HIIT: High-intensity interval training. Short, intense work periods provide improved athletic capacity and metabolism.

TRX®: Total Body Resistance Exercise. Refers to yellow and black straps you might see anchored to the wall or a rack used for bodyweight and suspension training.

Functional training: Compound or multi-joint exercises or movements used to prepare the body for everyday life.

Group fitness: Mode specific, often choreographed classes such as indoor cycling, Zumba, aqua, or group strength training, where the instructor leads by demonstrating exercises. Group training: Smaller, semi-private group in which the trainer leads by coaching. Group training often occurs on the main, public floor of a fitness center.

Circuit: Performing a series of exercises, moving from one exercise to the next with little or no rest.

Super set: Two exercises performed in alternating fashion.

Intervals: A set amount of time in work, followed by a set amount of time in rest.

Kettlebell: Cast iron weight equipment in the shape of a bell. Used for swings, lifts and carries.

Rep: One complete motion of an exercise.

Set: A group of consecutive repetitions.