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To be at your peak there needs to be an overall understanding on how the body moves. Knowing how and why the body moves allows us to focus on the needs of the athlete and ways to improve the overall functioning of the athletes. We take pride in providing the appropriate scientific material that will help increase a better understanding on how the body is structured and how and why the body moves the way it does. Don't miss out on your potential by not finding out what your body is efficient at or deficient at.

A

    Absolute VO2

    The amount of Oxygen consumed over a given period .

    Acidosis

    An abnormal increase in blood hydrogen ion concentration

    Acids

    Compounds capable of giving up hydrogen ions into solution.

    Acromegaly

    A condition caused by hypersecretion of growth hormone from the pituitary gland; characterized by enlargement of the of the extremities, such as jaw, nose and fingers.

    Actin

    A structural protein of muscle that works with myosin in permitting muscular contraction

    Action Potential

    The all or none electrical event in the neuron or muscle cell in the polarity of the cell membrane is rapidly reversed and then reestablished.

    Adenosine Diphosphate (ADP)

    A molecule that combines with inorganic phosphate to form ATP.

    Adenosine Triphosphate (ATP)

    The high energy phosphate compound synthesized and used by cells to release energy for cellular work.

    Adenylate Cyclase

    Enzyme found in cell membranes that catalyzes the conversion of ATP to cyclic AMP.

    Adequate Intake (AI)

    Recommendations for nutrient intake when insufficient information is available to set an RDA standard.

    Adrenal Cortex

    The outer portion of the adrenal gland. Synthesizes and secretes corticosteroid hormones, such as cortisol, aldosterone, and androgens 

    Adrenaline

    see epinephrine

    Adrenocortcotrophic Hormone (ACTH)

    A hormone secreted by the anterior pituitary gland that stimulates the adrenal cortex.

    Aerobic

    In the presence of oxygen.

    Afferent Fibers

    Nerve fibers (sensory fibers) that carry neural information back to the central nervous system.

    Afferent Neuron

    Sensory neuron carrying information toward the central nervous system.

    Aldosterone

    A corticosteroid hormone involved in the regulation of electrolyte balance.

    Alkalosis

    An abnormal increase in blood concentration of OH- ions, resulting in a rise in arterial pH above 7.45.

    Alpha Receptors

    A subtype of adrenergic receptors located on cell membranes of selected tissues.

    Alveolar Ventilation

    The volume of air that ventilates all the perfused alveoli,equal tototal ventilation minus dead space ventilation.The normal average is between and L/min.

    Alveoli

    A microscopic air sacs located in the lung where gas is exchange occurs between respiratory gases and the blood.

    Amenorrhea

    The absence of menses.

    Anabolic steroids

    A percription drug that has anabolic, or growth stimulating, characteristics similar to that of the male androgen, testosterone.

    Anaerobic

    Without oxygen.

    Anaerobic Threshold

    A commonly used term meant to describe the level of oxygen consumption at which there is a rapid and systematic increase in blood lactate concentration. Also known as lactate threshold

    Anatomical Dead Space

    The total volume of the lung that does not participate in gas exchange.

    Androgenic steroid

    A compound that has the qualities of an androgen; associated with masculine characteristics.

    Androgens

    Male sex hormones. Synthesized in the testes and in limited amounts in the adrenal cortex. Steroids that have masculinizing effects

    Angina Pectoris

    Chest pain due to a lack of blood flow (ischemia) to the myocardium.

    Angiotensin I and II

    These compounds are polypeptides formed from the cleavage of a protein (angiotensinogen) by the action of the enzyme renin produced by the kidneys, and converting enzyme in the lung, respectively

    Anorexia Nervosa

    An eating disorder characterized by rapid weight loss due to failure to consume adequate amounts of nutrients.

    Anterior Hypothalamus

    The anterior portion of the hypothalamus. The hypothalamus is an area of the brain below the thalmus that regulates the autonomic nervous system and the pituitary gland.

    Anterior Pituitary

    The anterior portion of the pituitary gland that secretes follicle - stimulating hormone, luteinizing hormone, adrenocorticotrophic hormone, thyroid- stimulating hormone, and prolactin.

    Antidiuretic hormone (ADH)

    Hormone secreted by the posterior pituitary gland that promotes water retention by the kidney.

    Aortic Bodies

    Receptors located in the arch of the aorta that are capable of detecting changes in arterial PO2

    Apophyses

    Sites of muscle tendon insertion in bones.

