The Corkscrew Plank exercise works your shoulders, back, chest, triceps, abs and butt.
The next move, you're gonna get into a push-up position but I want you to take one leg and twist it down to where you're completely sitting on your hip. You're going to use your upper body to lift up and extend the leg out to the side. I don't want it too high because I wanted you to feel through your abs. So drop and lift, drop and lift. You can repeat up to 15 to 30 of these on each side depending on your ability to keep proper form.