I don’t know how “new” this push-up is to the fitness world but its new to me! It works your abs as well as your whole upper body. My kick-ass trainer taught me. Here are some pictures of my sister and myself doing this exercise.
You start in a push-up position ( a real push-up position, keep your knees off the floor).
Then at the top of your push-up position, bring your knee to your elbow (sounds crazy but you can do it), do this for each side.
There you go! If you are tired of the same old push-up, try doing this one!