of projection; it decides how the speed of release is shared between horizontal and vertical motion.

The quantity of rotation possessed by a rotating body, equal to its moment of inertia multiplied by its angular velocity; measured in kg m² s⁻¹.

Movement of a body or body segment along a circular path about an axis of rotation, so that different parts travel different distances; also called rotation.

The angle turned through by a rotating body per unit of time, in a stated direction, measured in rad s⁻¹; linked to linear velocity by $v = \omega r$.

The muscle on the opposite side of a joint to the agonist, which relaxes and lengthens to allow the agonist to produce a movement.

Two muscles on opposite sides of a joint that produce opposite movements, so that one acts as the agonist while the other acts as the antagonist, such as the biceps and triceps brachii.

A positional term meaning towards the front of the body, also called ventral, for example the patella is anterior to the knee joint.

A ligament inside the knee running from the back of the femur to the front of the tibia, which stops the tibia sliding forward on the femur and limits rotation of the knee.

A collection of standardised body measurements from a large, defined sample of people, used to describe a population's dimensions and percentiles and to design and size equipment.

The measurement of the size, shape, proportions and composition of the human body, including stature, body mass, segment lengths, breadths, girths and skinfolds.

The increase in heart rate and other sympathetic responses before exercise begins, caused by sympathetic stimulation and the release of epinephrine in response to the expectation of exercise.

A hormone made by the hypothalamus and released by the posterior pituitary when the blood is too concentrated, which increases water reabsorption by the kidneys; also called vasopressin.

A negative emotional state characterised by nervousness, worry and apprehension, associated with activation or arousal of the body.

The bones of the upper and lower limbs together with the shoulder and pelvic girdles that attach them to the axial skeleton; its main function is movement.

Behaviour in which a person seeks out and engages with achievement situations, for example choosing realistic challenges, persisting after failure and welcoming evaluation.

A principle stating that the buoyant force on a body immersed in a fluid equals the weight of the fluid the body displaces.

The level of physiological and psychological activation of a person, varying on a continuum from deep sleep to intense excitement.

A small branch of an artery leading into a capillary network, whose muscular wall narrows or widens to control how much blood flows into the capillaries it supplies.

The difference between the oxygen content of arterial and mixed venous blood, usually in mL of oxygen per 100 mL of blood, showing how much oxygen the tissues extract.

A blood vessel that carries blood away from the heart under high pressure, with a thick wall of smooth muscle and elastic tissue and a relatively narrow lumen.

The smooth layer of hyaline cartilage covering the ends of bones in a synovial joint, which reduces friction between the bones and absorbs and spreads load.

A joint: a place where two or more bones meet, classified by structure as fibrous, cartilaginous or synovial.

One of the four broad skills the course assesses: demonstrating knowledge (AO1), understanding and applying knowledge (AO2), analysing, evaluating and synthesising (AO3), and carrying out insightful, ethical investigations (AO4).

The second, practice phase of learning, in which subroutines are linked, errors become fewer and smaller, and the learner begins to use intrinsic feedback.

The build-up of fatty plaques of lipid, cholesterol, immune cells and fibrous tissue in the walls of arteries, which narrows them, reduces their elasticity and can lead to a blocking blood clot.

The enlargement of the heart, especially the left ventricle, caused by regular intense training, which increases stroke volume and maximal cardiac output as a healthy adaptation.

A group of specialised cells between the atria and ventricles that receives the impulse from the atria and delays it by about 0.1 s before passing it to the bundle of His.

One of the two thin-walled upper chambers of the heart, which receives blood from the veins and pumps it into the ventricle below.

A decrease in the size of a muscle caused by a loss of contractile proteins from its fibres, usually because of disuse, immobilisation, injury, illness, ageing or malnutrition.

The process of focusing mental resources on selected information from the environment or from within the body, while ignoring other information.

The direction (internal or external) and width (broad or narrow) of a person's attention at a particular moment, meaning what they attend to and how much information they take in.

A reduction in the width of attention as arousal increases, so that fewer cues are processed and, at high arousal, relevant cues are missed.

A stable, preferred pattern of coordination, such as walking or running, that a movement system settles into because it is efficient under the current constraints.

The reason an individual gives to explain the cause of an outcome, such as a success or a failure, for example ability, effort, task difficulty or luck.

An intervention that teaches individuals to attribute failure to unstable, controllable causes such as effort or strategy, rather than to stable, uncontrollable causes such as lack of ability.

A theory describing how individuals explain the causes of their successes and failures, and how these explanations affect their emotions, expectations, confidence and future behaviour.

A relaxation technique in which an individual repeats self-suggestions about sensations such as heaviness and warmth in the limbs and a calm heartbeat to produce deep relaxation.

The branch of the efferent division that controls involuntary functions through cardiac muscle, smooth muscle and glands; it has sympathetic and parasympathetic divisions.

Motivation in which an activity is done with a full sense of choice because it is enjoyable, interesting or personally valued, so that it is experienced as an end in itself.

The final phase of learning, in which the skill is performed automatically, consistently and efficiently with little conscious attention, and the performer corrects their own errors.

The basic psychological need to feel that one’s behaviour is self-chosen and self-endorsed, so that one is the origin of one’s own actions rather than pushed by outside pressure.

A general tendency to act out of interest in and valuing of what is happening, to seek choice and to treat events as sources of information.

Behaviour in which a person withdraws from or minimises involvement in achievement situations, for example avoiding competition, choosing very easy or very hard tasks, withdrawing effort or making excuses.

Coping strategies that try to prevent the negative impact of a stressor by physically or psychologically distancing oneself from it, such as ignoring, procrastinating, distraction or quitting.

The part of the skeleton forming the central axis of the body (skull, vertebral column, ribs and sternum), whose main functions are protecting vital organs and supporting the body.

An imaginary line about which a body or body segment rotates, passing through the joint or centre of mass and lying at right angles to the plane of movement.

A skill-related component of fitness: the ability to keep the centre of mass over the base of support, either when stationary (static) or when moving (dynamic).

A multiaxial synovial joint in which a ball-shaped head fits into a cup-shaped socket, allowing movement in all three planes including rotation and circumduction, such as the hip and shoulder.

A stretch receptor in the walls of the aortic arch and carotid arteries that detects changes in blood pressure and informs the cardiovascular control centre.

The minimum rate of energy expenditure needed to maintain essential body functions at complete rest, measured lying down, awake, after fasting and in a comfortable temperature.

The area enclosed by the outermost points of contact between a body and the supporting surface, including the area between those points.

Measuring an individual's fitness and related values before a training programme begins, so that intensities can be set and later progress compared with the starting point.

The three innate needs for autonomy, competence and relatedness that, according to self-determination theory, must be satisfied for optimal motivation, development and well-being.

A mini-theory of self-determination theory proposing that well-being and optimal functioning depend on satisfying the needs for autonomy, competence and relatedness, and that thwarting any of them leads to ill-being.

A principle stating that the pressure in a moving fluid falls as its speed increases, so a body with faster flow over one side is pushed towards that lower-pressure side.

The process in the mitochondria that breaks fatty acids down into two-carbon units of acetyl coenzyme A, which then enter the Krebs cycle.

A model that describes personality with five broad traits (openness to experience, conscientiousness, extraversion, agreeableness and neuroticism), each measured on a continuum from low to high.

The transfer of learning from one side of the body to the other, for example from the dominant to the non-dominant foot or hand.

A technique in which devices measure a physiological variable such as heart rate, heart rate variability, skin conductance or muscle activity and display it, so the individual learns to control it voluntarily.

Lang's theory that an image is stored as stimulus propositions about the situation and response propositions about the person's reactions, and that imagery is most effective when it includes the responses.

A faulty movement pattern, often developed through habit, fatigue, weakness or previous injury, that places abnormal or excessive load on a tissue and increases the risk of injury.

The study of the forces acting on and within the human body and the effects of these forces on movement, applying the laws of mechanics to sport, exercise and health.

A method of reducing bias by withholding which condition a participant is in from the participant (single-blind) or from both the participants and the researchers who measure them (double-blind).

A pocket of fluid between layers of skin caused by repeated friction, for example between a shoe and the heel; a cumulative skin injury.

Practising one skill, or one version of a skill, repeatedly before moving on to the next, which improves performance quickly during practice.

The homeostatic control of blood glucose concentration by negative feedback, in which the pancreas releases insulin when glucose rises and glucagon when it falls.

A measure of the hydrogen ion concentration of the blood; the more hydrogen ions, the lower the pH. Normal arterial pH is about 7.35–7.45.

