- Frogger: This plank-to-squat move seems simple, but you'll feel it as you do your 30-second bursts. Begin in a plank position. Jump your feet to the outside of your hands, coming into a deep squat and keeping your hands on the floor, then jump back to plank. Repeat in a quick succession (above).
- Running up stairs. Run up and down the stairs at home or at your office — you'll get the added bonus of a toned backside.
- Walking lunges. These lunges help you develop balance while strengthening your core and lower body. Do these briskly, but make sure your form stays correct to prevent knee or ankle strain. Here's how to do a perfect walking lunge.
- High knees: Run in place while engaging your core and pumping your arms. The goal should be to keep your knees high and maintain an upright posture as you do your speed bursts.