more glossary terms. gra to max

recognizing that a force is the tendency to change the motion of an object (change the direction or speed), ground reaction force is the tendency of contact with the ground to change the direction or speed of motion of an object that is in contact (surface beneath an object).  

the active increase of body or organ/tissue size, typically related to development, but also adaptation or hypertrophy.

a hormone released by the anterior pituitary, also known as somatotropin, with direct target receptors throughout the body including adipose cells, liver, skeletal muscle, and bone. Somatotropin also stimulates the release of “insulin-like growth factor” (IGF-1) which stimulates growth and regeneration. Wikipedia

of or relating to the blood; 

the production of blood cells from haematopoietic stem cells, mainly in bone marrow.  This includes red blood cells, white blood cells and platelets.  Haematopoiesis leading to erythrocyte synthesis is stimulated by erythropoietin.

describing stem cells that have the capacity to become blood cells.

a large haeme-containing protein in red blood cells that binds oxygen. Each molecule of Hb will bind 4 molecules of oxygen in a cooperative manner, meaning that the binding of one molecule of O₂ will enhance the subsequent binding of additional O₂. The binding capacity can be expressed as 1.34 ml of oxygen per gram of Hb. Hb can exist in the deoxygenated state as deoxyhaemoglobin and in the oxygenated state as oxyhaemoglobin. Wikipedia

oxyhaemoglobin and deoxyhaemoglobin

that proportion of the haemoglobin that has oxygen bound; opposite of deoxyhaemoglobin

two cells, or groups of cells that are reciprocally inhibited such that when one is active the other is inactive; important for reciprocal activation as in during locomotion.

the time needed for something to change by 50 % when the change is exponential.  

an exercise intensity between the aerobic threshold and the anaerobic threshold.   This is also referred to as vigorous exercise, or the exercise intensity that is prescribed for health benefits. 

a state of physical and emotional well-being, healthy. Wikipedia

the average rate at which the heart beats or the number of ejections of stroke volume per minute.  Typical values for heart rate at rest are 50 to 80 beats per min.    

exposure to a warm environment for 7 days or more results in changes in the way the body responds to heat exposure.  Heat acclimation (or acclimatization) results in initiating sweating at a lower body temperature, increased sweat output, and lower osmolality of sweat.  These adaptations permit the individual to maintain a lower body temperature on exposure to heat with or without exercise.

heat balance is when body temperature is maintained constant because the internal heat production and the loss of heat from conduction, convection, and evaporation are equal.

the amount of heat energy that can be absorbed per degree change in temperature. The heat capacity of water is greater than the heat capacity of air.  Wikipedia

belongs to a class of proteins that maintains the proper structure of other proteins. Heat-shock proteins bind to proteins that are under threat to denature or become nonfunctional; for this function they are referred to as “chaperone” proteins.  Additional isoforms of HSP exist.  The levels of HSPs increase during stressful conditions (e.g. exercise). 

Elevated body temperature with normal compensation (increased sweating, increased blood flow to the skin, increased ventilation). 

body temperature above 41°C accompanied by decreased sweating, hyperventilation, and rapid heart rate.  The key is that the body is no longer compensating for increased body temperature; dehydration could be severe. 

a heat illness resulting from a sustained high body temperature with diminished ability to compensate.  Risk for heat stroke include sustained exercise in a warm environment without adequate fluid replacement.  Symptoms include hot dry skin, high body temperature, dizziness, headache and loss of coordination.  Heat stroke can result in seizures, rhabdomyolysis and kidney failure.   Wikipedia

the idea that motor units are activated in a specific order from smallest to largest was first proposed by Robert Henneman. The idea arose from the evaluation of reflex activation of motor units; the smallest of which appear to be most sensitive. It is generally believed that as voluntary effort increases, additional force or power is obtained by recruitment of additional motor units and that newly recruited motor units are larger than already recruited units. Wikipedia

a hexagon is a six-sided shape.  A hexagonal array has 6 common elements around a central object.  In the case of skeletal muscle, there are 6 actin filaments around each myosin thick filament.  A cross-section of muscle, imaged by electron microscopy shows 6 dots (transected actin filaments) surrounding each myosin (also represented in the image as a dot, but larger than the dots representing actin). 