    Arrhythmia

    Abnormal electrical activity activity in the heart.

    Arteries

    Large vessels that carry arterialized blood away from the heart .

    Arterioles

    A small branch of an artery that communicates with a capillary network.

    Articular Cartilage

    Cartilage that covers the ends of bones in a synovial joint.

    Atherosclerosis

    A pathological condition in which fatty substances collect inside the lumen of arteries.

    ATPase
    Enzyme capable of breaking down ATP to ADP + Pi + energy.
    ATP-PC system

    Term used to describe the metabolic pathway involving muscle stores of ATP and the use of phosphocreatine to rephosphorylate ADP. This pathway is used at the onset of exercise and during short-term, high-intensity work.

    Artioventricular Node (AV node)

    A specialized mass of muscular tissue located in the interventricular septum of the heart; functions in the transmission of cardiac impulses from the atria to the ventricles.

    Autologous Transfusion

    Blood transfusion where the individual receives his or her own blood.

    Autonomic Nervous System

    Portion of the nervous system that controls the actions of visceral organs.

    Autoregulation

    Mechanism by which an organ regulates blood flow to match the metabolic rate.

    Axon

    A nerve fiber that conducts a nerve impulse away from the neuron cell body

B

    Basel metabolic rate (BMR)

    Metabolic rate measured in supine position following a 12 hour fast , and 8 hours of sleep.

    Bases

    Compounds that ionize in water to release hydroxyl ions (OH-) or other ions that are capable  of combining with hydrogen ions.

    Beta Oxidation

    Breakdown of free fatty acids to form acetyl- COA

    Beta Receptor Agonist

    A molecule that is capable of binding to some degree, with norepinephrine.

    Beta Receptors

    Adrenergic receptors located on cell membranes. Combine mainly 

    Bioenergetics

    The Chemical processes involved with the production of cellular ATP.

    Biological Control Systems

    A control system capable of maintaining homeostasis within a cell or organ system in a living creature.

    Blood Boosting

    A term that applies to the increase of the blood's hemoglobin concentration by the infusion of additional red blood cells. Medically termed induced erythrocythemia.

    Blood Doping

    see Blood Boosting.

    Blood Packing

    see Blood Boosting.

    Bohr Effect

    The right shift of the oxyhemoglobin dissociation curve due to a decrease of blood pH. Results in a decreased affinity for oxygen.

    Bradycardia

    A resting heart rate less than sixty beats per minute.

    Brain Stem

    Portion of the brain that includes midbrain, pons, and medulla.

    Buffer

    A compound that resists pH change.

    Bulimia

    An eating disorder characterized by eating and forced regurgitation.

    Bulk Flow

    The mass movement of molecules from an area of high pressure to an area of lower pressure.

C

    Calcitonin

    Hormone, released from the thyroid gland, that plays a minor role in calcium metabolism.

    Calmodulin

    part of second messenger system involving calcium that results in changes in the activity of intracellular enzymes.

    Capillaries

    Microscopic blood vessels that connect arterioles and venules. Portion of vascular system where blood/tissue gas exchange occurs.

    Cardiac accelerator nerves

    Part of the sympathetic nervous system that stimulates the SA node to increase heart rate.

    Cardiac Output

    The amount of blood pumped by the heart per unit of time; equal to product of heart rate and stroke volume.

    Cardiovascular control center

    The area of the medulla  that regulates the cardiovascular system.

    Carotid Bodies

    Chemoreceptors located in the internal carotid artery; respond to changes in arterial PO2, PCO2, AND pH.

    Catecholamines

    Organic compounds, including epinephrine, noreepinephrine, and dopamine.

    Cell Body

    The soma, or major portion of the body of a nerve cell. Cointains the nucleus.

    Cell Membrane

    The lipid-bilayer envelope that encloses the cells. Called the sarcolemma in the muscle cells.

    Cellular Respiration

    Process of oxygen consumption and carbon dioxide production in cells; example bioenergetics

    Central Command

    The control of the cardivascular or pulmonary system by cortical impulses.

    Central Nervous System (CNS)

    Portion of the nervous system that consists of the brain and spinal cord.

    Cerebellum

    Portion of the brain that is concerned with fine cordination of skeletal muscles during movement.

    Cerebrum

    Superior aspect of the brain that occupies the upper cranial cavity. Contains the motor cortex.

    Chemiosmotic hypothesis

    The mechanism to explain the aerobic formation of ATP in mitochandria.