The force exerted by blood on the walls of the blood vessels, usually measured in the large arteries in mmHg and written as systolic over diastolic pressure, such as 120/80 mmHg.

The change in the distribution of cardiac output during exercise, in which vasodilation increases flow to working muscles and vasoconstriction reduces flow to less active organs such as the gut and kidneys.

The relative proportions of fat mass and fat-free mass (muscle, bone, organs and water) in the body, usually expressed as body fat percentage.

Body mass in kilograms divided by the square of height in metres, used to classify adults as underweight, healthy, overweight (25–29.9) or obese (30 or more); it does not distinguish fat from muscle.

The total volume of water contained in the body, about 55–60% of body mass in adults, divided between the intracellular fluid and the extracellular fluid.

The rightward shift of the oxygen–haemoglobin dissociation curve caused by more carbon dioxide, higher acidity and higher temperature, so haemoglobin releases more oxygen at a given pO₂.

A hard, living connective tissue whose matrix of collagen is hardened with calcium phosphate; bones support and protect the body, act as levers for movement, store minerals and produce blood cells.

The amount of mineral, mainly calcium, per unit area or volume of bone, measured by a DXA scan and used as an index of bone strength.

The thin layer of fluid next to the surface of a moving body, slowed by friction with that surface; where it separates from the body decides the size of the wake.

A controlled breathing technique with four equal phases, usually of 4 seconds each: breathe in, hold, breathe out, hold; it slows breathing and lowers heart rate and arousal.

A resting heart rate below 60 beats min⁻¹; in trained endurance athletes a normal result of a large stroke volume and high parasympathetic activity.

Attention that takes in a wide range of cues at the same time, used to assess a changing situation or to plan.

A type of fat tissue, plentiful in newborns and present in smaller amounts in adults, whose mitochondria release energy from fat directly as heat in non-shivering thermogenesis.

A substance in a body fluid that resists changes in pH by combining with or releasing hydrogen ions; the main blood buffer is hydrogen carbonate (bicarbonate).

A bundle of specialised conducting fibres that carries the impulse from the AV node down the septum of the heart, dividing into left and right bundle branches.

The upward force exerted by a fluid on a body that is partly or wholly immersed in it, equal to the weight of the fluid the body displaces.

A syndrome of physical and emotional exhaustion, reduced sense of accomplishment and devaluation of sport, caused by long-term stress when demands exceed an athlete’s resources.

A small fluid-filled sac lined with synovial membrane between a bone and a tendon, ligament or the skin, which reduces friction where these structures move over one another.

A mineral that gives bones and teeth their hardness and strength and, as calcium ions released from the sarcoplasmic reticulum, triggers muscle contraction; also needed for nerve transmission.

The process of checking a measuring instrument against a known standard and adjusting it, or correcting its readings, so that its measurements are accurate.

The smallest blood vessel, with a wall one cell thick and a lumen about the width of a red blood cell, where substances are exchanged between blood and tissues by diffusion.

A macronutrient made of carbon, hydrogen and oxygen and built from sugar units; the main fuel for moderate and high-intensity exercise, stored in the body as glycogen.

A strategy of eating a very high-carbohydrate diet (about 10–12 g per kg of body mass per day) for 36–48 hours, with reduced training, to maximise muscle glycogen before an endurance event of over 90 minutes.

The sequence of events in one heartbeat: contraction (systole) and relaxation (diastole) of the atria and ventricles, with the opening and closing of the valves.

The volume of blood pumped by the left ventricle per minute, equal to heart rate multiplied by stroke volume and measured in L min⁻¹; about 5 L min⁻¹ at rest.

The ability of the cardiovascular and respiratory systems to supply oxygen to working muscles during sustained whole-body exercise; its best single measure is VO₂ max.

A region of the medulla oblongata that receives information from receptors and higher brain centres and regulates heart rate, force of contraction and blood vessel diameter through the autonomic nervous system.

Any disease of the heart or blood vessels, including coronary heart disease, stroke, peripheral arterial disease and heart failure; most is caused by atherosclerosis.

The gradual rise in heart rate and fall in stroke volume during prolonged steady-state submaximal exercise, with cardiac output roughly maintained, caused by fluid loss and a rising core temperature.

The organ system made up of the heart, blood vessels and blood, which transports oxygen, carbon dioxide, nutrients, hormones, heat and waste products around the body.

A firm, flexible connective tissue without blood vessels, made of collagen fibres in a water-rich matrix, that reduces friction, absorbs shock and gives shape; types are hyaline, fibrocartilage and elastic.

A joint in which the bones are joined by cartilage, usually a fibrocartilage pad, allowing slight movement, such as the joints between vertebrae and the pubic symphysis.

A theory proposing that when cognitive anxiety is high, rising physiological arousal improves performance up to a threshold, beyond which performance drops suddenly and dramatically rather than gradually.

A mini-theory of self-determination theory describing relatively stable individual differences in how people orient to their environment, expressed as autonomy, control and impersonal orientations.

A relationship in which a change in one variable directly produces a change in another; shown only by an experiment that changes one variable while controlling the others.

Fatigue originating in the brain and spinal cord, where reduced neural drive recruits fewer motor units or fires them at a lower rate, so less force is produced.

A debated theory that the brain regulates pacing and exercise intensity, using feedback from the body and the expected task duration, so that exercise stops before homeostasis is lost.

The brain and spinal cord, which receive sensory information from the whole body, integrate it and send out instructions to muscles and glands.

The point through which the buoyant force acts, at the centre of the volume of fluid displaced; in a swimmer it usually lies nearer the chest than the centre of mass.

The point at which the whole mass of a body may be considered to be concentrated and through which its weight acts; it moves when body segments move and can lie outside the body.

The component of mental toughness describing the tendency to appraise difficult situations, change and setbacks as opportunities for growth rather than as threats.

An appraisal in which an individual perceives that their resources are sufficient to meet the demands of a stressful situation, so it is seen as an opportunity for gain or growth.

A receptor that detects changes in the chemical composition of the blood, mainly carbon dioxide, hydrogen ions (pH) and oxygen; found in the medulla and in the carotid and aortic bodies.

A significant drop in the performance of a well-learned skill under pressure, caused by the perceived importance of the situation.

A long-term structural or functional change in the body that results from repeated training over weeks or months and is lost through detraining.

A roughly 24-hour cycle in body processes such as sleep and wakefulness, core temperature and hormone release, controlled by a clock in the hypothalamus and set mainly by light.

A circular movement in which the distal end of a limb traces a circle while the proximal end stays fixed, combining flexion, abduction, extension and adduction across several planes.

A skill performed in a stable, predictable environment that does not affect it, so the movement can be repeated the same way, for example a basketball free throw.

Control of a movement in which feedback received during the movement is compared with a reference of correctness, so that errors can be corrected while it continues.

The proportion of the variation in the dependent variable explained by a trend line, from 0 to 1 (R²); for a straight line it equals the square of the correlation coefficient.

A number with no units describing how strongly two particular surfaces resist sliding, equal to friction divided by the normal reaction force; the static value (μs) exceeds the dynamic value (μd).

A measure of the elasticity of a collision, the relative velocity of separation divided by the relative velocity of approach, $C_\text{R} = \frac{v_\text{b} - v_\text{a}}{u_\text{a} - u_\text{b}}$; no units, between 0 and 1.

The standard deviation expressed as a percentage of the mean (V = 100 × SD ÷ mean), used to compare the relative spread of data sets with different units or means, and the reliability of tests.

The mental component of anxiety, consisting of worry, negative expectations about performance and concern about the consequences of failure.

A mini-theory of self-determination theory explaining how external events such as rewards, feedback and competition affect intrinsic motivation through their effects on perceived autonomy and competence.

Imagery of strategies, tactics, game plans and routines, such as a set play, a race plan or a pre-performance routine.

Imagery used to learn, practise and improve skills (cognitive specific) or strategies and game plans (cognitive general).

The first phase of learning, in which the learner tries to understand the skill; performance is inconsistent with many large errors, and every movement needs conscious attention.

Imagery of performing specific sport skills, such as a tennis serve or a golf swing, used to learn, refine or rehearse them.

A recovery technique in which the body is immersed in cold water, typically 10–15 °C for 10–15 minutes, after exercise to reduce soreness, inflammation and core temperature.

A strong, flexible structural protein forming the fibres of connective tissues; collagen fibres have high tensile strength and stretch very little.

A brief interaction in which two bodies come into contact and exert equal and opposite forces on each other, changing the momentum of each.

A word or phrase in an examination question, such as state, describe, explain or evaluate, that tells the candidate what kind of answer is wanted and the depth of treatment needed.