fluid accumulation in the brain, resulting in increased fluid pressure within the skull.  Symptoms include: headache, nausea and blurred vision.

fluid accumulation in the lungs resulting from high altitude exposure. Symptoms include chest congestion, a feeling of breathlessness (dyspnea) and inability to persist in exercise.   

a vague classification of exercise intensity, also referred to as hard; typically considered to be above the anaerobic threshold but below the maximal oxygen uptake.

a technique that allows identification of chemical composition of tissue at the microscopic level.  

a process, function, or outcome that depends on recent events associated with the parts involved. History dependence of muscle contraction refers to the fact that the contractile response observed for a given stimulation at a given length depends on the recent muscle activity. For example, fatigue and potentiation of contractile response are considered history dependent properties of muscle. Shortening induced depression and stretch induced enhancement of force are also history dependent properties. These latter properties of muscle allow less or more (respectively) force at a given length if shortening or lengthening occurred in the active condition prior to arriving at the measurement length.

keeping things constant. Homeostasis refers to keeping the internal environment constant with respect to temperature and ion concentration. Wikipedia

Homeostatic (adjective)

referring to a situation where chemical and thermal conditions are constant.

immunity provided by substances normally found in the extracellular body fluids.  This includes antibodies, complement proteins, cytokines and other substances that participate in the inflammatory response.

muscle fibre containing more than one myosin isoform. The presence of hybrid fibres prevents the categorization of some motor units as type I, type IIa and type IIx. Hybrid fibres typically contain two myosin isoforms (type I; IIa or type IIa; IIx).

adding water to the body is hydration.  This is typically through consumption of fluids composed mostly of water.  Adequate hydration will keep the body in water and electrolyte balance.

relating to water or fluid without consideration for flow. Hydrostatic pressure in the vascular system is measured as a lateral pressure in a blood vessel

hydrostatic weighing: 

also known as underwater weighing; the gravitational effect on the body while completely submerged.  This hydrostatic weight is dependent on the density of the body being greater than that of water.  The more dense the body is, the more it will weigh in the underwater environment.

hydrostatic pressure

The fluid pressure detected in a tissue or between cells; generally in a confined space. Hydrostatic pressure is affected by gravity; a column of water will have a greater hydrostatic pressure at the bottom than near the top.

increased blood flow, typically achieved through vasodilation, but can also be caused by increased blood pressure. Two primary forms of hyperaemia exist: active and reactive. Active hyperaemia is increased blood flow resulting from increased metabolic rate and reactive hyperaemia results from temporary occlusion of blood flow. Wikipedia

hypervolaemia (noun):

when blood volume is greater than the normal amount

high partial pressure of carbon dioxide in the blood.  Normal arterial PCO₂ is 40-60 mm Hg. Values of PCO² greater than 75 are considered hypercapnic.  Hypercapnia can result from inadequate ventilatory response during exercise or breathing a gas with high CO² content.  Wikipedia

the increase in minute ventilation resulting from increased partial pressure of CO₂ in the arterial blood.  The increased PCO₂ is detected primarily by the central chemoreceptors and results in increased tidal volume and breathing rate.

growth by increasing cell number in contrast with increasing cell size (hypertrophy).

increased depth and/or rate of breathing.     Wikipedia

more polarized than is typical; when a membrane is polarized, there is a voltage difference across the cell membrane. This voltage difference is measured relative to the outside, and resting membrane potential of nerve and muscle cells is about -80 mV.  When the voltage difference is greater than this 80 mV, the membrane is said to be hyperpolarized.  

