This is a quick workout that’s great if you’re in a time crunch but you still want to sweat and feel the burn. I love running, but it’s too much impact on my joints to do religiously. I run a lot when I have time off, but I limit my runs to only this workout if I’m in season.  I find that shorter and more intense runs are easier on my joints as opposed to long distance runs. Plus, high intensity interval training workouts are a great form of cardio to incorporate into your workout regimen. Warming up properly is really important before sprinting at such a high speed, so I make sure I do some gentle stretching beforehand and I warm up on the treadmill with 5 minutes of speed walking. For the intervals, I use a 30:30 setup. Meaning, I alternate sprinting at full capacity for 30 seconds with resting for 30 seconds. For the rest periods, I jump to the side of the machine and hop back on for the work period. Make sure you are careful getting back on the treadmill, as it will still be moving really fast. On the chart, the column that says “rest” serves as an instruction to step to the side of the moving treadmill during the rest period.