The component of mental toughness describing an individual’s tendency to set goals and persist with tasks until they are completed, despite obstacles and setbacks.

Dense, solid bone tissue that forms the outer layer of every bone and the walls of the shaft of long bones, resisting bending and compression.

The basic psychological need to feel effective in dealing with the environment and capable of achieving desired outcomes and mastering challenges.

The Competitive State Anxiety Inventory-2, a self-report questionnaire measuring state cognitive anxiety, state somatic anxiety and self-confidence before competition; a revised 17-item version is the CSAI-2R.

The application of external pressure to an injured area, usually with an elastic bandage or tape, to limit bleeding and swelling in the first days after an acute injury.

Tight-fitting garments that apply external pressure to the limbs, worn during or after exercise to reduce swelling and soreness and speed the recovery of muscle function.

The ability to keep attention on the relevant cues of a task for as long as the task requires, resisting the movement of attention elsewhere.

An isotonic contraction in which the muscle shortens while producing tension, because the muscle force is greater than the load.

A traumatic brain injury caused by a blow to the head, neck or body that transmits an impulsive force to the brain, producing a temporary disturbance of brain function rather than visible structural damage.

The transfer of heat by direct contact between the skin and a cooler or hotter solid, liquid or gas, such as cold water or a cold surface.

A biaxial synovial joint, also called an ellipsoid joint, in which an oval convex surface fits an oval concave one, allowing flexion, extension, abduction, adduction and circumduction but not rotation, such as the wrist.

The component of mental toughness describing an individual’s belief in their own abilities to succeed and their assertiveness with others (interpersonal confidence).

An uncontrolled variable that changes along with the independent variable and also affects the dependent variable, so that its effect cannot be separated from the effect being studied.

Tissue that supports, connects and separates other tissues and organs, made of cells in a matrix of protein fibres (mainly collagen) and ground substance; bone, ligament, tendon, cartilage and fascia are examples.

A Big Five trait describing the tendency to control impulses, act in socially acceptable ways and behave in an organised, self-disciplined way that supports goal-directed behaviour.

The principle that the angular momentum of a rotating body stays constant unless an external torque acts, so in flight a smaller moment of inertia gives a faster angular velocity.

The principle that the total momentum of colliding bodies is the same after a collision as before it, provided no external resultant force acts on them.

A method of coaching, based on the ecological model, in which the coach manipulates individual, task and environmental constraints to guide learners towards functional movement solutions.

The interference that occurs when several skills or variations are practised in a random order, which makes practice harder and lowers performance during practice but usually improves retention and transfer.

A skill with no obvious beginning or end, in which the end of one movement cycle is the beginning of the next, such as running, swimming or cycling.

Exercise performed at a steady, submaximal intensity without rest intervals, usually for at least 20 minutes, to develop cardiorespiratory endurance.

A recovery technique alternating short immersions in cold and warm water over several cycles, proposed to cause alternating vasoconstriction and vasodilation that pump blood through muscle.

The component of mental toughness describing perceived control over one’s emotions (emotional control) and the belief that one can influence events and outcomes through one’s own actions (life control).

The part of a homeostatic system, usually in the brain or an endocrine gland, that compares information from receptors with the set point and signals effectors to correct any difference.

A general tendency to focus on rewards, gains, deadlines and approval from others, so that behaviour is organised around external or internal controls.

A variable, other than the independent variable, that could affect the dependent variable and is therefore kept constant or monitored so that a fair test is possible.

A stressor that the individual can change, remove or influence through their own actions, such as their preparation, fitness, tactics or technique.

A training method in which distractions likely in competition are deliberately introduced into practice so that the performer learns to maintain attention despite them.

Motivation in which an activity is done as a means to an end, because of external rewards or pressure or internal pressure such as guilt, so that it feels obligatory rather than freely chosen.

A reward perceived mainly as an attempt to control behaviour, so that the person feels they act to obtain it, which tends to undermine intrinsic motivation.

An injury caused by a direct blow, in which small blood vessels are damaged and blood collects in the tissue, causing a bruise, swelling and pain.

The transfer of heat to or from the skin by a moving fluid such as air or water; heat loss increases with wind speed or movement through water.

A period of low-intensity activity after exercise that allows heart rate, breathing and blood pressure to return gradually towards resting levels and maintains venous return.

A maximal field test in which an individual runs as far as possible in 12 minutes; the distance covered is used to estimate VO₂ max.

A skill-related component of fitness: the ability to move two or more body parts together smoothly, efficiently and accurately.

The constantly changing cognitive and behavioural efforts an individual makes to manage specific external or internal demands that are appraised as taxing or exceeding their resources.

A specific, deliberate thought or action used to manage a stressor or the emotional response to it, such as making a plan, seeking advice, using self-talk or slow breathing.

The temperature of the deep tissues of the body, such as the brain, heart and abdominal organs, normally kept at about 37 ± 1 °C.

The process in which lactate from muscle is carried in the blood to the liver, converted back to glucose and returned to the blood for use as a fuel.

Disease of the heart caused by atherosclerosis of the coronary arteries, which reduces the blood supply to the heart muscle and can cause angina and myocardial infarction.

A relationship between two variables in which a change in one is associated with a change in the other; positive when both increase together, negative when one increases as the other decreases.

A number from −1 to +1, usually Pearson's r, that measures the strength and direction of the linear relationship between two variables; values near ±1 show a strong relationship.

An enzyme in muscle that breaks down phosphocreatine; its blood concentration rises when muscle fibres are damaged, so it is used as an indirect marker of muscle damage.

A supplement form of creatine that raises muscle creatine and phosphocreatine stores, improving repeated high-intensity performance and recovery between efforts; it often increases body mass.

The moment within a skill that most determines its outcome, such as the instant of release of a ball, take-off from the ground or contact between a foot, bat or racket and a ball.

The temporary link formed when a myosin head binds to a binding site on an actin filament during muscle contraction.

A research design in which every participant completes all conditions, in a randomised or balanced order, so that each participant acts as their own control.

The use of cold, such as ice packs, cold sprays or cold water, to treat an injury, mainly to reduce pain by cooling the tissue and slowing nerve conduction.

Easterbrook's theory that attention narrows as arousal rises: at low arousal irrelevant cues are taken in, at optimal arousal only relevant cues are used, and at high arousal relevant cues are missed.

An injury caused by the repeated application of force, each load too small to cause damage alone, so that microscopic damage builds up faster than the tissue can repair it.

The booklet of diagrams, equations, units, constants and statistical formulas that every candidate receives as a clean copy in each Sports, exercise and health science examination paper.

An examination question built around a stimulus of data, such as a table, graph or short description of a study, that asks candidates to read, process, interpret and evaluate that information.

The use of a false movement or cue, such as a dummy or fake, to make an opponent respond to it, so their response to the real movement is delayed by the psychological refractory period.

A positional term meaning further from the surface of the body than another structure, for example the femur is deep to the quadriceps.

The number of independent ways in which the parts of the body (joints, muscles, motor units) can move, which must be controlled and coordinated to produce a movement.

The process of losing body water, so that losses such as sweat and urine exceed intake; the resulting state of reduced body water is called hypohydration.

Muscle pain and stiffness beginning about 12–24 hours after unaccustomed or eccentric exercise, peaking at about 24–72 hours and caused by muscle damage and inflammation.

The variable that is measured in an investigation to find out how it responds to changes in the independent variable.

A downward movement of a body part in the frontal plane, such as lowering the shoulder girdle during a dip.

Modifications of a sport’s rules, equipment or playing conditions for young players according to their age and maturity, designed to reduce injury risk and suit their physical and skill development.

A dome-shaped sheet of skeletal muscle separating the thoracic and abdominal cavities, which contracts and flattens to enlarge the thoracic cavity; the main muscle of inspiration.

Slow, deep breathing in which the diaphragm, not the chest and shoulders, does most of the work, so the abdomen rises on inhalation; it lowers heart rate and arousal.

The shaft of a long bone: a tube of compact bone surrounding the medullary cavity, which contains yellow bone marrow.

The phase of the cardiac cycle in which heart muscle relaxes and the chambers fill with blood, with the semilunar valves closed and the atrioventricular valves open.

The lowest pressure in the arteries, reached while the ventricles relax and fill; about 80 mmHg at rest in a healthy young adult.

The passive net movement of molecules from a region of higher concentration or partial pressure to a region of lower concentration, needing no energy.

A skill with a clear beginning and a clear end, usually performed quickly, such as a basketball free throw, a golf drive or a penalty kick.

