Interval training is an excellent way to burn fat and work on cardio resistance. The HIIT (High Intensity Interval Training) bears its name for a reason and is now a key training technique.The objective of this type of session is to work out in an intense way, to shock the body and to raise the heart rate. And sometimes, a partner and a treadmill are enough to achieve effective training in this way. That's what Ryan Reynolds' coach Don Saladino proposes with this 20-minute session.The idea is simple: run one minute on the treadmill, one at a time. While one is working out, the other is recovering. Do it ten times each.Be aware that it is important to work out at a high intensity. The one-minute run should not be a simple jog, otherwise it is not effective. It is possible to vary the intervals according to the level of each person, either in 30-second or 45-second periods.