This one move builds better biceps AND a tighter tush

Curtsy lunge with curl: You're a pro when it comes to lunges—backward, forward, side to side—you've mastered them all. So what now? Whether you're looking for an added challenge or you're just a compulsive multi-tasker, you should try showing your biceps a little love on leg day with this move.

(Get more total total-body workouts from Women's Health's Look Better Naked DVD.)