set: A group of consecutive repetitions in a strength training program.

Spinning: A popular group studio cycling program invented by ultra-distance cyclist Johnny G. and licensed by Schwinn, which manufactures the bikes used in these classes.

stair-climber: A cardiovascular machine that has two foot plates you pump up and down to mimic the action of climbing stairs. Also called a stepper.

stationary bike: A cardiovascular machine that comes in two styles: upright bikes and recumbent bikes.

step aerobics: A choreographed routine of stepping up and down on a rectangular, square, or circular platform.

strength training: A type of workout that uses any combination of weight machines and free weights (dumbbells and barbells) to build muscle strength.

stride frequency: The number of strides that a runner takes over a certain time period.

studio cycling: Group exercise classes that are taught on stationary bicycles.