A maladaptive coping strategy in which an individual reduces or stops their effort to deal with a stressor or reach a goal, either mentally (not thinking about the task) or behaviourally (giving up).

An injury in which the articulating surfaces of the bones in a joint are forced completely out of contact, usually stretching or tearing the joint capsule and ligaments.

The shortest straight-line distance between the start and finish positions of a body, in a stated direction; a vector measured in metres (m).

A positional term meaning further from the trunk, or from the point where a limb attaches to the trunk, than another structure, for example the ankle is distal to the knee.

The total length of the path travelled by a body, regardless of direction; a scalar measured in metres (m).

The movement of attention away from task-relevant cues to information irrelevant to the task, so that concentration is lost.

A negative form of stress in which a demand is perceived as threatening or overwhelming, producing fear, worry and helplessness that usually harm performance and well-being.

Practice with rest intervals or other activities between attempts or blocks, allowing recovery and mental rehearsal; suited to beginners and complex or demanding skills.

A non-specific goal in which the individual is simply asked to try as hard as possible, with no defined target or standard of performance.

The most likely, habitual response of a performer in a situation; increased arousal makes it more likely to occur, whether it is correct or incorrect.

A movement at the ankle in the sagittal plane that brings the top of the foot towards the shin, decreasing the angle at the front of the ankle.

Travelling closely behind another competitor or vehicle, in their wake, to reduce drag and the energy needed to maintain speed; also called slipstreaming.

The force exerted by a fluid that resists the motion of a body through it, acting opposite to the body's motion relative to the fluid; also called fluid resistance.

A theory proposing a positive linear relationship between arousal and performance, in which increased arousal makes the dominant response more likely, improving well-learned skills and impairing new ones.

Withdrawal from a sport or physical activity before a person has reached their potential or chosen to stop for positive reasons, often linked to low perceived ability, low enjoyment or an ego-involving environment.

The friction between two surfaces that are sliding relative to each other, $F_\text{f} = \mu_\text{d} F_\text{N}$; usually smaller than limiting static friction.

An inward collapse of the knee during landing, cutting or squatting, combining hip adduction, hip internal rotation and knee abduction, which increases load on the ACL and the kneecap.

A stretching method in which a joint is moved actively and in a controlled way through its full range of motion, repeatedly, often using movements that resemble the sport.

A theory treating the body as a complex system of many interacting parts whose coordinated movement patterns emerge through self-organisation under individual, task and environmental constraints.

An isotonic contraction in which the muscle lengthens while producing tension, because the load is greater than the muscle force; it controls or brakes a movement.

A force whose line of action does not pass through the centre of mass of a body, producing rotation (angular motion) as well as linear motion.

A theory of motor learning combining ecological psychology and dynamical systems theory, explaining skilled movement as emerging from performer–environment interaction guided by directly perceived information.

A model of motor learning in which movement emerges from the interaction of performer, task and environment, and learning is the improving coupling of perception and action without stored programmes.

A theory of perception and action, developed from Gibson's work, proposing that performers perceive information in the environment directly and use it to guide action without stored representations.

A muscle or gland that receives a signal from a control centre and produces a response that changes a regulated variable.

The part of the peripheral nervous system that carries nerve impulses from the central nervous system to effectors (muscles and glands); also called the motor division.

The force applied to a lever to make it rotate; in the human body, the force produced by a contracting muscle at its insertion.

The perpendicular distance from the fulcrum of a lever to the line of action of the effort.

A motivational climate in which success is defined as winning and outperforming others, with public comparison, recognition mainly for the most able, rivalry between teammates and punishment of mistakes; also called a performance climate.

A goal orientation in which a person judges success and competence in a norm-referenced way, by outperforming others or performing equally well with less effort.

Defensive behaviour, such as blaming others, rejecting feedback or withdrawing effort, that a person uses to protect their self-esteem and the appearance of ability when it is challenged.

The energy stored in a body that has been stretched, compressed or bent, released as it returns to its original shape, as in a vaulting pole, tendon or trampoline bed.

A mineral that dissolves in body fluids to form charged ions, such as sodium, potassium, chloride, calcium and magnesium, which control fluid balance and nerve and muscle function.

The recording of the electrical activity produced by muscle fibres when they are activated, usually with electrodes on the skin, to show when a muscle is active and how strongly.

A series of proteins on the inner membrane of the mitochondria that uses hydrogen from the Krebs cycle to resynthesise most of the ATP in aerobic metabolism, with oxygen accepting the hydrogen to form water.

An upward movement of a body part in the frontal plane, such as raising the shoulder girdle in a shrug.

Raising an injured limb above the level of the heart so that gravity helps fluid drain away from the injured area and reduces swelling.

Coping strategies that do not change the stressor but regulate the emotional response to it, such as relaxation, self-talk, reframing and seeking emotional social support.

The opposite pole of neuroticism, describing an individual’s tendency to stay calm and maintain emotional balance in stressful or demanding situations.

A ductless gland that secretes hormones directly into the bloodstream, such as the pituitary, thyroid, adrenal glands, pancreas, ovaries and testes.

The body's endocrine glands and the hormones they release into the blood, which together regulate processes such as metabolism, growth, water balance and reproduction.

The capacity to do work, measured in joules (J); it can be transformed from one form to another, such as kinetic, potential, chemical or thermal, but not created or destroyed.

The dietary energy left for the body's other functions after the energy cost of exercise is subtracted, per kilogram of fat-free mass per day: (energy intake − exercise energy expenditure) ÷ fat-free mass.

The relationship between energy intake and energy expenditure; when the two are equal, body energy stores and body mass stay stable.

The relative contributions of the phosphagen, glycolytic and oxidative systems to ATP resynthesis, which change with the intensity and duration of an activity; all three systems contribute at all times.

The total energy used by the body over a period, made up of basal metabolic rate, the thermic effect of food and the energy used in physical activity.

The total chemical energy taken into the body in food and drink over a period, from carbohydrate, protein, fat and alcohol, usually in kJ or kcal per day.

A series of chemical reactions in the body that releases energy from a fuel and uses it to resynthesise ATP from ADP and inorganic phosphate: the phosphagen, glycolytic or oxidative system.

Features of the surroundings that shape movement, either physical (surface, temperature, wind, light) or sociocultural (family, peers, culture, access to facilities).

A hormone released by the adrenal medulla in response to sympathetic stimulation, which raises heart rate, stroke volume, blood pressure and blood glucose; also called adrenaline.

The expanded end of a long bone, made of spongy bone containing red marrow inside a thin shell of compact bone, covered by articular cartilage where it forms a joint.

The scientific study and design of equipment, tasks and environments to fit the people who use them, in order to improve efficiency, comfort and safety.

Lines drawn above and below a plotted mean to show the variability or uncertainty in the data, usually ±1 standard deviation, ±1 standard error or the range.

A hormone produced mainly by the kidneys, in response to low blood oxygen and stimulated by testosterone, which increases red blood cell production in the bone marrow.

An amino acid the body cannot make in sufficient amounts, so it must be supplied by the diet; nine of the twenty amino acids are essential.

The state of normal body water content, within the small daily variation of about 1% of body mass found in a healthy person.

A positive form of stress in which a demand is perceived as a challenge or opportunity, producing excitement and energy that can improve motivation and performance.

Heat loss as water, mainly sweat, changes from liquid to vapour on the skin or in the airways; the main route of heat loss during exercise and the only one when air is hotter than skin.

A movement of the foot in the frontal plane that turns the sole outwards, away from the midline of the body.

The volume of oxygen consumed after exercise above the resting level, used to return the body to its pre-exercise state; it has a fast and a slow component.

Physical activity that is planned, structured and repetitive, done to improve or maintain one or more components of fitness or health.

The planning of an individualised exercise programme, specifying frequency, intensity, time and type of exercise and how they progress, based on a person's health, fitness, goals and preferences.

Microscopic damage to muscle fibres and connective tissue after unaccustomed or eccentric exercise, causing temporary strength loss, inflammation, raised creatine kinase and delayed-onset muscle soreness.

The maximum volume of air that can be breathed out after a normal expiration; about 1.2 L in a young adult man.

A longer written answer worth several marks, usually to a discuss, evaluate or explain question, in which linked points, evidence and a reasoned judgment are developed in continuous prose.

A movement in the sagittal plane that increases the angle between the bones at a joint, returning a body part towards the anatomical position, such as straightening the knee.

A visual or auditory stimulus in the environment, such as crowd noise, cameras or an opponent's comments, that draws attention away from task-relevant cues.

Attention directed outside the body, to cues in the environment or to the intended effect of a movement, such as the flight of the ball or the target.