hyperpolarization-activated cation channels (Ih)

ion channels that allow only cations to pass through (Na+, K+ and Ca2+) that are activated (opened) when the cell membrane is hyperpolarized

high blood pressure. Moderate hypertension is pressure greater than 130/90 mm Hg, severe hypertension is pressure above 140/95 mm Hg.  Wikipedia

increase in size of a tissue. For example, muscle hypertrophy is an increase in cross-sectional area of individual muscles and results from resistance training.  Tissue hypertrophy may result from increases in cell size or number of cells.  In muscle, hypertrophy results from increased cell size.  Wikipedia

low blood sodium. The normal concentration of sodium (Na⁺) in plasma is 140 mM. When plasma sodium falls below 135 mM, it is considered hyponatremia.  Hyponatremia results from overconsumption of water and or low sodium intake.  Movement of sodium into muscle cells as a result of action potentials on the surface membrane may contribute. Wikipedia

hypernatremia (noun):

too much sodium in the blood. Generally greater than 145 mM is considered high and this becomes critical around 160 mM. Thirst is a primary symptom, and this can be fixed by drinking water.

Wikipedia

hyperhydrated (noun) hyperhydrate (verb):

When the body contains more water than is needed; this state can lead to dilution of important entities like sodium resulting in hyponatremia

low blood pressure, due to inadequate hydration, compromised cardiac output, or widespread vasodilation.  Hypotension can result in syncope. A special case is orthostatic hypotension which results from changing from a horizontal or seated position to an upright position.    

a part of the brain found under the thalamus that is responsible for regulation of secretion of a number of hormones by the anterior pituitary. The hypothalamus is responsible for autonomic function and control of hunger, thirst, sleep and fatigue. Circadian rhythms are generated in the hypothalamus. Wikipedia

 a proposed mechanism or theory that can be tested by research. Typically, the hypothesis is proposed in such a way that a given outcome of the research can disprove the mechanism.

inadequate alveolar ventilation or not breathing enough.  Symptoms of hypoventilation include decreased PaO₂ and increased PaCO₂.

low content of O₂ in the arterial blood.  This can be due to low PaO₂ or low oxygen carrying capacity, as in anemia or carbon monoxide poisoning.    

when the partial pressure of O₂ in the arterial blood or a part of the body is less than adequate, then the condition is referred to as hypoxic.  Hypoxia can be due to assent to altitude, compromised ventilation or cardiac output or can be imposed by breathing an air mixture with low O₂ content.  Hypoxia results in a blue tinge to the skin due to the color of deoxygenated blood.

decreased partial pressure of O₂ in the alveolar spaces results in vasoconstriction of the pulmonary arterioles.  This has a valuable effect when the hypoxia is regional, diverting blood flow to better ventilated regions but it can result in pulmonary hypertension when the hypoxia is more generalized.

the increase in minute ventilation resulting from decreased partial pressure of O₂ in the arterial blood.  The cause of the decrease in PO₂ could be exposure to altitude,  or impaired pulmonary gas exchange.  The decreased PaO₂ is detected by the carotid chemoreceptors and results in increased alveolar ventilation by increases in tidal volume and breathing frequency.

the bodies defense system that identifies foreign compounds in the body and destroys and eliminates them.  The immune system is composed of cells and proteins including antibodies that recognize specific molecules.

the study of the immune response in the body.  The body has several defense systems to protect against invasion of foreign substances and microorganisms. These systems of defense include: barriers, mucus membranes, antibodies and lymphocytes that attack foreign bodies and microorganisms. British Society for Immunology

the process in the body of monitoring the need for an immune response; detecting and ridding the body of infection and foreign bodies.

