Fitness Dictionary
by Justin French

-B-

Ballistic
A bouncing movement. Movement due to momentum rather than muscular control. Ballistic stretching involves "throwing" a body part in order to stretch a joint beyond the range of motion attainable through controlled muscular contraction such as when "bouncing" at the bottom of toe-touches. It is an effective technique for causing injury to connective tissue, which can reduce flexibility rather than enhance it.

Barbell
A straight or curved bar typically five to seven feet in length designed to have weights placed on the ends. A standard seven-foot olympic (takes plates with 2" holes) barbell weighs either 44 pounds (20 kilograms) or 45 pounds, not including collars.

Basal Metabolic Rate
The rate at which the body burns calories while awake but at rest (usually measured in calories per day).

Bench
A piece of gym equipment with a horizontal or mostly horizontal top surface designed to be sat upon or lain upon while performing an exercise. Benches may be flat, inclined (angled so that an exerciser lying on the bench would have his head higher than his hips), or declined (angled so that an exerciser lying on the bench would have his head lower than his hips).

Bench Press
A common exercise for the chest and triceps. View example

Bent Over Row
An exercise for the back, lats and biceps. View example

Beta Agonist
A beta-agonist or beta adrenoceptor agonist is a drug or chemical that partially mimics the effects of epinephrine, primarily targeting the beta adrenoceptors which accelerate heart rate and increase blood pressure (beta-1), dilate bronchial passages (beta-2), and release fatty acids from fat cells into the blood stream (all beta receptors). The most commonly encountered beta agonists are asthma drugs such as ephedrine and albuterol which target the beta-2 receptor.

Biceps Brachii
The familiar "make a muscle" muscle that flexes the elbow joint. Additionally, the biceps supinates the forearm and helps raise the upper arm at the shoulder.

Biceps Femoris
The large, two-headed muscle on the back of the thigh. Contracting this muscle flexes the knee and also extends the hip (only one head of the muscle originates above the hip joint and contributes to this movement).

Bio-Electrical-Impedance
BEI. The resistance of a path through the body (typically measured between the feet and/or hands), most often used to estimate bodyfat percentages because fat conducts electricity more poorly than muscle.

Biological Value
The actual value of a food upon digestion which can differ greatly then the value assigned to it outside the body.

BMI
see body mass index

BMR
see basal metabolic rate

Bodybuilding
Lifting heavy objects that don't need to be moved in an effort to increase muscle size, definition and symmetry.

Body Fat
Potential energy! Tissue comprised of fat cells that store energy. Body fat is generally expressed as a percentage of total body weight or total body mass.

Body Mass Index
BMI. Yet another way of approximating body composition for use in large-scale medical studies and for health reports to refer to in the popular press. This particular measure is calculated by dividing your mass in kilograms by the square of your height in meters. While such simplistic measures are useful for large statistical samples of the general population, their value is highly limited for individuals, particularly athletes who can be very healthy and have low bodyfat percentages despite having a higher-than-recommended BMI.
a web-based BMI calculator, bodyfat estimator, and other tools may be found at Phys' health calculator page

Box Squat
A variation on the squat performed with a bench, box, or other solid object under the lifter that stops the decent at the bottom. This can cause excessive compression of the spine and possibly lead to injury.

Brachioradialis
Hmmm... good question, I'll find out.

Branched Chain Amino Acids
BCAA's. The amino acids L-leucine, L-isoleucine, and L-valine, so named because of their branched structure. They are a major constituent of muscle tissue and are preferentially consumed during intense exertion or dieting.

Brown Fat
A type of fat cell with a greatly increased density of mitochondria and a much greater blood supply than ordinary "white" fat. Besides being able to store fat, brown fat cells can convert calories directly into heat through a process known as non-shivering thermogenesis. Brown fat is used by mammals to maintain body temperature and to expend excess calories that are consumed but not stored as fat.

Bulking Up
To gain size and mass, preferably (but not always) mostly or entirely muscle and other lean tissue.

Bumper Plate
A weight plate (almost always olympic) with a rubber outer rim to reduce damage to the floor (and the plate) in case it is dropped. These are most commonly used in olympic lifting where very heavy weights are lifted overhead.