    Cholesterol

    A twenty-seven-carbon lipid that can be synthesized in cells or consumed in the diet. Cholesterol serves as a precusor of steriod hormones, and plays a role in the development of atherosclerosis.

    Clo

    Unit that describes the insulation quality of clothing.

    Concentric action

    Occurs whan a muscle is activated and shortens.

    Conduction

    Transfer of heat from warmer to cooler objects that are in contact with each other. This term may also be used in association with the conveyance of neural impulses.

    Conduction disturbances

    Refers to a slowing or blockage of the wave of depolarization in the heart;

    Conductivity

    Capacity for conduction.

    Cori Cycle

    The cycle of lactate to glucose between the muscle and liver.

    Coronary artery bypass graft surgery (CABGS)

    The replacement of a blocked coronary artery with another vessel to permit blood flow to the mycardium.

    Cortisol

    A glucocorticoid secreated by the adrenal cortex upon stimulation by ACTH.

    Coupled reactions

    The linking of energy-liberating chemical reactions to "drive"  energy requiring reactions.

    Critical power

    A specific submaximal power output that can be maintained without fatigue.

    Cromolyn sodium

    A drug used to stabilize the membranes of mast cells and prevent an asthma attack.

    Cycle ergometer

    A stationary exercise cycle that allows accurate measurment of work output.

    Cyclic AMP

    A substance produced from ATP through the action of adenylate cyclase that alters several chemical processes in the cell.

    Cytoplasm

    The contents of the cell surronding the nucleus, called sarcoplasm in muscle cells.

D

    Daily Value

    A standard used in Nutritional labeling.

    Deficiency

    A shortcoming of some essential nutrient.

    Degenerative Diseases

    Diseases not due to infection that result in  a progressive decline in some bodily function.

    Delayed-onset muscle soreness (DOMS)

    Muscle soreness that occurs twelve to twenty-four hours after an exercise bout.

    Dendrites

    Portion of the nerve fiber that transmitts action potentials toward a nerve cell body.

    Dental Caries

    Tooth decay; related to sugar content in foods.

    Deoxyhemoglobin

    Hemoglobin not in combination with oxygen.

    Diabetes mellitus

    A condition characterized by high blood glucose levels due to inadequate insulin. Type I diabetics are insulin dependent, whereas Type II diabetics are resistant to insulin.

    Diabetic coma

    Unconscious state induced by a lack of insulin.

    Diacylglycerol

    A molecule derived from a membrane-bound phospholipid, phosphatidylinositol, that activates protein kinase C, and alters cellullar activity.

    Diaphragm

    The major respitory musclar responsible for inspiration. Dome Shaped-seperates the thoracic cavity from the abdominal cavity.

    Diastole

    Period of filling of the heart between contractions example: the resting phase of the heart 

    Diastolic blood pressure

    Arterial blood pressure during diastrole.

    Dietary Guidelines for Americans

    General statements related to food selection that are consitent with acheving and mintaining good health.

    Dietary reference intakes

    The framework for nutruient recommendations being made as a part of the revision of the 1989 RDA.

    Diffusion

    Random movement of molecules from an area of high concentration to low concentration.

    Direct calorimetry

    Assessment of the body's metabolic rate by direct measurement of the amount of heat produced.

    Dose

    The amount of drug or exercise perscribed to have a certain effect (or response)

    Double-blind research design

    An experimental design in which the subjects and the principal investigation are not aware of the expirmental treatment order.

    Double product

    The product of heart rate and systolic blood pressure; estimate of work of the heart.

    Dynamic

    Refers to an isotonic muscle action.

    Dynamic Stretching

    Stretching that involves controlled movement.

    Dynamometer

    Device used to measure force production. example: muscular strength

    Dyspnea

    Shortness of breath or labored breathing. May be due to various types of lung or heart diseases.

E

    Eccentric Action

    Occurs when a muscle is activated and force is produced but the muscle lengthens.

    Ectomorphy

    Category of somatotype that is rated for linearity of body form.

    Effect

    Change in variable due to a dose of exercise.

    Effector

    Organ or body part that responds to stimulation by an efferent neuron.

    Efferent fibers

    Nerve fibers that carry neural information from the central nervous system to the periphery.

    Efferent neuron

    Conducts impulses from the CNS to the effector organ.

    Ejection fraction

    The proportion of end-diastolic volume that is ejected during  a ventricular contraction.

    Electrocardiogram (ECG)

    A recording of the electrical changes that occur in the myocardium during the cardiac cycle.