the impact factor is a measure of the number of citations for a given journal. The impact factor is calculated by considering the number of citations of articles published by a journal in a two-year period, divided by the number of articles published by that journal. The impact factor is generally considered a measure of the quality of a journal, but citations depend on a number of factors including but not limited to: the number of publications in a given field of study, availability of a journal (library subscriptions, open access, limited circulation), and notoriety of the author (this could be good or bad). The actual value of the impact factor depends on which sources are considered when quantifying the citations. For this reason, some impact factors can vary for a given journal. Wikipedia

when tissue is studied in its natural habitat, and only partly disturbed from in vivo circumstances, it is called “in situ”.  For example, a muscle is studied in situ when the tendon of an anaesthetized animal is disarticulated and connected directly to a force transducer while keeping the circulation intact.  Sometimes the neural connections are preserved and sometimes the nerve is severed and the peripheral stump can be stimulated to activate the muscle. Temperature is usually kept near physiological for the animal under study.

when tissue is studied after removal from the body or natural environment, this classification is “in vitro”.  Literally, this means “in glass”, but the term is often used more generally.  For example a muscle can be removed from an animal and studied in a tissue bath that allows direct measurement of force and length.  Typically, the tissue is placed in a solution that mimics extracellular fluid.

experimental procedures conducted while maintaining the intact living state.  In vivo research involves measurements while manipulating circumstances but keeping the body intact. In vivo research has the advantage that conditions that support and maintain life are preserved.  In vivo research keeps a realistic environment for the cells under study. This is in contrast with in vitro research which is conducted by removing tissue from the body and studying it in an artificial environment.

a second gate on an ion channel. For example, the fast sodium channel of axon and muscle fibre membranes has a molecular structure in the pore of the channel that closes when the membrane potential becomes positive during the action potential. This inactivation gate reopen only after the activation gate has closed. The absolute refractory period lasts until the inactivation gate opens.

when a random sample is chosen from a defined population and a specific measure is taken to estimate a property of the population, it is called inferential statistics.

the response of the body or a body-part to injury infection that includes: increased blood flow, swelling and tenderness or pain.  

natural processes in the body that detect the presence of bacteria, viruses and other foreign substances without specific identification of the threat.

the number of muscle fibres innervated by a single motor neuron.  Also, the number of muscle fibres in a motor unit.  All muscle fibres innervated by a given motor neuron will be of the same muscle fibre-type.

magnitude of impediment to current flow, usually across a membrane. Current flows in the form of ions and will occur by the path of lowest resistance.Membrane resistance is affected by surface area and open ion channels.

narrow tendinous band of stiff connective tissue, separating two parts of an otherwise continuous muscle.  

the act of breathing in.  Air moving into the lungs.

the extra air that can be inhaled during maximal effort from the end of a normal inspiration.

a hormone released by pancreatic beta cells in response to high blood sugar.  Insulin assists the transport of glucose into cells of the body by mobilizing GLUT 4 transporters from intracellular vesicles to the external membrane.  These transporters bring glucose from the extracellular space into the cell. 

insulin-like growth factor-1 (IGF-1)

is a hormone that promotes tissue growth. It has a structure similar to insulin and is produced by many tissues, including the skeletal muscle. Wikipedia

amplitude or size of the electromyographic (EMG) signal after rectifying or making all values positive.  EMG is a measurement of the electrical signals on the skin (or within the muscles) generated in the muscles by conduction of the action potentials along the muscle fibre membranes.  These signals typically oscillate around a zero voltage, so averaging the signal will give a value of zero.  However, calculating the absolute value or taking the square of all values will give positive values.  Integrated EMG is the sum of this positive activity over time.  

an indication of the energy cost of exercise, relative to maximal oxygen uptake. Also, an indication of how difficult it is to sustain the exercise. Classifications of intensity are: easy, mild, moderate, vigorous and hard, or mild, moderate heavy and severe.  Intensity can be quantified by physiological response (heart rate, relative oxygen uptake, METs) or by perceived exertion (Borg scale).  

