palpitation—A pounding or racing of the heart; associated with emotional responses or with certain heart disorders.

patella—Kneecap.

pecs—Slang for pectoral muscles of the chest.

peptide bond - Bond between two amino acids.

perceived exertion—The subjective perception of exercise effort; see Borg’s scale (of perceived exertion).

percent body fat—Refers to the ratio of fat to lean tissue and muscle mass.

periodization—The alternating of training intensities over periods of days, weeks, months, or years.

peripheral vascular resistance—Impedance of blood flow in the peripheral (farthest from the center) blood vessels.

phosphagens—High-energy phosphate molecules that can be broken down for immediate use by the cells; adenosine triphosphate (ATP) and creatine phosphate (CP).

physical fitness—A set of attributes that relates to the ability to perform physical activity.

physiological adaptations—Changes that occur as a result of stimuli to the various systems involved in life functions (muscular, cardiovascular, skeletal, etc.)

physiology—The study of essential life processes, functions, and activities.

phytochemical—Phytochemicals are substances found in edible fruits and vegetables that may be ingested by humans daily in gram quantities and that exhibit a potential for modulating the human metabolism in a manner favorable for reducing risk of cancer. (see functional foods)

placebo—Sometimes casually referred to as a "sugar pill," a placebo is a "fake" treatment which seems identical to the real treatment. Placebo treatments are used to eliminate bias that may arise from the expectation that a treatment should produce an effect.

plantar flexion—Ankle movement pointing toes toward ground, or away from body.

plantar—Of or pertaining to the sole of the foot.

plateau—A point in training at which one no longer sees improvements from one’s current exercise routine; maintaining one’s muscular size, strength, and/or athletic performance in spite of increased training efforts.

plates—Lead plates of weight used in resistance training.

plyometric exercises—The sudden eccentric loading and stretching of muscles followed by their forceful concentric contraction; the sudden stretch causes a forceful contraction, i.e., jumping from a bench to the ground, then jumping back onto the bench.

PNF stretching—See proprioceptive neuromuscular facilitation.

polypeptide—Chain of amino acids.

polyunsaturated fats—A bond of at least 3 fatty acids with two or more points of unsaturation; polyunsaturated fats are found in raw nuts, some vegetables and grains; preferable to saturated fats.

positive (concentric)—The part of a resistance exercise when the exerciser lifts the weight by pushing or pulling.

posterior—Back portion or toward the back; Example: a tendon located behind the inner ankle is the posterior tibialis tendon.

post-menopausal—Pertaining to the period of time after menopause.

power—The speed at which one can apply a force over a given distance; Power = Force x Distance/Time.

premenopausal—Pertaining to the time before menopause.

prevalence—The number of existing cases of a disease in a defined population at a specified time.

prime mover—A muscle or set of muscles that acts directly to bring about a specific movement; most body movements are a combined action of many muscles.

progressive overload—Incremental increases of the workload, frequency, intensity, duration, load prescription, interval time, number of repetitions, or number of sets.

pronation—Rotation of a limb toward the midline of the body; turning the palm downward or flattening the arch of the foot; Pronation is a common foot problem which could predispose an athlete to injury; see orthotics.

prone—Lying face down in a horizontal position.

proprioception—Awareness of the body’s relative position to the outside world; Information from proprioceptors and the eyes is interpreted by the brain to allow postural alignment and balance to be maintained; see proprioceptor.

proprioceptive neuromuscular facilitation- (PNF)—A technique for increasing flexibility; the muscle is stretched, isometrically contracted, then stretched farther.

proprioceptor—A sensory receptor that aids in judging body position and changes in position; Proprioceptors are located in muscles, joints, tendons and sensory hair cells in the balance organ of the inner ear; see proprioception.

prospective study—Epidemiological research that follows a group of people over a period of time to observe the potential effects of diet, behavior and other factors on health or the incidence of disease. In general, this is considered a more valid research design than retrospective research.

protagonists—Muscles working together to create a certain movement.

protein—Chemically, a protein is a complex nitrogenous compound made up of amino acids in peptide linkages. Dietary proteins are involved in the synthesis of tissue protein and other special metabolic functions. In anabolic processes they furnish the amino acids required to build and maintain body tissues. As an energy source, proteins are equivalent to carbohydrates in providing 4 calories per gram. Proteins perform a major structural role in all body tissues and in the formation of enzymes, hormones and various body fluids and secretions. Proteins participate in the transport of some lipids, vitamins and minerals and help maintain the body's homeostasis.

proteins—Food substances formed of amino acids; The function of proteins is to build and repair tissue for hormone production and enzyme function. Proteins consist of nitrogen, oxygen, carbon and hydrogen.

protraction—Scapular abduction.

proximal—Anatomical term meaning closer to the trunk of the body; nearest the point of attachment or nearest the center of the body.

pulmonary—Affecting the lungs or lung tissue.

pumped—Slang term used to describe the tightness in a muscle made large through exercise; the pumped sensation results from blood engorgement and lactic acid accumulation in the exercised muscle.

pumping iron—Slang for lifting weights; a phrase used since the 1950s.

pyruvic acid/pyruvate—End product of the glycolytic pathway; three-carbon metabolite that in aerobic conditions becomes acetyl Co-A and enters the Kreb’s cycle, or, under anaerobic conditions will become lactic acid.