One of my all time favorite workout to do are HIIT workouts. HIIT means high intensity interval training. HIIT workouts get your heart rate up and then bring it back down and you repeat these cycles for maximum calorie burn-age. HIIT’s are mainly done running/on the treadmill, rollerskating, biking, and walking. This workout can be repeated as many times as wanted.

Start off with a five minute warm up at speed 3.5 and 3 incline
Do one minute at 8 speed
One minute at 4 with incline 2
One minute at 3.5 with incline 6 increasing by 2 incline each time you repeat this.
*Modify speeds/incline to fit your fitness level