    Electron transport chain

    A series of cytochromes in the mitochondria that are responsible for oxidative phosphorylation.

    Element

    A single chemical substance composed of only one type of atom.

    Endergonic reactions

    Energy requiring reactions

    Endocrine gland

    A gland that produces and secretes its products directly into the blood or interstitial fluid (ductless gland).

    Endomorphy

    The somatotype category that is rated for roundness (fatness)

    Endomysium

    The inner layer connective tissue surrounding a muscular fiber.

    Endorphin

    A neuropeptide produced by the pituitary gland having pain suppressing activity.

    End-plate potential (EPP)

    Depolarization of a membrane region by sodium influx.

    Energy of activation

    Energy required to intitiate a chemical reaction.

    Energy wasteful systems

    Metabolic pathways in which the energy generated in one reaction is used up in another that leads back to the first, creating a futile cycle and requiring a higher resting metabolic rate.

    Enzymes

    Proteins that lower the energy of activation and, therefore, catalyze chemical reactions, Enzymes regulate the rate of most metabolic pathways.

    Epidemiologic triad

    A model that shows connections between the environment, agent, and host that cause disease.

    Epidemiology

    The study of distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

    Epilepsy

    A neurological disorder manifested by muscular seizures.

    Epimysium

    The outer layer of connective tissue surrounding muscle.

    Epinephrine

    A hormone synthesized by the adrenal medulla; also called adrenaline.

    Epiphyseal plate (growth plate)

    Cartilaginous layer between the head and shaft of a long bone where growth takes place.

    EPOC

    An acronym for exercise post-exercise oxygen consumption.

    EPSP

    Excitary post-synaptic potential. A graded depolarization of a post-synaptic membrane by a neurotransmitter.

    Ergogenic aid

    A substance appliance, or procedure that improves performance.

    Ergometer

    Instrument for measuring work.

    Ergometry

    Measurement of work output.

    Erythrorocythemia

    An increase in the number of erythrocytes in the blood.

    Erythropoietin

    Hormone that stimulates red blood cell production.

    Estrogens

    Female sex hormones, including estradiol and estrone. Produced primarily in the ovary and also produced in the adrenal cortex.

    Evaporation

    The change of water from a liquid form to a vapor form.Results in the removal of heat.

    Exercise

    A subclass of physical activity.

    Exergonic reactions

    Chemical reactions that release energy.

    Extensors

    Muscles that extend a limb that is, increase the angle at a joint.

F

    FAD

    Flavin adenine dinucleotide serves as an electron carrier in bioenergetics.

    Fasciculli

    A small bundle of muscle fibers.

    Fast twitch fibers

    One of several types of muscle fibers found in skeletal muscle; also called Type II fibers; charcterized as having low oxidative capacity but high glycolytic capacity.

    Ferritin

    The iron-carrying molecule used as an index of whole-body iron status.

    Field Test

    A test of physical performance performed in the field (outside of laboratory).

    Flexors

    Muscle groups that cause flexion of limbs-that is, decrease the angle at a joint.

    Follicle-stimulating hormone (FSH)

    A hormone secreted by the anterior pituitary gland that stimulates the development of an ovarian follicle in the female and the production of sperm in the male.

    Food records

    The practice of keeping dietary food records for determining nutrient intake.

    Free fatty acid (FFA)

    A type of fat that combines with glycerol to form tricglycerides. Is used as an energy source.

G

    G Protein

    The link between the hormone-receptor interaction on the surface of the membrane and the subsequent events inside the cell.

    Gain

    Refers to the amount of correction that a control system is capable of achieving.

    General Adaptation Syndrome (GAS)

    A term defined by Selye in 1936 that describes the organism's response to chronic stress. In response to stress the organism  has a three stage response: (1) Alarm reaction; (2) stage resistance; (3) readjustment to the stress, or exhaustion.

    Glucagon

    A hormone produced by the pancreas that increases blood glucose and free fatty  acid levels.

    Glucose

    A simple sugar that is transported via the blood and metabolized by tissues

    Glucose polymer

    A complex sugar molecule that contains multiple simple sugar molecules linked together.

    Glycogen

    A glucose polymer synthesized in cells as a means of storing carbohydrate.

    Glycolysis

    A metabolic pathway in the cytoplasm of the cell that results in the degradation of glucose into pyruvate or lactate.

    Golgi tendon organ (GTOs)

    A tension receptor located in series with skeletal muscle.

