This workout is intense. 20 seconds of intenseactivity followed by 10 sec. of rest. High intensity workout comprised of very intense work are great because with this type of training you can boost metabolism for 24 hours post-exercise. Why? Because of the higher demand on you body. In addition, you can burn more total calories because of an increase in resting metabolism. If you’ve never done this type of exercise before, start with a few rounds (2-5 min total) and build from there. Remember, always warm up and cool down to avoid injury. Have fun with it.