the higher the intensity of exercise, the shorter the duration of exercise.  Performing a series of time-trials at constant intensity (speed of running or power output on a cycle ergometer) to the limit of endurance allows plotting of this relationship.  When the duration of trials is kept between 2 and 20 min, the critical speed or critical power concept can be investigated.

the environment inside the body, but outside the individual cells that make up the body.  The internal milieu refers to the extracellular space. This is the environment in which the cells of the body exist and that must be maintained in a relatively constant state for viability of the individual cells of the body. Wikipedia

neither sensory nor motor but a connecting neuron, forming a neural circuit in the central nervous system. Wikipedia

when a single stimulus is applied to the motor nerve or directly to the muscle during a voluntary contraction, the resulting contractile response is called an interpolated twitch.  The interpolated twitch will have no amplitude if the person is able to maximally activate all motor units of the muscle in question.

the duration of time between action potentials on a nerve or muscle fibre. The inverse of the interspike interval is the frequency of activation.

relating to the space between cells within a tissue.  This can refer to the fluid, connective tissue or specific molecules.

the space between cells, also called interstitial space.  This space is filled with fluid called interstitial fluid or intercellular fluid.

between myofibrils. The space between myofibrils is called the intermyofibrillar space. The intermyofibrillar space is occupied by sarcoplasm, mitochondria, sarcoplasmic reticulum, and glycogen.

exercise for the purpose of improving physical performance that involves repeated trials at high intensity with rest intervals between trials.  The rest allows sufficient recovery that a high intensity or effort can be achieved.

within the confines of the cellular membrane. Everything inside the membrane would be considered intracellular and everything outside the membrane would be considered extracellular. Wikipedia

characteristic features of an object or system. Intrinsic properties can refer to a molecule, a cell or an organ and refer to aspects like mass, structure and changes that occur within the object or system.

a charged particle (element of molecule).  An ion can be positive or negative, based on the presence of one electron more or less than the number of protons in the atom or molecule. A cation is a positive ion and an anion is a negative ion. Examples of ions in the body are Na⁺, Cl^-, K⁺, H⁺ and lactate (La^-).

ion channel

protein structure embedded in the plasmalemma that allows regulated transfer of ions.  Most ion channels are selective for one ion or similar ions.  An example of an ion channel is the sodium channel that is activated to allow an action potential to be propagated along a muscle fibre or nerve axon.

ion pump

protein structure that transfers specific ions across a plasmalemma, usually against its concentration gradient, therefore requiring energy.  An example of an ion pump is the Ca²⁺ ATPase; which is present in the sarcolemma and the membrane of the sarcoplasmic reticulum.  

a ligand-gated receptor that has a direct effect on transmembrane permeability to a specific ion.

ionotropic nicotinic acetylcholine receptors

a receptor that binds acetylcholine, but could also bind nicotine, that results in a direct change in permeability of the membrane to a specific ion or class of ions. Acetylcholine receptors can be muscarinic or nicotinic depending on their susceptibility to bind these two potential ligands. 

referring to the same side of the body as some reference point. Opposite of contralateral (opposite side).

a lack of blood flow. blood flow is prevented from reaching a given tissue then that tissue is ischaemic. 

ischaemic (adjective):

describing a tissue that is deprived of blood flow

a protein that is a member of a group of proteins with the same function that originate from the same gene. Genetic differences, via splicing or duplication, of a single gene result in a variety of proteins with the same structural background. Each isoform may have unique functional properties.

motion at a constant velocity or angular velocity. Dynamometers are often created to regulate the rate of angle change of an isolated joint. Isokinetic knee extension is probably the most studied isolated motion of the human body.

when contraction of a muscle results in no length change, it is referred to as static or isometric. In reality, a truly isometric contraction is difficult; a fixed-end contraction has no change in length of the muscle-tendon unit, but the tendon elongates in proportion to the force of contraction and the muscle fibres shorten as the tendon elongates. This should be referred to as auxotonic, not isometric.

a line on a map or a graph linking equal values.  A common example of an isopleth is a contour line on a map, connecting areas of equal elevation; something that would otherwise not be perceived from looking at a flat map.

this term actually means “constant force” and represents a valuable way to study muscle contractions.  To keep force constant through a range of motion is not an easy task because the effective force of gravity acting on a mass changes as the angle of the joint changes.  Also, the moment arm distance may change as joint angle changes.  To keep force constant during a muscle contraction, physiologists usually study the muscle directly connected to a force/length transducer system with feedback control to keep the load constant.

when a moment is produced at a joint, the opposing bones must press on each other with a force (equal and opposing) that is dependent on the moment. This force between opposing bones is called the joint reaction force.

transmembrane protein that contains a pore through which potassium can selectively move. 

Kainic acid dissociates to Kainate and H+. Kainate binds to one of four types of central nervous system receptors that are sensitive to glutamate and is excitatory. Glutamate receptors are considered to be ionotropic receptors.

a unit of measure for energy. It is equivalent to the amount of heat required to increase the temperature of 1kg of water by 1°C.  A kilocalorie is sometimes depicted as Calorie where the capital C signifies kilocalorie rather than calorie.

the scientific study of human and animal movement.  Kinesiology is a multidisciplinary field of study that incorporates chemistry, physics and biology as well as sociology, psychology and anatomy. Understanding movement can include acute studies to understand the function of the various body parts and their role in movement and can also include the study of the health benefits of regular physical activity

the rate at which a reaction or process occurs. The kinetics of oxygen uptake refers to how the rate of oxygen uptake changes at the onset of exercise or the transition from one intensity to another.  

a three-carbon molecule, derived from glucose by glycolysis. Also, the dissociated product (base) of lactic acid (C₃H₆O₃), which is a weak acid and exists in vivo primarily in the dissociated form. Wikipedia

lactate threshold

when the blood lactate concentration changes substantially, during an incremental exercise test, the intensity prior to that increase is called the lactate threshold.  There are many criteria for choosing the substantial change, so the actual intensity of exercise identified as the lactate threshold can vary considerably, but usually is between the aerobic threshold and the anaerobic threshold.

lactic acid is a 3-carbon molecule (C₃H₆O₃) dissolved in body fluids.  It dissociates easily to lactate and H⁺.  Lactate is a product of glycolysis, so it is produced quickly during exercise of sufficient intensity to activate this enzymatic process.   Contrary to popular belief, lactic acid does not cause muscle pain and is not likely a direct cause of fatigue.

protein connections from the Z-disks to the extracellular matrix (costameres) allow force to be transmitted to adjacent connective tissue and myocytes.  These costameres serve to keep the sarcomeres aligned across the whole muscle, from cell to cell.  Lateral transfer of force allows inactive myocytes to be shortened during submaximal dynamic contractions and permits force generated in one muscle fibre to be transferred along the connective tissue associated with several fibres.

physical activity performed outside of the occupational or domestic setting.

based on the observation that optimal length (length at which the highest force occurs) is longer for submaximal activation than for maximal activation, the muscle is thought to have an altered activation at longer lengths.  The actual mechanism appears to be related to increased calcium sensitivity due to closer proximity of the myosin heads with the actin filaments.

an ion channel, that has a binding location for a molecule which, when bound to the binding site will cause opening or closing of the pore of the membrane ion channel. The acetylcholine receptor of the end-plate region of the myocyte is an example of a ligand-gated ion channel. ligand-gated ion channels are also known as ionotropic receptors.

fitting the data to a linear equation.  The least squares method is used to find the best fit of a slope and intercept to a set of data.  The least squares method finds the smallest variation of the square of the difference between data values and the value predicted by an equation.

an antigenic lipid molecule joined with several sugar moieties, typically found in the membrane of gram negative bacteria. Also called an endotoxin.

