ballistic—Abouncing movement relying on gravity; Ballistic stretching was once thought to be the best way to improve flexibility. It has since been found that ballistic stretching can potentially tear muscles resulting in scar tissue that is inflexible.

basal metabolic rate (BMR)—The lowest rate of energy metabolism of a person at rest, 12-18 hours after eating; the lowest rate of metabolism compatible with life; Physical exertion speeds up the basal metabolic rate.

behavioral contract—A written agreement to oneself or another to behave in a prescribed manner.

beta oxidation—Process by which fat is broken down in order to generate ATP.

beta-blockers (beta-adrenergic blocking agents)—Medications that "block" or limit sympathetic nervous system stimulation; They act to slow the heart rate and decrease maximum heart rate, and are used for cardiovascular and other medical conditions. Individuals on beta blockers will have a lowered blood pressure, resting heart rate, training heart rate, and maximal heart rate.

beta-carotene—A carotenoid (pigment) found in yellow, orange and deep green vegetables which provides a source of vitamin A when ingested; This substance has been found to have antioxidant properties.

beta-oxidation—The process by which fats, in the form of Acyl-CoA molecules, are broken down in the mitochondria to generate Acetyl-CoA, the entry molecule for Kreb’s Cycle.

bias—Bias occurs when problems in study design lead to effects that are not related to the variables being studied. An example is selection bias, which occurs when study subjects are chosen in a way that can misleadingly increase or decrease the strength of an association. Choosing experimental and control group subjects from different populations would result in a selection bias.

bi-axial joint—Joint that allows motion in two planes of motion; Example, condyloid joint such as the wrist.

bilateral—Affecting two sides; see also unilateral.

biochemistry—The study of the chemistry within biological organisms.

bioelectrical impedance (BIA)—A method of determining body composition by measuring the body's resistance to electrical flow; the results of this method are greatly affected by proper hydration.

biomechanics—The study of the internal and external forces acting on the body and the effects produced by these forces; the study of the mechanical aspects of physical movement, such as torque, drag, and posture, that is used to enhance athletic technique.

biotechnology—"Applied biology", the application of biological knowledge and techniques to develop products. It may be further defined as the use of living organisms to make a product or run a process. By this definition, the classic techniques used for plant and animal breeding, fermentation and enzyme purification would be considered biotechnology. Some people use the term only to refer to newer tools of genetic science. In this context, biotechnology may be defined as the use of biotechnical methods to modify the genetic materials of living cells so they will produce new substances or perform new functions. Examples include recombinant DNA technology, in which a copy of a piece of DNA containing one or a few genes is transferred between organisms or "recombined" within an organism.

bi's—Slang for biceps brachii muscle, located at the front of the arm.

blind (single or double) experiment—In a single blind experiment, the subjects do not know whether they are receiving an experimental treatment or a placebo. In a double blind experiment, neither the researchers nor the participants are aware of which subjects receive the treatment - until after the study is completed.

blood doping—A technique that consists of giving a blood transfusion to add red blood cells to increase the oxygen-carrying ability of the blood; An athlete using this technique will usually have blood drawn and stored. Once the athlete’s blood levels have returned to normal, adding back in the removed red blood cells gives the athlete an increased number of red blood cells. It is illegal in most competitions. Risks include blood coagulation in the arteries presenting a risk of death. Blood doping has been suggested in the deaths of some elite endurance athletes.

blood glucose—Blood glucose (blood sugar) refers to sugar in the form of glucose. The blood sugar level in humans is normally 60 to 100 milligrams per 100 milliliters of blood; it rises after a meal to as much as 150 milligrams per 100 milliliter of blood, but this may vary.

blood pressure—The force exerted against heart and blood vessel walls by passing blood; When a blood pressure reading is taken, the systolic over diastolic value is determined. Systolic pressure is primarily caused by the heartbeat or contraction. The diastolic pressure is taken when the heart is filling with blood between beats. Blood pressure values vary appreciably depending on age, sex, and ethnicity. A typical adult reading may be 120mm Hg over 80mm Hg, stated 120 over 80. Blood pressures above 140 over 90 at rest are considered high; see diastolic and systolic.

blood—Blood is the fluid which circulates through the heart, arteries, veins and capillaries. It is composed of red blood cells, white blood cells and blood platelets, and an interstitial fluid called plasma. It derives its reddish color from the iron within the hemoglobin. Blood functions to provide nutrition and respiration for tissues located far from food and air supplies. It also transports waste from the tissues to the excretory organs. Blood provides chemical and thermal regulation to the body and helps prevent infection by transporting antibodies.