Imagery from a third-person perspective, in which the performer watches themselves performing the skill as if on video or from the stands.

The least self-determined type of extrinsic motivation, in which behaviour is controlled by external rewards, punishments or demands and feels like having little or no choice (“I must”).

A feature of the environment in which an individual exercises or competes that increases the risk of injury, such as equipment, surface, weather, rules, opponents or coaching.

A skill whose timing and rate are controlled by the environment, such as an opponent, the ball or a starting signal, for example receiving a volleyball serve.

The fluid outside the cells, about one-third of total body water, made up mainly of interstitial fluid and blood plasma, in which sodium and chloride are the main ions.

A Big Five trait describing the extent to which an individual draws energy from interacting with other people and seeks stimulation, being sociable, talkative, assertive and energetic.

Control of the heart from outside it, by sympathetic and parasympathetic nerves and by hormones such as epinephrine, which change the rate of SA node firing and the force of contraction.

Feedback from an outside source, such as a coach, team-mate, video or timing system, added to what the performer senses for themselves.

Motivation to take part in an activity as a means to an end, for an outcome separate from the activity such as a reward, praise, status, avoiding punishment or a health benefit.

Anxiety symptoms that a performer interprets as helpful to performance, as a sign of readiness; the opposite interpretation, as harmful to performance, is debilitative anxiety.

A form of continuous training in which speed and intensity are varied, often over varied terrain, so that both aerobic and anaerobic energy systems are stressed.

Sheets of collagen-rich connective tissue that surround and separate muscles and muscle groups, allow them to slide past one another and help transmit force between them.

A bundle of skeletal muscle fibres wrapped in a layer of connective tissue called the perimysium; many fascicles make up a whole muscle.

The first 2–3 minutes of recovery, when oxygen consumption falls rapidly as phosphocreatine and ATP are resynthesised and the oxygen stores of myoglobin and blood are restored.

The mass of the body excluding all fat, made up of muscle, bone, organs, connective tissue and water; often called lean body mass.

A reduction in the maximal force or power that muscles can produce, or a rise in the perceived effort needed to maintain a given output, caused by exercise and reversed by rest.

A chain of carbon atoms with hydrogen atoms attached and an acid group at one end; saturated fatty acids have only single carbon–carbon bonds, unsaturated ones have one or more double bonds.

Information received by a performer about a movement or its outcome, during or after the movement, which can be used to detect and correct errors.

An earlier model describing three interrelated conditions in female athletes: low energy availability (with or without disordered eating), menstrual dysfunction and low bone mineral density.

A protein that stores iron in the body, mainly in the liver; the concentration of ferritin in the blood (serum ferritin) is used as a measure of iron stores.

A tough type of cartilage containing dense bundles of collagen fibres that resists compression and tension, forming the menisci, intervertebral discs and pubic symphysis.

A joint in which the bones are held together by dense fibrous connective tissue without a joint cavity, allowing no or almost no movement, such as the sutures of the skull.

A skill that uses small muscle groups and small, precise movements, often needing high hand–eye coordination, for example an archery release or a snooker shot.

A lever in which the fulcrum lies between the effort and the load, such as the head nodding at the atlanto-occipital joint; its mechanical advantage can be above, equal to or below 1.

The ability to meet the physical demands of a task or environment, such as daily life, an occupation or a sport, without undue fatigue.

A planning aid for applying overload by adjusting the frequency, intensity, time (duration) and type of exercise.

A muscle that contracts, usually isometrically, to stabilise the bone to which the agonist is attached, so that the agonist moves only the intended bone.

The range of motion available at a joint or a group of joints, determined by joint structure and the extensibility of muscles, tendons and ligaments.

A planned programme of stretching exercises that aims to increase or maintain the range of motion at a joint, using static, dynamic or PNF techniques.

A movement in the sagittal plane that decreases the angle between the bones at a joint, such as bending the knee or raising the arm forwards at the shoulder.

A substance, either a liquid or a gas, that can flow and takes the shape of its container; in sport the main fluids are air and water.

The first phase of the menstrual cycle, from the start of menstruation to ovulation, in which oestrogen rises as ovarian follicles develop while progesterone stays low.

The final phase of a discrete skill, in which the body keeps moving after release or contact, ensuring maximum speed at contact and slowing the limbs gradually to reduce peak forces.

A push or pull acting on a body that can change its state of motion or its shape; a vector measured in newtons (N).

A measuring platform in or on the floor that records the ground reaction force applied to it many times per second, used to analyse jumping, landing, running, balance and gait.

The phase of a movement in which the muscles contract to generate the force that moves the body or an object, usually sequencing joint actions from large proximal to small distal segments.

A graph of the force acting on a body against time, usually recorded with a force plate, in which the area under the curve equals the impulse.

Drag caused by the difference between the high pressure in front of a body and the low pressure in the turbulent wake behind it; it depends on shape and frontal area. Also called pressure drag.

A break or crack in a bone, caused by a force greater than the bone can withstand or by repeated loading; classified as open or closed and by the pattern of the break.

The principle that the more the ventricle is filled and stretched during diastole, the more forcefully it contracts, so greater venous return produces a greater stroke volume.

A diagram of a single body showing all the external forces acting on it as labelled arrows from their points of application, with lengths roughly proportional to their size.

A force acting parallel to two surfaces in contact that opposes their relative motion, or the tendency of one surface to slide over the other.

An axis running horizontally from side to side through a joint or the body; rotation about it occurs in the sagittal plane, as in flexion, extension and a somersault.

A vertical plane running from side to side that divides the body into front and back parts, also called the coronal plane; abduction and adduction occur in it, about the sagittal axis.

The freezing of body tissue, usually of the fingers, toes, ears or nose, when skin temperature falls below freezing; severe frostbite can cause permanent tissue loss.

The fixed point or axis about which a lever rotates; in the human body, usually a joint.

The principle that imagining a movement uses many of the same brain areas and processes as physically performing it, so imagery that closely matches real performance is more effective.

A planned, short-term increase in training load that causes a temporary fall in performance lasting days to about two weeks, followed by improved performance after recovery.

The systematic analysis of walking or running, describing the stance and swing phases, joint movements, forces and timing to identify abnormal patterns, guide treatment or improve performance.

An intervention that changes how a person walks or runs, usually using real-time feedback and practice, to reduce the load on an injured or at-risk tissue.

An objective measure of arousal based on the electrical conductance of the skin, which increases as sweat gland activity rises with sympathetic nervous system activation.

The movement of oxygen and carbon dioxide by diffusion between the alveoli and the blood, and between the blood and the tissues, down partial pressure gradients.

The absence of digestive symptoms such as nausea, bloating, cramps and diarrhoea during exercise; it depends on what and when an athlete eats and drinks, exercise intensity and individual tolerance.

A combination of linear and angular motion, as in running or cycling, where rotation of the limbs about the joints produces translation of the whole body.

A stored, abstract movement pattern for a class of actions, with fixed sequence and relative timing, adapted to each situation by setting parameters such as force, speed and direction.

A synovial joint, also called a plane joint, with nearly flat surfaces that slide over one another in small movements, such as the joints between the carpals.

A hormone released by the alpha cells of the pancreas when blood glucose is low, which raises it by stimulating glycogenolysis and gluconeogenesis in the liver.

The production of new glucose in the liver from non-carbohydrate sources such as lactate, glycerol and amino acids, stimulated by glucagon.

A monosaccharide that is the main carbohydrate in the blood and the form in which carbohydrate is taken up and used by cells for energy.

A ranking of carbohydrate foods from 0 to 100 by how much and how quickly they raise blood glucose compared with the same amount of glucose.

A branched polysaccharide made of many glucose units; the form in which carbohydrate is stored in skeletal muscle (about 500 g) and the liver (about 80 g).

The fall of glycogen stores in working muscles and the liver to very low levels during prolonged exercise, which slows ATP resynthesis from carbohydrate and forces a lower intensity.

The breakdown of glycogen stored in the liver or muscle into glucose, stimulated by glucagon and epinephrine.

The energy system that resynthesises ATP anaerobically by breaking down glucose or glycogen to pyruvate in the sarcoplasm, producing lactate and hydrogen ions when pyruvate forms faster than it is oxidised.

The regular review and modification of goals, by raising, lowering, re-timing or replacing them, in response to progress, setbacks or changed circumstances, so that they stay challenging, achievable and meaningful.

A mini-theory of self-determination theory distinguishing intrinsic goals (growth, relationships, community, health) from extrinsic goals (wealth, fame, image), and linking intrinsic goals to greater well-being.

A sequence of progressively harder short-term goals, arranged like the rungs of a ladder, that lead step by step to a long-term goal.