    Graded exercise test

    see incremental exercise test

    Gross efficiency

    A simple measure of exercise efficiency defined as the ratio of work performed  to energy expanded, expressed as a percent.

    Growth Hormone

    Hormone synthesized and secreated by the anterior pituitary that stimulates growth of the skeleton and soft tissues during the growing years. It is also involved in the moblization of the body's energy stores.

    Glycogenolysis

    The breakdown of glycogen into glucose.

H

    HDL cholesterol (High density lipoprotein cholesterol)

    Cholesterol that is transported in the blood via high-density proteins: related to low risk of heart disease.

    Hemoglobin

     A heme-containing protein in red blood cells that is responsible for transporting oxygen to tissues. Hemoglobin also serves as a weak buffer within red blood cells.

    Hemosiderin

    An insoluble form of iron stored in tissues.

    High-density lipoproteins (HDL)

    Proteins used to transport cholesterol in blood; high levels appear to offer some protection from atherosclerosis.

    Homeostasis

    The maintenance of a constant internal environment.

    Homeotherms

    Animals that maintain a fairly constant internal temperature.

    Homologous transfusion

    A blood transfusion using blood of the same type but from another donor.

    Hormone

    A chemical substance that is synthesized and released by an endocrine gland and transported to a target organ via the blood.

    Hydrogen ion

    A free hydrogen ion in solution that results in a decrease in pH of the solution

    Hyperbaric Chamber

    Chamber where the absolute pressure is increased above atmospheric pressure

    Hyperoxia

    Oxygen concentration in an inspired gas that exceeds 21%.

    Hyperplasia

    An increase in the number of cells in a tissue.

    Hyperthermia

    An above-normal increase in body temperature .

    Hypertrophy

    An increase in cell size.

    Hypothalamic somatostatin

    Hypothalamic hormone that inhibits growth hormone secretion; also secreted from the delta cells of the islets of Langerhans.

    Hypothalamus

    Brain structure that integrates many physiological functions to maintain  homeostasis; site of secreation of hormones released by the posterior pituitary; also releases hormones that control anterior pituitary secretions.

    Hypothermia

    A condition which heat is lost from the body faster than it is produced.

    Hypoxia

    A relative lack of oxygen

I

    Immunotherapy

    Procedure in which the body is exposed to specific substances to elicit an immune response in order to offer better protection upon subsequent exposure.

    Incremental exercise test

    An exercise test involving a progressive increase in work rate overtime. Often graded exercise tests, are used to determine the subject's VO2  max or lactate threshold. (Also called graded exercise test)

    Indirect Calorimetry

    Estimation of heat or energy production on the basis of oxygen consumption. Carbon dioxide production, and nitrogen excertion.

    Induced erythrocythemia

    Causing an elevation of the red blood cell (hemoglobin) concentration by infusing blood; also called blood doping or blood boosting.

    Infectious diseases

    Diseases due to the presence of pathogenic microorganisms in the body.

    Inorganic

    Relating to substances that do not contain carbon.

    Inorganic phosphate

    A stimulator of cellular metabolism; split off, along with ADP, from ATP when energy is released; used with ADP to from ATP in the electron transport chain.

    Inositol triphosphate

    A molecule derived from a membrane-bound phospholipid, phosphatidylinositol, that causes calcium release from intracellular stores and alters cellular activity.

    Insulin

    Hormone released from the beta cells of the islets of Langerhans in response to elevated blood glucose and amino acid concentrations; increase tissue uptake in both

    Insulin-like growth factors

    groups of growth-stimulating peptides released from the liver and other tissues in response to growth hormone.

    Insulin shock

    Condition brought on by too much insulin, which causes an immediate hypoglycmia; symptoms include tremors, dizziness, and possibly convulsions.

    Integrating center

    The portion of a biological control system that processes the information from the receptors and issues an appropriate response relative to its set point.

    Intercalated discs

    Portion of cardiac muscle cell where one cell connects to the next.

    Intermediate fibers

    Muscle fiber type that generates high force at a moderatly fast speed of contraction, but has a relatively large number of mitochondria (type IIa).

    Ion

    A single atom or small molecule containing a net positive or negative charge due to an excess of either protons or electrons, repectively.

    IPSP

    Inhibitory post synaptic potential that moves the post synaptic membrane further from threshold.

    Irritability

    A trait of certain tissues that enables them to respond to stimuli.

    Isocitrate dehydrogenase

    Rate limiting enzyme in the Krebs cycle that inhibited by ATP and stimulated by ADP and P.

