This article is from the Fitness FAQ, by Jeff Gleixner (glex@cray.com) with numerous contributions by others.
Aerobic: Occurring only in the presence of oxygen. Your muscles need
to work in an aerobic state to provide FAT burning qualities.
Anaerobic: Occuring only in the absence of oxygen. Your muscles need
to work in an anaerobic state to provide hypertrophy.
Barbell: A bar, usually over 3' long, with a place on each end where
weights/plates are placed. Usually used with two hands.
Carbohydrate (carbs): 4 calories per gram. Recommendations are 50-70% of
your total caloric intake should come from carbohydrates. Common
sources are bread, bagels, potatoes, oatmeal, cereals, sugars, etc.
Circuit Training: Going from one exercise to another until the whole
body is worked, then taking a short rest and doing the circuit
again. Provides minimal aerobic benefit, used primarily to shorten
the workout.
Dumbbell: A bar, usually about 1' long with plates on each end. Usually
used with one hand.
EMS: Electro Muscle Stimulation. Provides only therapeutic effects no
hypertrophy.
fast Twitch muscles (type II): Strength fibers. Responsible for strength
and explosiveness and hypertrophy.
FAT (fat): 9 calories per gram, round up to 10 to make the math easier and to
give even more emphasis on how many FAT calories that makes up
a certain food . Recommendations are 10-20% of your total caloric
intake should come from FAT. Common sources are nuts, dairy products,
chocolate, ice cream, egg yolks, red meat, etc.
Hardgainer: Not being genetically predispositioned to put on muscle.
Hyperplasia: The splitting of a muscle fiber into multiple fibers.
Hypertrophy: This refers to actual growth of a given fiber.
Periodization/Cycling: Varying the weights used or the reps used over
a certain period of time. Usally cycled through endurance, mass,
and strength cycles.
Plate: The weight that's placed on a barbell. "Put on a 25-pound plate".
Positive: The part of the activity where the weight is moving against
gravity. The actual pushing or pulling of a weight or object.
Pronated : Palm down or thumbs pointing toward each other.
Protein: 4 calories per gram. Reccommendations are 10-20% of your total
caloric intake should come from protein. Common sources are fish,
chicken, egg whites, milk (skim), beans, etc.
Pyramid: Sets, for a certain muscle, are performed by adding weight and
doing less reps. Others prefer starting with a heavy weight
and lower the weight every set.
Rep: Doing an activity through it's full range of motion.
Set: A group of reps. Usually the activity is started and performed
for a certain number of reps then it is stopped and you rest.
This is one set.
Slow Twitch (type I): Endurance muscle fibers. They provide the stamina
needed for long duration activities and don't hypertrophy very much.
Step: Basically a platform, usually made of plastic, that's anywhere
from 3-12" high. It takes more energy to step up on a platform.
The higher the platform the harder an activity will be and the
greater the chance for injury.
Supinated : Palm up or when the thumbs point are away from the body.
Volume Training: Doing a lot of sets, usually 15-25, per body part.
 
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