Who needs a treadmill? With this workout, from Wilke and Gallagher, all you need is your body, a little floor space, a towel to mop up with. The key: Don't take a break. Go as hard as you can in 15 minutes, completing the maximum rounds possible.
Workout:
15 push-ups: Keep the elbows snug to the body as you lower your chest to the ground and then raise back up.
15 squats: Stand with feet hip-width apart, and squat down as low as you can, keeping shoulders up and back flat. Press through heels to stand.
15 cross-body mountain climbers: Start in a plank position, keeping your body in line from your head to your toes. Then, lift your right leg off the ground and pull your knee toward your left elbow. Return to the stating position and repeat on your left side for one rep.
15 flutterkicks: Lie face-up on the ground with your hands resting under your glutes. Keeping your body flat and your abs braced, raise your feet a few inches on the ground and kick up and down with both feet, as if you were swimming in a pool.