    Isokinetic

    Action in which the rate of movement is constantly maintained through a specific range of motion even though maximal force is exerted

    Isometric

    Action in which the muscle develops tension, but does not shorten, also called a static contraction, no movement occurs.

    Isotonic

    Contraction in which a muscle shortens against a constant load or tension, resulting in movement.

J

    K

      Ketosis

      acidisis of the blood caused by the production of ketone bodies when fatty acid mobilization is increased, as in uncontrolled diabetes.

      Kilocalorie (kcal)

      A measure of energy expenditure equal to the heat needed to raise the temperature of 1 kg of water 1 degree celsius.

      Kilogram-meter

      A unit of work in which 1 kg of force (1 kg mass accelerated at 1 G) is moved through a vertical distance of 1 meter.

      Kinesthesia

      A perception of movement obtained from information about the postion and rate of movement of the joints. 

      Krebs cycle

      Metabolic pathway in the mitochondria in which energy is transferred from carbohydrates, fats, and amino acids to NAD for subsequent production of ATP in the electron transport chain.

    L

      Lactate Threshold

      A point during a graded exercise test when the blood lactate concentration increases abruptly.

      Lactic acid

      An end product of glucose metabolism in the glycolytic pathway; formed in conditions of inadequate oxygen and in muscle fibers with few mitochondria.

      Lateral sac

      see terminal cisternae

      LDL cholesterol

      Form of low-density lipoprotein responsible for the transport of plasma cholesterol; high levels are indicative of a high risk of coronary heart disease.

      Lipase

      an enzyme responsible for the breakdown of triglycerides to free fatty acids and glycerol.

      Lipolysis

      The breakdown of triglycerides in adipose tissue to free fatty acids and glycerol for subsequent transport to tissues for metabolism.

      Lipoprotein

      Protein involved in the transport of cholesterol and triglycerides in the plasma.

      Low-density lipoproteins

      Form of lipoprotein that transports a majority of the plasma cholesterol; see LDL cholesterol

      Luteinizing hormone (LH)

      Also called "interstitial cell stimulating hormone"; a surge of LH stimulates ovulation in middle of menstrual cycle; LH stimulates testosterone production in men.

    M

      Major Minerals

      Dietary minerals including calcium, phosphorus, potassium, sulfur, sodium, chloride, and magnesium.

      Mast cell

      Connective tissue cell that releseases histamine and other chemicals in response to certain stimuli.

      Maximal oxygen uptake (VO2 Max)

      Greatest rate of oxygen uptake by the body measured during dynamic exercise, usually on a cycle ergometer or a treadmill; dependent on a maximal cardiac output and the maximal arteriovenous oxygen difference.

      Mesomorphy

      One component of a somatotype that characterizes the muscular form or lean body mass aspect of the human body.

      MET

      An expression of the rate of energy expenditure at rest.

      Mineralocorticoids

      Steroid hormones released from the adrenal cortex that are responsible for Na+ and K+ regulation 

      Mitochondrion

      The subcellular organelle responsible for the production of ATP with oxygen; contains enzymes for the Krebs cycle, electron transport chain, and the fatty acid cycle.

      Mixed venous blood

      A mixture of venous blood from both upper and lower extremities; complete mixing occurs in the right ventricle.

      Molecular biology

      A branch of biochemistry involved with the study of gene structure and function.

      Motor Cortex

      Portion of the cerebral cortex containing large motor neurons whose axons descend to lower brain centers and spinal cord; associated with the voluntary control of movement.

      Motor Neurons

      Efferent neurons that conduct action potentials from the central nervous system to the muscles.

      Muscle action

      Term used to describe muscle form development.

      Muscle Spindle

      A muscle stretch receptor oriented parallel to skeletal muscle fibers; the capsule portion is surrounded afferent fibers; and intrafusal muscle fibers can alter the length of the capsule during muscle contraction and relaxation.

      Muscular Strength

      The maximal amount of force that can be generated by a muscle or muscle groups.

      Myocardial infraction

      Death of a portion of heart tissue that no longer conducts electrical activity nor provides force to move blood.

      Myocardial ischemia

      A condition in which the myocardium experience an inadequate blood flow

      Mycardium

      Cardiac muscle; provides the force of contraction to eject blood.

      Myofibrils

      The portion of the muscle containing the thick and thin contractile filaments.

