- For your lowest interval, begin with marches. Pick up your knees and engage your core with your shoulders back.
- For the medium level interval, start jump roping. Stay on your toes in order to work your calves.
- For the advanced and highest level interval, do fire feet. Stand with your feet slightly wider than hip-distance apart. With your knees slightly bent, begin to run in place as quickly as you can.
- Other alternatives for the highest level interval are high knees or sprints.
-Eliza, University of Massachusetts, Amherst