Sets: A single exercise that is completed multiple times, with a rest break in between.

Circuits: A collection of exercises, completed one after the other, as many times as possible. Circuits are usually either time-based or lap-based.

Lap-Based Circuit: A circuit that has an end point which is dictated by an allocated number of laps. There can be rest breaks between exercises or laps.

Time-Based Circuit: A circuit that has an end point which is dictated by an amount of time. There can be rest breaks between exercises or laps. 

1RM (One-Rep Max): Is the maximum amount of weight you can lift for one repetition of an exercise.

RPE: Stands for “Rate of Perceived Exertion” or how hard an exercise feels. A 10/10 RPE would therefore be maximum effort.