the act of moving the entire body over some distance; for example, walking from your house to the University.  The human body is typically capable of several forms of self-propelled locomotion including running, walking, skating, skiing, swimming, cycling, skate-boarding etc. 

having the ability to move or contributing to movement. 

locomotor muscles

skeletal muscles that contribute to locomotion, the movement of the body that accomplishes relocation.

research conducted to quantify change across some interval of time is considered longitudinal.  Typically, in exercise physiology, this type of research would involve a quantification of changes due to an intervention that would be expected to have some outcome with respect to physical capability.  Longitudinal studies are complicated when growth and development also contribute to the change that would be expected from the intervention.

making a system less responsive to excitatory stimuli for a prolonged time (hours).  In the LTD state, synaptic input is less effective at activating a neural connection.  long-term depression (LTD)

long-term potentiation (LTP)

an enhanced responsiveness to synaptic input that lasts for hours.

also known as “mild” intensity.  There are often considered to be two “zones” of light intensity exercise: just slightly above rest and substantially above rest but below moderate exercise.  Moderate exercise is the equivalent of a brisk walk for a healthy person. 

a distributed series of tissues and vessels including a thin walled vascular system that parallels the venous system, returning fluid (lymph) lost from the capillaries when blood passes through tissue.  The lymphatic system includes lymph nodes, the thymus, spleen and tonsils and it plays an important role in the immune response in the body. Lymph vessels have valves, like the veins to permit only anterograde flow.  The movement of fluid through the lymphatic vessels is accomplished by intermittent compression of the vessels as would occur during intermittent muscle contractions.  The lymphatic vessels join the venous vascular system  at the subclavian veins.

a small white blood cell with a small round nucleus, found in high concentration in lymph.  There are three types of lymphocyte: T cell, B cell and natural killer cell.

an enzyme that is part of the innate immune system that can hydrolyze specific molecules that are part of gram positive bacterial cell walls.  Lysozymes are present in human milk as well as other secretions: tears, saliva and mucus.

Microscopic line along the middle of the sarcomere, dividing the A-band into two parts.  The M-line is composed of several proteins including myomesin and creatine kinase that link the thick filaments in an expandable matrix that allows thickening and narrowing of the myofibril as the muscle is shortened or elongated respectively.

a nutrient that is required in relatively large amounts in the diet. The three energy providing macronutrients are carbohydrate, protein, and fat. Wikipedia

this approach to statistical evaluation is based on whether or not a change or difference is meaningful.  This could be related to whether or not a treatment is clinically relevant or an improvement in performance is sufficient to make a difference.

a cytokine that regulates protein synthesis. mTOR is a kinase which phosphorylates and activates proteins (e.g. S6Kinase and 4E-BP1), which are involved in the cellular process of translation.

growth and development from the immature state towards the fully mature condition.

the oxygen deficit represents the quantity of oxygen uptake that would be expected during exercise of a given type and intensity but was not evident due to an equivalent amount of anaerobic energy provided for the exercise.  The rise in oxygen uptake at the beginning of exercise does not provide all of the energy for the exercise, so the difference between energy required and energy provided by oxygen uptake is called the oxygen deficit; this deficit is expressed as an oxygen uptake equivalent.  When the magnitude of this deficit is as large as possible, then it is called the maximal accumulated oxygen deficit.  Theoretically, this MAOD should be represented by the energy equivalent of the anaerobic work capacity, but this may not be the case.

the intensity of exercise that elicits maximal oxygen uptake.  This intensity is often defined according to the exercise intensity during an incremental test that first elicits maximal oxygen uptake, however, when duration of exercise is longer, a lower intensity of exercise is likely to elicit maximal oxygen uptake.

the highest intensity of exercise that allows a steady state for blood lactate.  More specifically, MLSS is often defined as the highest intensity of exercise for which blood lactate does not increase more than 1 mM (some investigators have used 0.5 mM) during the time from 10 min to 30 min of constant intensity exercise.