Burn – As in “going for the burn” In endurance exercise, working muscles until lactic acid build-up causes burning sensation.
Cool Down - Moderate then light activity, normally followed by stretching.
Easy Set - Exercise not close to maximum effort, as in a warm-up.
Forced Repetitions - Assistance to perform additional repetitions of an exercise when muscles can no longer complete movement on their own.
Hard Set - Perform a prescribed number of repetitions of an exercise using maximum effort.
Repetition - One complete movement of an exercise.
Rest Interval - Pause between sets of an exercise, which allows muscles to recover partially before beginning next set.
Set - Fixed number of repetitions. For example, 10 repetitions may comprise one set.
Super Set - Alternating back and forth between two exercises until the prescribed number of sets is completed.
Training to Failure - Continuing a set until it is impossible to complete another rep without assistance.
Warm up - Light gradual exercises performed to get the body ready for physical activity, normally a slower version of the activity to follow. For example a light jog before a run. Often followed by stretching of the body.
Becoming aware of fitness terms makes it a lot easier when you are trying to follow along with a program. You can find hundreds more from the source page below: