Recovery Index:
The sum of three 30-second heart-rate recoveries counts after a step test.

Relative Body Fat:
The proportion of fat tissue in the body often expressed as a percentage of body weight (percent of body fat).

Repetition One complete movement of an exercise.

Rep Out Repeat the same movement over and over until you are unable to do anymore.

Reps Abbreviation for REPETITIONS.

Rest Interval Pause between sets of an exercise, which allows muscles to recover partially before beginning next set.

Rest Pause Training Training method where you press out one difficult repetition, then replace bar in stands, then after 10-20 second rest, do another rep, etc.

Ripped Slang meaning extreme muscularity.

Roid Slang for ANABOLIC STEROID. Slow Twitch Muscle cells that contract slowly are resistant to fatigue and are utilized in endurance activities such as long-distance running, cycling or swimming