A psychological skill in which an individual sets specific targets to work towards, in order to direct attention, increase motivation and improve performance or behaviour in sport, exercise or health.

The finding that individuals who set harder goals tend to perform better but feel less satisfied with their performance, because a harder goal raises the standard needed for satisfaction; elite athletes may feel deflated after success.

A proprioceptor at the junction of a muscle and its tendon that detects tension in the muscle; very high tension causes the muscle to relax, protecting it.

A protractor-like instrument with two arms, centred over the axis of a joint, used to measure the angle of the joint or its range of motion in degrees.

The proposal that coping is most effective when the strategy matches the controllability of the stressor: problem-focused coping for controllable stressors, emotion-focused coping for uncontrollable ones.

A test in which exercise intensity rises in stages until exhaustion, used to measure VO₂ max, the blood lactate response or maximum heart rate.

A stepwise programme after concussion in which activity progresses from symptom-limited daily activity through aerobic, sport-specific and non-contact training to full contact and competition, each step usually lasting at least 24 hours.

The energy a body possesses because of its height above a reference level, equal to $mgh$; measured in joules (J).

A skill that uses large muscle groups and large movements, where precision is less important, for example a shot put or a tackle.

The force exerted by the ground on a body in contact with it, equal in size and opposite in direction to the force the body applies to the ground.

A hormone released by the anterior pituitary gland, mainly during slow-wave sleep and exercise, that stimulates protein synthesis, tissue growth and repair, and fat breakdown.

A layer of cartilage near each end of a long bone in children and adolescents where the bone grows in length; it is weaker than surrounding bone and ligaments until it closes.

Information given to a learner to help them understand and perform a skill, in visual, verbal, manual or mechanical form.

The community of trillions of microorganisms, mainly bacteria, living in the digestive tract, mostly in the large intestine, together with their genes; it affects nutrient availability, immunity and health.

The lighter region in the centre of the A band containing only myosin filaments, which shortens and may disappear during contraction.

The percentage of the blood volume made up of red blood cells, typically higher in men than in women; raising it increases the oxygen-carrying capacity of the blood.

The iron-containing protein in red blood cells that binds reversibly with oxygen, loading it in the lungs and releasing it in the tissues; each molecule carries up to four oxygen molecules.

The components of fitness associated with good health and a reduced risk of disease: cardiorespiratory endurance, muscular strength, muscular endurance, flexibility and body composition.

The number of times the heart beats per minute, measured in beats min⁻¹; typically 60–80 beats min⁻¹ at rest in an adult.

The difference between an individual's maximum heart rate and resting heart rate, representing the range of heart rate available for exercise.

The variation in the time interval between successive heartbeats, reflecting sympathetic and parasympathetic balance; a fall below an individual's normal resting value suggests incomplete recovery.

Flaps of tissue between the chambers of the heart and at the exits of the ventricles that open and close in response to pressure differences, so blood flows in one direction only.

The adaptations to repeated exercise in hot conditions over about 1–2 weeks, including earlier and greater sweating, more dilute sweat, larger plasma volume and lower heart rate and core temperature at a given workload.

A heat illness in which the cardiovascular system cannot meet the demands of muscles and skin, usually with dehydration, causing fatigue, dizziness, nausea and sometimes collapse, with core temperature usually below 40 °C.

A life-threatening failure of thermoregulation in which core temperature rises above about 40 °C with central nervous system dysfunction such as confusion or collapse; it needs immediate whole-body cooling.

The vertical distance between the point at which a projectile is released and the level at which it lands; releasing above the landing level lowers the best angle of release.

The proportion of the variation in a trait within a population that is explained by genetic differences between individuals; it describes a population, not one person.

A principle stating that choice reaction time increases as the number of possible stimulus–response alternatives increases, rising by a roughly constant amount each time the number of choices doubles.

Repeated bouts of high-intensity exercise, typically above 80% of maximum heart rate, lasting seconds to several minutes, separated by rest or low-intensity exercise.

A uniaxial synovial joint in which a convex surface fits into a concave one, allowing only flexion and extension, such as the elbow and knee.

The self-regulating processes that keep the body's internal environment relatively stable, within narrow limits, so that cells and organs function optimally despite internal and external changes.

A movement in the transverse plane that takes a limb, raised to the horizontal, backwards away from the midline, as in a discus wind-up; also called horizontal abduction.

A movement in the transverse plane that brings a limb, raised to the horizontal, forwards and across towards the midline, as in a chest press; also called horizontal adduction.

A chemical messenger released by an endocrine gland into the blood, which carries it to target cells elsewhere in the body, where it changes their activity.

Extension of a joint beyond the anatomical position, such as arching the lower back in a back walkover or swinging the arm behind the body.

A range of motion at several joints well beyond the normal range, which can help in sports such as gymnastics but may reduce joint stability and increase the risk of sprains and dislocations.

An abnormally high concentration of sodium in the blood plasma, above about 145 mmol per litre, usually caused by losing water with relatively little sodium, as in heavy sweating without drinking.

A resting blood pressure that is persistently at or above 140/90 mmHg in WHO and many European guidelines, or 130/80 mmHg in the 2017 American guideline; also called high blood pressure.

An abnormally high core body temperature resulting from heat production and gain exceeding heat loss; near about 40 °C during exercise it causes fatigue and risks heat illness.

A drink with a higher osmolarity than blood plasma, usually more than about 8% carbohydrate, which supplies energy but empties from the stomach and is absorbed more slowly.

An increase in the size of a muscle caused by an increase in the cross-sectional area of its fibres, mainly through the synthesis of more contractile proteins and myofibrils.

An abnormally low blood glucose concentration (below about 3.9 mmol per litre); in prolonged exercise it follows liver glycogen depletion and contributes to central fatigue.

The state of having less body water than normal, resulting from dehydration; it raises heart rate and core temperature during exercise.

An abnormally low concentration of sodium in the blood plasma, below 135 mmol per litre, most often caused in sport by drinking more hypotonic fluid than is lost during prolonged exercise.

A region at the base of the brain that links the nervous and endocrine systems; it controls body temperature, thirst and water balance, makes ADH and controls the pituitary gland.

A fall in core temperature below 35 °C, when heat loss exceeds heat production, causing shivering, then confusion, loss of coordination and, if it continues, unconsciousness and death.

A testable prediction of the relationship between variables, based on scientific theory, that the data of an investigation can support or fail to support.

A drink with a lower osmolarity than blood plasma, such as water or a dilute sports drink, which replaces fluid quickly but supplies little carbohydrate.

A shortage of oxygen reaching the body's tissues; at altitude it results from the lower partial pressure of oxygen, which reduces the saturation of haemoglobin with oxygen.

In catastrophe theory, the finding that after a performance collapse, arousal must fall well below the level at which the collapse occurred before performance can recover.

The light band of a sarcomere containing only actin filaments, spanning a Z line, which shortens during contraction.

A pattern of mood scores on the Profile of Mood States in which an athlete scores below the population average on tension, depression, anger, fatigue and confusion and above average on vigour.

An autonomous type of extrinsic motivation in which a person values the outcome of a behaviour and wants to do it, but still as a means to an end (“I want to”).

A process of creating or recreating an experience in the mind using several senses, such as sight, sound and the feel of movement, without actual perception; also called mental rehearsal or visualisation.

A written plan that guides an imagery session, describing the setting, the senses, emotions, perspective and timing of the skill to be imagined, often recorded and listened to.

The ability of the immune system to detect and destroy pathogens and abnormal cells, through physical barriers, white blood cells and antibodies.

A general tendency to feel that outcomes are beyond one’s control, marked by anxiety about competence and a lack of intentional action, which leads to amotivation.

The product of the average force acting on a body and the time for which it acts, $J = F\Delta t$; equal to the change in momentum and measured in N s.

The principle that the impulse applied to a body equals its change in momentum ($F\Delta t = \Delta p$), so a greater impulse produces a greater change in momentum.

A situational factor in need achievement theory: how much pride or satisfaction success at a task would bring, which is greater when success is less likely (Is = 1 − Ps).

The specific action or situation at the moment an injury occurs, such as a landing, tackle or sudden change of direction, which provides the load that exceeds a tissue’s capacity.

The variable that the investigator deliberately changes or selects in an investigation, in order to find out its effect on the dependent variable.

Characteristics of the performer that shape movement, either structural (height, limb length, body mass) or functional (fitness, skill, motivation, emotions, fatigue).

A band of pre-competition anxiety or emotional intensity within which an individual athlete performs best; the zone may be low, moderate or high and differs between athletes.

A training principle stating that a programme should be designed for the needs, goals, abilities, health and responses of the individual rather than copied from someone else.

The resistance of a body to a change in its state of motion, whether at rest or moving at constant velocity; directly proportional to the body’s mass.

A small wearable device containing an accelerometer and a gyroscope that measures the acceleration and rotation of the body segment it is attached to, allowing movement analysis outside the laboratory.

A positional term meaning away from the head or lower down the body than another structure, for example the knee is inferior to the hip.

The body’s immediate protective response to tissue damage, in which blood vessels dilate and become more permeable, causing redness, heat, swelling, pain and loss of function; the first phase of healing.

A model of motor control and learning describing how information is received, interpreted, used to select a response from memory and sent to the muscles, with feedback adjusting later responses.

A reward or piece of feedback perceived mainly as information about one’s competence, given without pressure, which tends to maintain or increase intrinsic motivation.

A participant's voluntary agreement to take part in research, given after being told the purpose, procedures, risks and the right to withdraw at any time without giving a reason.

Damage to the body’s tissues that occurs when the force applied to a tissue exceeds what it can withstand, causing pain and loss of function.

Any strategy that lowers the likelihood or severity of injury, by reducing abnormal forces on body tissues or by increasing the body’s capacity to absorb and tolerate force.

A phosphate ion released when ATP and phosphocreatine are broken down; its accumulation in high-intensity exercise reduces cross-bridge force and calcium release, causing peripheral fatigue.

The maximum volume of air that can be breathed in after a normal inspiration; about 3 L in a young adult man.

Self-talk that directs attention to the technical or tactical aspects of a skill, such as the cue "high elbow" in swimming; most effective for fine and newly learned skills.

A hormone released by the beta cells of the pancreas when blood glucose is high, which lowers it by increasing glucose uptake into muscle, liver and fat cells and its storage as glycogen.

A reduced response of muscle, liver and fat cells to insulin, so that more insulin is needed to lower blood glucose; insulin sensitivity is the opposite.

The most self-determined type of extrinsic motivation, in which the reasons for a behaviour fit fully with the person’s values and identity, although it is still done for a separate outcome.

The view that behaviour results from an interaction between an individual’s personality traits and the situation or environment, summarised as B = f(P × E).

Two layers of muscle between the ribs: the external intercostals lift the ribs up and out in inspiration, and the internal intercostals pull them down and in during forced expiration.

A positional term describing a structure that lies between a more medial and a more lateral structure, for example the clavicle lies between the sternum and the shoulder joint.

A thought, feeling or sensation within the performer, negative or unrelated to the task, that draws attention away from relevant cues, such as worry about the outcome.

Attention directed inside the body, to thoughts, feelings, mental images or the movements of one's own body parts.

Imagery from a first-person perspective, in which the performer sees the scene as through their own eyes while performing the skill.

A characteristic of the individual that increases the risk of injury, such as age, sex, previous injury, fitness, fatigue, anatomy or technique; also called an intrinsic risk factor.

A neuron within the central nervous system that links sensory neurons to motor neurons and allows information to be integrated.

The difference between the upper quartile and the lower quartile of an ordered data set; the range of the middle 50% of the values, unaffected by extreme values.

Training that alternates periods of work with periods of rest or low-intensity recovery, with work and rest durations chosen to target a particular energy system.

The fluid inside the body's cells, about two-thirds of total body water, in which potassium is the main positive ion.

Control of the heartbeat from within the heart by its conduction system (SA node, AV node, bundle of His and Purkinje fibres), without input from nerves or hormones.

Feedback that comes from within the performer through the senses, especially proprioceptors, during or after a movement, such as the feel of a well-struck ball.

Motivation to take part in an activity for its own sake, for the enjoyment, interest and satisfaction that the activity itself provides.

A controlled type of extrinsic motivation in which behaviour is driven by internal pressures such as guilt, shame or the need to protect self-esteem (“I should”).

The opposite pole of extraversion, describing an individual who finds social interaction draining and prefers quieter, less stimulating settings; it is not the same as shyness.

A movement of the foot in the frontal plane that turns the sole inwards, towards the midline of the body.

A theory that performance improves as arousal increases up to an optimal, moderate level, after which further increases in arousal cause performance to decline.

A mineral that forms part of haemoglobin, myoglobin and some enzymes of the oxidative system, allowing oxygen to be transported, stored and used to resynthesise ATP aerobically.

A muscle contraction in which the muscle changes length at a constant speed throughout the range of movement, usually produced on an isokinetic dynamometer that matches its resistance to the force applied.

A muscle contraction in which tension is produced but the muscle length does not change and no joint movement occurs, because the muscle force equals the opposing force.

A muscle contraction in which the muscle changes length and moves a joint while producing tension; it is either concentric (shortening) or eccentric (lengthening).

A drink with about the same osmolarity as blood plasma, typically containing 6–8% carbohydrate and some sodium, which supplies both fluid and fuel and is absorbed quickly.

A model of the relationship between exercise load and the risk of upper respiratory tract infection: risk is lower with regular moderate exercise than with inactivity, but higher with very prolonged, intense exercise.

A temporary disturbance of sleep, alertness, digestion and performance after rapid travel across three or more time zones, caused by a mismatch between the body clock and local time.

A sleeve of dense fibrous connective tissue that surrounds a synovial joint and attaches to the bones on either side, enclosing the joint cavity and holding the bones together.

A proprioceptor in the capsule and ligaments of a joint that detects the joint's angle, its movement and the pressure on it.

The ability of a joint to keep its articulating bones in their correct position and to resist displacement or injury during movement.

A method of calculating target heart rate by adding a chosen percentage of heart rate reserve to resting heart rate: target HR = HRrest + intensity × (HRmax − HRrest).

Imagery of the feel of a movement, including muscle tension, body position, force and rhythm, built from sensations of the muscles and joints.

The energy a body possesses because of its motion, equal to $\tfrac{1}{2}mv^2$; measured in joules (J).

Feedback about the quality or pattern of a movement (the technique) rather than its outcome, for example the position of the elbow at release.

Extrinsic feedback about the outcome of a movement, such as the score, time, distance or whether a shot was successful.

A cycle of reactions in the mitochondria that breaks down acetyl coenzyme A from carbohydrate, fat or protein, releasing carbon dioxide and hydrogen for the electron transport chain.

A cut or tear in the skin, often deep and irregular, caused by a sharp object or by a blunt impact that splits the skin.

A compound formed from pyruvate when glycolysis is rapid; it is a fuel that is oxidised in muscle and the heart or converted to glucose in the liver, not the cause of muscle soreness.

The removal of lactate from the blood, mainly by oxidation in muscle fibres and the heart and by conversion to glucose in the liver through the Cori cycle.

The highest exercise intensity at which lactate is removed from the blood at the same rate as it is produced; above it, blood lactate concentration rises rapidly.

Smooth flow of a fluid in parallel layers that slide past each other without mixing; it occurs at low speeds and around smooth, streamlined shapes.

A positional term meaning further from the midline of the body than another structure, for example the fibula is lateral to the tibia.

Pain on the outside of the elbow at the attachment of the wrist extensor muscles, caused by repeated overloading of their common tendon, as in a faulty tennis backhand; also called tennis elbow.

A state in which an individual, after repeated failure or uncontrollable experiences, believes that their actions cannot change future outcomes and therefore stops trying.

A relatively permanent change in behaviour, or in the capability to perform a skill, brought about by practice and experience.

A self-referenced goal that focuses on improving one’s own performance or the technique and strategy used, rather than on beating others; it includes performance goals and process goals.

A rigid bar that rotates about a fixed point (the fulcrum) when a force (the effort) is applied, in order to move or overcome another force (the load).

The component of the force exerted by a fluid on a moving body that acts perpendicular to the direction of the fluid flow; it can act upwards, downwards or sideways.

A band of dense, regular, collagen-rich connective tissue that joins bone to bone at a joint, stabilising the joint and limiting excessive movement.

A feature of an investigation that restricts how far its conclusion can be applied, such as the range of data collected, the sample or system studied, or the assumptions made.

An imaginary vertical line passing through the centre of mass towards the ground, showing the line along which weight acts.

Movement in which all parts of a body travel the same distance in the same direction in the same time, along a straight or curved path; also called translation.

A coach-centred approach to teaching motor skills, based on the information processing model, in which a correct technique is demonstrated, broken down and repeated in progressive drills with corrective feedback.

A macronutrient made mainly of carbon and hydrogen with little oxygen, insoluble in water; includes triglycerides (fats and oils), phospholipids and steroids, and provides about 37 kJ per gram.