BMR (basal metabolic rate)—See basal metabolic rate.

body composition test—A test or tests used to determine percentage of body fat; Examples, underwater or hydrostatic, skinfold, anthropometric, or electrical impedance.

body composition—The proportion of body fat to fat free mass.

body mass index (BMI)—A relative measure of body weight (in kg) to body height (in meters squared) for determining degree of obesity; BMI’s over 30 are considered obese according to U.S. standards.

bodybuilding—Training with the specific goal to enhance musculature and physical appearance.

bodyfat—Term often used to describe the percentage of fat in the body.

bone—Dense connective tissue that composes the skeleton; Bones may be strengthened through proper exercise—typically through exercise that requires weight bearing on the bone.

bonked—Slang term meaning to run out of energy.

Borg’s scale (of perceived exertion)—A scale using perceived exertion with a numerical code to determine the level of exertion; The scale helps participants tune into their bodies since metabolism and functions can vary from day to day. There are two versions of the Borg scale, classical, based upon a scale of zero to 20 and the modified Borg scale, which is more common, based upon a scale of zero to 10.

Bovine spongiform encephalopathy (BSE)—(mad cow disease) Bovine spongiform encephalopathy, or BSE, is also known as "mad cow disease." It is a rare, chronic degenerative disease affecting the brain and central nervous system of cattle. Cattle with BSE lose their coordination, develop abnormal posture and experience changes in behavior. Clinical symptoms take 4-5 years to develop, followed by death in a period of several weeks to months unless the affected animal is destroyed sooner.

brachial artery—The main artery of the arm, located in the upper inside of the arm; In CPR (cardiopulmonary resuscitation), the brachial artery is used for palpating the pulse of infants.

bradycardia—Slower than average resting heart rate, due to the increased efficiency of the heart through aerobic conditioning in an athlete; A heart rate of less than 60 beats per minute is typical of bradycardia. Slow HR is considered to mean poor health for a non-athlete, but a sign of cardiac fitness for an athlete.

branched chain amino acids (BCAA) - The essential amino acids valine, leucine, and isoleucine. The "branched chain" refers to the chemical structure of these amino acids. Thought to be important because they can be used to generate glucose for use as energy.

branched chain amino acids (BCAA)—The amino acids L-leucine, L-isoleucine and Lvaline, which have a particular molecular structure that gives them their name; BCAAs comprise 35 percent of muscle tissue. BCAAs may be burned as fuel during highly intense training, and at the end of long-distance events, when the body recruits protein for as much as 20 percent of its energy needs.

brewer’s yeast—A non-leavening yeast used as a nutritional supplement for its rich content of vitamins (particularly B complex), minerals and amino acids.

bromelain—A proteolytic enzyme (protein-splitting enzyme) found in pineapples; it is thought to reduce inflammation and edema and accelerate tissue repair; fresh pineapple is the best source.

bronchioles—The smallest tubes that supply air to the alveoli (air sacs) of the lungs.

bronchitis—Acute or chronic inflammation of the mucous membranes of the bronchial tubes; see chronic obstructive pulmonary disease.

bronchodilators—Drugs that are designed to expand the bronchial tubes by relaxing the constricted bronchial smooth muscle, used by asthmatics; Example, Proventil.

buffed—Slang term used to describe someone with good muscle size and definition.

Bulimia Nervosa—An eating disorder characterized by rapid consumption of a large amount of food in a short period of time, with a sense of lack of control during the episode and self-evaluation unduly influenced by body weight and shape. There are two forms of the condition, purging and non-purging. The first type regularly engages in purging through self-induced vomiting or the excessive use of laxatives or diuretics. Alternatively, the non-purging type controls weight through strict dieting, fasting or excessive exercise.

Bulimia nervosa—An eating disorder also known as "binge and purge"; A bulimic person often overeats then induces vomiting and/or the use of diuretics or laxatives. Bulimia is a disorder that can become life threatening. This condition requires medical intervention; treatment involves psychotherapy.

bulking up—Slang referring to the process of gaining body weight by adding muscle, bodyfat or both.

bulk—Slang referring to muscle mass achieved through strength training.

bursa—A lubricating and protective sac located between certain connective tissue, i.e., between tendon and bone, tendon and ligament, or other structures, usually in the vicinity of joints; (Pl. bursae).

bursitis—The inflammation of a bursa; occurs most often in the knees, hips, shoulders, and elbows.