Squatting, lunging, pumping, skipping, hopping, pressing; you name it, circuits has it! Circuit training is a form of body conditioning or resistance training using high-intensity aerobics. An exercise ""circuit"" is one completion of all prescribed exercises in the program. When one circuit is complete, you will start the first exercise again for the next circuit. The time between exercises in circuit training is short, often with rapid movement to the next exercise.