An altitude training strategy in which athletes live or sleep at moderate or simulated altitude to stimulate red blood cell production but train at low altitude to maintain training intensity.

The force that a lever acts against, also called the resistance; in the body, the weight of the body segment and of any object held, moved or struck.

The perpendicular distance from the fulcrum of a lever to the line of action of the load.

The relationship between the load placed on a tissue and its capacity to tolerate it; injury occurs when load exceeds capacity, suddenly or because repeated loading without recovery lowers capacity.

The dimension of attribution describing whether the cause of an outcome is seen as internal (within the individual) or external (outside the individual); also called locus of causality.

The dimension of attribution describing whether the cause of an outcome is seen as stable (unlikely to change over time) or unstable (likely to change); it affects expectations of future success.

A bone that is longer than it is wide, with a shaft (diaphysis) and two ends (epiphyses), such as the femur or humerus; long bones act as levers for movement.

A goal to be achieved over a long period, usually months or years, that gives overall direction to training or behaviour change.

The memory store of well-learned information and motor programmes, with almost unlimited capacity and duration, from which past experiences are retrieved to select responses.

An axis running vertically from head to toe, or along the length of a limb; rotation about it occurs in the transverse plane, as in a pirouette or medial rotation.

A state in which energy intake is insufficient to cover the energy cost of exercise and still support the physiological functions needed for optimal health; below about 30 kcal per kg fat-free mass per day is clinically low.

The phase of the menstrual cycle after ovulation, lasting about 14 days, in which the corpus luteum secretes progesterone and oestrogen, so both hormones are relatively high.

The line at the centre of a sarcomere that holds the myosin filaments in place and towards which actin is pulled during contraction.

The longest cycle of a periodised programme, usually a season or a year, built around the main competitions and divided into preparatory, competition and transition phases.

A nutrient needed in large amounts (grams per day) that provides energy and materials for growth and repair; the three macronutrients are carbohydrates, proteins and lipids.

The deflection of a spinning object from its path, caused by a pressure difference across it; the force acts perpendicular to the direction of travel, towards the side whose surface moves with the airflow.

Coping strategies that may reduce distress in the short term but are associated with poorer performance, well-being or goal attainment over time, such as disengagement, venting and self-blame.

A relatively stable personality characteristic that can nevertheless be changed or developed over time through experience, training and the environment.

The amount of matter in a body, which does not change with location or gravity; a scalar measured in kilograms (kg).

Practice with no rest intervals, or very short ones, between attempts or blocks, suited to simple skills and fit, motivated, experienced performers.

A motivational climate in which success is defined as effort, learning and personal or team improvement, cooperation is encouraged and mistakes are treated as part of learning; also called a task-involving climate.

A response to failure in which an individual attributes the failure to changeable, controllable causes, keeps positive expectations and increases effort and persistence.

The highest constant exercise intensity at which blood lactate concentration stays stable over time, because lactate production and clearance are balanced.

The highest heart rate an individual can reach during maximal exercise; it falls with age and is often estimated as 220 minus age in beats min⁻¹.

The sum of all the values in a data set divided by the number of values; the most common measure of the typical value of a continuous variable.

The ratio of the effort arm to the load arm of a lever; a value greater than 1 means a load can be moved with a smaller effort.

The situation in which the effort arm of a lever is shorter than the load arm (mechanical advantage below 1), so a larger effort is needed but the load moves faster and through a greater range.

The process by which respiratory muscles change the volume of the thoracic cavity, creating pressure differences between the lungs and the atmosphere that move air in and out.

A positional term meaning closer to the midline of the body than another structure, for example the ulna is medial to the radius in the anatomical position.

Pain along the inner border of the lower half of the tibia caused by repeated loading in running and jumping, thought to involve stress reactions in the bone; also called shin splints.

The lowest part of the brainstem, which contains the cardiovascular and respiratory control centres that regulate heart rate and breathing without conscious thought.

A hormone released by the pineal gland in darkness, mainly in the evening, that promotes sleep and helps synchronise the circadian rhythm; light suppresses its release.

A crescent-shaped pad of fibrocartilage between the articular surfaces of a joint, such as the knee, that deepens the joint, absorbs shock and spreads load.

The recurring cycle of hormone-controlled changes in the ovaries and uterus that prepares the body for a possible pregnancy, counted from the first day of menstruation and lasting about 21–35 days.

The cognitive rehearsal of a skill without physical movement, in which the performer imagines performing the skill in order to learn it or improve its performance.

An aspect of personality that partly explains how individuals manage challenging and pressurised situations, including how they appraise challenges and remain committed, confident and in control under pressure.

A medium-length training cycle, typically 3–6 weeks, with a specific training goal; several mesocycles make up each phase of a macrocycle.

A unit of exercise intensity expressing energy use as a multiple of resting metabolic rate; 1 MET is about 3.5 mL of oxygen per kilogram of body mass per minute.

The overall approach and the detailed procedure used to collect or select data to answer a research question, including the choice of methods, equipment, sampling and controls.

The shortest training cycle, usually about one week, that sets out the content, order and intensity of individual sessions and the recovery between them.

A nutrient needed in small amounts (milligrams or micrograms per day), such as a vitamin or mineral, that provides no energy itself but is needed to release energy and to build and maintain tissues.

A mental training practice of paying attention, on purpose and without judgement, to present-moment experience, repeatedly noticing when the mind wanders and returning attention to a chosen focus.

The volume of air breathed in or out per minute, equal to tidal volume multiplied by respiration rate and measured in L min⁻¹; about 6–8 L min⁻¹ at rest.

Structures inside cells, including muscle fibres, in which the Krebs cycle and electron transport chain use oxygen to resynthesise large amounts of ATP.

The process of imitating a behaviour that has been observed in another person, the model; in social learning theory it depends on attention, retention, motor reproduction and motivation.

Physical activity at an intensity of about 3 METs or more, the range in which most of the health benefits of activity are gained.

The turning effect of a force about a fulcrum, equal to the force multiplied by the perpendicular distance from the fulcrum to its line of action, measured in newton metres.

The resistance of a body to a change in its angular motion, depending on its mass and how far that mass is distributed from the axis of rotation; measured in kg m².

The quantity of motion possessed by a moving body, the product of its mass and velocity, $p = mv$; a vector measured in kg m s⁻¹.

A single sugar unit, such as glucose, fructose or galactose; the simplest carbohydrate and the building block of disaccharides and polysaccharides.

A system that tracks the three-dimensional position of the body over time, usually with several infrared cameras following reflective markers on anatomical landmarks, to calculate joint angles and velocities.

The internal and external forces that determine the direction of a person’s behaviour (what they choose to do) and the intensity of their effort (how hard and how long they try).

The psychological environment that a coach, teacher, parent or peer group creates through session design, instruction, feedback and rewards, which signals how success is defined and influences athletes’ motivation.

Imagery of the feelings of arousal, relaxation, stress and anxiety in competition, used to raise or lower arousal towards the optimal level.

Imagery of being mentally tough, confident, focused and in control in difficult situations, used to build confidence and self-efficacy.

Imagery used to increase motivation, set and pursue goals, control arousal and anxiety, or build confidence and mental toughness.

Self-talk that aims to increase effort, energy, confidence or positive mood, or to control arousal, such as "come on" or "stay strong".

Imagery of specific goals and goal-oriented behaviour, such as standing on the podium, winning a final or achieving a personal best.

The process by which movement skills are acquired, refined and retained through practice and experience, producing relatively permanent changes in the capability to perform them.

A neuron that carries impulses from the central nervous system to an effector, such as a skeletal muscle or gland.

A single motor neuron together with all the muscle fibres it innervates; the functional unit of muscle contraction, whose fibres all contract together.

The activation of additional motor units by the nervous system to increase the force of a muscle contraction.

The systematic observation, description and evaluation of a movement or skill, usually by dividing it into phases, to understand how it is performed and to identify improvements in performance, safety or health.

The time taken from the start of a movement to its completion, which together with reaction time makes up response time.

A 48-item self-report questionnaire, based on the 4Cs model, that measures overall mental toughness and its components of challenge, commitment, control and confidence; the MTQ10 is a 10-item version.

A theory proposing that cognitive anxiety has a negative linear relationship with performance, somatic anxiety an inverted U relationship, and self-confidence a positive linear relationship.

A maximal field test in which participants run 20 m shuttles at a pace set by beeps that gets faster every minute; the level reached is used to estimate VO₂ max.

A single skeletal muscle cell, long, cylindrical and multinucleated, containing many myofibrils and surrounded by the sarcolemma.