This is a great exercise because not only are you over loading your chest and triceps with the push up motion, but they force you to up your cardio as you hop your feet in and out throughout the exercise. Starting in a push up position, you must maintain your form (back flat, abs engaged, butt down, shoulders over wrists) as you lower down into a push up while hopping your feet apart about two feet. Push yourself up and hop your feet together as you make your ascent. Make sure your spine stays straight throughout the exercise; if you feel as though your back is swaying up or down, stop. Try to keep the hopping of your feet and the push up action in sync. Start with 5-10 reps. Aim for 1 set, then after a week or so progress to 2 sets of 5-10, working your way up to 2 sets of 10-15 reps.