adenosine triphosphate (ATP) is a high energy compound that stores and transfers energy to body cells, allowing them to perform their specialised functions, such as muscle contraction.
aerobic interval training involves alternating sessions of work and recovery. The rest period is important in differentiating aerobic interval training from anaerobic interval training.
aerobic metabolism is the breakdown of fuel in the presence of oxygen to produce energy (ATP).
aerobic threshold refers to a level of exercise intensity that is sufficient to cause a training effect. This is approximately 70 per cent of a person’s maximal heart rate (MHR).
aerobic training zone refers to a level of intensity that causes the heart rate to be high enough to cause significant training gains.
anaerobic means that the reaction occurs in the absence of oxygen.
anaerobic glycolysis is a process where glucose is broken down in the absence of oxygen to produce energy.
anaerobic threshold refers to a level of intensity in physical activity where the accumulation of lactic acid in the blood increases very quickly.
atrophy refers to wasting away or decrease in size.
capillaries are tiny blood vessels that connect the smallest arteries to the smallest veins.
cardiac output is the amount of blood pumped by the heart per minute.
chemical energy is energy stored in bonds between atoms.
circuit training requires participants to move from one ‘station’ to another, performing specified exercises at each until they complete the circuit.
creatinephosphate (CP) is an energy-rich compound that serves as an alternative energy source for muscular contraction.
dynamic stretching uses speed and momentum with movements experienced in a game to increase flexibility.
Fartlek (‘speed play’) training participants vary their speed and the terrain on which they are working, ultimately engaging both anaerobic and aerobic energy systems.
fast-twitch musclefibres (or type II fibres) reach peak tension quickly and are recruited for power and explosive movements such as throwing and lifting.
flexibility is the range through which joints and body parts are able to move.
glycogen is the storage form of glucose and is used for fuel when blood glucose levels decline.
glycolysis is the process of using glycogen or glucose as fuel.
haemoglobin is the substance in blood that binds to oxygen and transports it around the body.
high intensity interval training (HIIT) involves repeated bouts of high intensity exercise followed by varying periods of complete rest of recovery at lower intensity.
hypertrophy is the enlargement of muscle fibres in response to exercise.
kilojoules (or calories) measure the energy value of food. A calorie is the equivalent of 4.2 kilojoules.
lactate inflection point (LIP) is a point beyond which a given power output cannot be maintained. It is characterised by lactic acid accumulation and decreased time to fatigue.
lactate threshold is the point at which lactic acid accumulates rapidly in the blood.
193lactic acid is a by-product of the incomplete breakdown of carbohydrate in the absence of oxygen.
lung capacity is the amount of air that the lungs can hold.
mechanical energy is motion or movement energy.
metabolism is the sum of all chemical processes within cells that transforms substances into energy.
mole is the gram-molecular weight of a substance. 1 mole (mol) = 1000 millimoles (mmol).
muscle hypertrophy is a term that refers to muscle growth together with an increase in the size of muscle cells.
oxygen uptake is the ability of the working muscles to use the oxygen being delivered.
plyometrics refers to a special range of exercises in which a muscle is lengthened using an eccentric contraction. This is rapidly followed by a shortening or concentric contraction.
PNF stretching is a progressive cycle incorporating a static stretch, an isometric contraction and a period of relaxation in the lengthened position. It is aimed at stretching and strengthening muscle in a safe movement.
respiration is the process of breathing.
resting heart rate is the number of heartbeats per minute while the body is at rest.
resynthesis is the process of restoring ATP to its former state.
slow-twitch musclefibres (or type I fibres) contract slowly and for long periods of time. They are recruited for endurance-type activity such as marathons.
static stretching is a safe form of stretching in which the stretch is held for a period of 10–30 seconds.
strength is the ability of a muscle or muscle group to exert a force against a resistance.
stretch reflex is an involuntary muscle contraction that prevents fibre damage if muscles are lengthened beyond their normal range.
194stroke volume is the amount of blood ejected by the left ventricle of the heart during a contraction. It is measured in mL/beat.