      Myoglobin

      Protein in muscle that can bind oxygen and release it at low PO2 values

      Myosin

      Contractile protein in the thick filament of a myofibril that contains the cross bridge that can bind actin and split ATP to cause tension development.

    N

      NAD

      Coenzyme that transfers hydrogen and the energy associated with those hydrogens; in the Krebs cycle, NAD transfers energy from substrates to the electron transport chain.

      Net efficiency

      The mathematical ratio of work output divided by the energy expended above rest. 

      Neuroendocrinology

      Study of the role of the nervous and endocrine systems in the automatic regulation of the internal enviroment.

      Neuromuscular junction

      Synaopse between axon terminal of a motor neuron and the motor end plate of a muscle's plasma membrane.

      Neuron

      Nerve cell; composed of a cell body with dendrites that bring information to the cell body to influnce neurons, glands, or muscles.

      Nitroglycerin

      Drug used to reduce chest pain due to lack of blood flow to the mycardium.

      Norepinephrine

      A hormone and neurotransmitter; released from postganglionic postganglionic nerve endings and the adrenal medulla.

      Normocythemia

      A normal red blood cell concentration.

      Normoxia

      A normal PO2.

      Nucleus

      Membrane-bound organelle containing most of the cells DNA.

      Nutrient density

      The degree to which foods contain selected nutrients.

    O

      Open-circuit spirometry

      Indirect  calorimetry procedure in which either inspired or expired ventilation is measured and oxygen consumption and carbon dioxide production are calculated.

      Organic

      Describes substances that contain carbon.

      Osteoporosis

      A decrease in bone density due to a  a loss of cortical bone; common in older women and implicated in fractures; estrogen, exercise, and Ca++ therapy are used to correct the condition.

      Overload

      A principle of training describing the need to increase the load (intensity) of exercise to cause a further adaptation of a system.

      Oxidative Phosphorylation

      Mitochondrial process in which inorganic phosphate (Pi)  is coupled to ADP as energy is transferred along the electron transport chain in which oxygen is the final electron acceptor.

      Oxygen Debt

      The elevated post-exercise oxygen consumption (see EPOC); related to replacement of creatine phosphate, lactic acid resynthesis to glucose, and elevated body temperature, catecholamines, heart rate, breathing, etc.

      Oxygen deficit

      Refers to the lag in oxygen uptake at the beginning of exercise.

      Oxyhemoglobin

      Hemoglobin combined with oxygen; 1:34 ml of oxygen can combine with 1 g Hb.

    P

      Pancreas

      A gland containing both exocrine and endocrine portions; exocrine secretions include enzymes and bicarbonate  to digest food in the small intestine; endocrine secretions include insulin, glucagon, and somatostatin, which are released into the blood.

      Parasympathetic nervous system

      A portion of the autonomic nervous system that primarily releases acetylcholine from its postganglionic nerve endings.

      Partial pressure

      The fractional part of the barometric pressure of a single gas.

      Percent grade

      A measure of the elevation of the treadmill; calculated as the sine of angle. 

      Percutaneous transluminal coronary angioplasty (PTCA)

      A ballon-tipped catheter is inserted into a blocked coronary artery and plaque  is pushed back artery wall to open the blood vessel.

      Perimysium

      The connective tissue surrounding the fasciculus of skeletal muscle fibers.

      Peripheral nervous system (PNS)

      A portion of the nervous system located outside the spinal cord and brain.

      pH

      A measure of the acidity of a solution.

      Phosphocreatine

      A compound found in skeletal muscle and used to resynthesize ATP from ADP.

      Phosphodiessterase

      An enzyme that catalyzes the breakdown of cyclic AMP, moderating the effect of the hormonal stimulation of adenylate.

      Phospholipase C

      Membrane-bound enzyme that hydrolyzes phosphatidylinositol into inositol triphosphate and diacylglycerol that, in turn, bring about changes in intracellular activity.

      Physical activity

      Characterizes all types of human movement; associated with living, work, play, and exercise.

      Physical Fitness

      A broad term describing healthful levels of cardiovascular function, strength, and flexibility, fitness is specific to the activities performed

      Pituitary Gland

      A gland at the base of the hypothalamus of the brain having an anterior portion that produces and secretes numerous hormones and a posterior portion that secretes hormones that are produced in the hypothalamus.

      Placebo

      An insert substance that is used in experimental studies to control for any subjective reaction to the substance being tested.

      Pleura

      A thin lining of cells that is attached to the inside chest wall and to the lung, the cells secrete a fluid that facilitates the movements of the lungs in the thoracic cavity.

