HiiT stands for ‘High Intensity Interval Training’ and is hands-down o ne of the best ways for you to burn fat without causing your body to catabolize its own muscle tissue.

HiiT features three different high-intensity routines that are about 30 minutes in length, making these workouts perfect to use on days when you’re short on time.

The first ‘HiiT’ workout is 30/30 at 38 minutes, and as the title suggests, each interval is divided into 30-second high-energy plyo reps, followed by equal 30-second rests for a total of 16 tough intervals.

The second ‘HiiT’ workout is 40/20 at 29 minutes, and it includes 16 intervals. Each is divided into 40-second high-energy plyo reps, followed by 20-second rests. Three additional one-minute breaks are spread throughout the program.

The third ‘HiiT’ workout is Double Wave Pyramid at 30 minutes. In this workout, two rounds of intervals are separated by and only one-minute rest. Each round is followed by a pyramid cycle of nine intervals. The first set starts with a 20-second interval, and works up to the top of the pyramid with each interval increasing by five seconds. It then works back down the pyramid, decreasing each interval by five seconds.