Actin - A protein found in muscle fibers that acts with myosin to bring about contraction and relaxation.

Antagonistic - Pharmacological term used to describe a drug that blocks or shuts down a receptor, thus reducing or terminating a given biochemical response.

Basal Metabolic Rate (BMR) - Your body mass ratio, or the speed at which your resting body burns calories to provide for its basic survival needs. You can elevate your BMR and more easily achieve lean body mass through consistent exercise, and particularly through aerobic workouts.

Bray, John - American runner that came home with a bronze medal from the 1500m race, at the 1900 Olympics.

Daniels, Jack - Former research physiologist for Nike's Athletics West teams, now coaching at the State University of New York.

Eicosanoid - An autocrine hormone made by virtually every cell in the body. "Good" eicosanoids are anti-inflammatory, whereas "bad" eicosanoids cause inflammation.

Elliott, Herb - Never beaten in the mile in his entire career, Elliott ranks as one of the greatest middle-distance runners of all time. He won the 1960 Olympic 1500m in Rome in the record time of 3.35,6 - nearly 3 seconds faster than the runner-up Michel Jazy of France. Elliott won 44 races in a row between 1954 and 1960.

Morceli, Noureddine - Heading towards the year 2000, Morceli of Algeria is arguably the greatest middle distance runner of his time. To write down his world records is to tempt fate - Morceli will most likely better them between the time they are written and the time they appear in print.

Nutrient Dense Food - foods that contain many nutrients but few calories (kcals)

Training Partner - A training partner should be someone who is willing to take the time he or she is devoting to bodybuilding, and share it with you. He or she should be willing to make time in his or her schedule to workout with you, as well as offer you constructive advice and a good spot for those hard to perform, heavy lifts. It is very important that both you and your training partner care about the success and development of the pair, and make efforts to motivate and encourage each other into achieving new muscular growth. A training partner who does not have much concern over making it to the gym with you, and helping you out isn't much of a benefit to either of you. A training partner who does not offer you constructive advice isn't really helping you either, if advice is what you are looking for. Also, it is very effective if both you and your training partner are trying to achieve the same bodybuilding goals. This makes it a lot more natural for both of you to help each other with steps along the way to achieving those goals.

Vitamins - organic substances necessary for life although they do not, independently provide energy