    Q

      Quebec 10-second test

      A maximal effort 10-secound cycle test designed to assess ultra short term anaerobic power during cycling.

    R

      Radiation

      Process of energy exchange from the surface of one object to the surface of another that is dependent on a temperature gradient but does not require contact between the objects; an example is the transfer of heat from the sun to the earth.

      Reciprocal inhibition

      When extensor muscles (agonists) are contracted, there is a reflex inhibition of the motor neurons to the flexor muscles and vice versa.

      Receptor

      In the nervous system, a receptor is a specialized portion of an afferent neuron that is sensitive to a form of energy in the environment ; receptor is also a term that applies to unique proteins on the surface of cells that can bind specific hormones or neurotransmitters.

      Recommended Dietary Allowances (RDA)

      Standards of nutrition associated with good health for the majority of people. Standards exist for protein, vitamins, and minerals for children and adults.

      Relative VO2

      Oxygen uptake (consumption) expressed per unit body weight.

      Releasing hormone

      Hypothalmic hormones released from neurons into the anterior pituitary that control the release of hormones from that gland.

      Renin

      Enzyme secreted by special cells in the kidney that converts angiotensinogen to angiotensin I.

      Repetition

      The number of times an exercise is repeated within a single set.

      Residual volume (RV)

      Volume of air in the lungs following a maximal expiration.

      Respiration

      External respiration is the exchange of oxygen and carbon dioxide between the lungs and the environment. 

    S

      Sarcolemma

      The cell (plasma) membrane surrounding a muscle fiber.

      Sarcomeres

      The repeating contractile unit in a myofibril bounded by z lines

      Sarcoplasmic reticulum

      A membranous structure that surrounds the myofibrils of muscle cells 

      Satellite cells

      Undifferentiated cell found adjacent to skeletal muscle fibers. These cells can fuse with existing muscle fibers and contribute to muscle growth (hypertrophy). It may also be possible that these fibers can differentiate and form a new muscle fiber following muscle injury.

      Schwann cell

      The cell that surrounds peripheral nerve fibers, forming the myelin sheath.

      Second messenger

      A molecule or ion that increases in a cell as a result of an interaction between a "first messenger" and a receptor that alters cellular activity.

    T

      Tapering

      The process athletes use to reduce their training load for several days prior to compettion.

      Target heart rate (THR) range

      The range of heart rates describing the optimum intensity of exercise consistent with making gains in maximal aerobic power; equal to 70%-80% HR max

      Temporal summation

      A change in the membrane potential produced by the addition of two or more inputs, occurring at different times 

      Terminal cisternae

      Portion of the sarcoplasmic reticulum near the transverse tubule containing the CA++  that is released upon depolarization of the muscle; also called lateral sac.

    U

      Underwater Weighing

      Procedure to estimate body volume by the loss of weight in water; result is used to calculate body density and, from that, body fatness.

      U.S. Dietary Goals

      A series of nutritional goals to achieve better health for the American population: 58% carbohydrate; 30% fat (no more than 10% saturated fat); and 12% protein.

    V

      Vagus Nerve

      A major parasympathetic nerve.

      Variable-Resistance Exercise

      Strength training in which the resistance varies throughout the range of motion.

      Veins

      The blood vessels that accept blood from the venules and bring it back to the heart.

      Ventilation

      The movement of air into or out of the lungs (example pulmonary or alveolar ventilation); external respiration

      Ventilatory Threshold (TVENT)

      The "breakpoint" at which pulmonary ventilation and carbon dioxide output begin to increase exponentially during an incremental exercise test.

      Venules

      Small blood vessels carrying capillary blood to veins.

      Vestibular Apparatus

      Sensory organ, consisting of three semicircular canals, that provides needed information about body position to maintain balance.

      Vital Capacity (VC)

      The volume of air that can be moved into or out of the lungs in one breath; equal to the sum of the inspiratory and expiratory reserve volumes and tidal volume.

    W

      Web of Causation

      An epidemiologic model showing the complex interaction of risk factors associated with the development of chronic degenerative  diseases.

      Whole Body Density

      A measure of the weight to volume ratio of the entire body; high values are associated with low body fatness.

      Wingate Test

      Anaerobic power test to evaluate maximal rate at which glycolysis can deliver ATP.

      Work

      The product of a force and the distance through which that force moves (W= F x D).

      Work Interval

      In interval training, the duration of the work phase of each work to rest interval.

    X

      Y

        Z

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