Side Jackknifes

Lie on your left hip, with your legs nearly straight and slightly raised off the floor. Also raise your torso off the floor, with your left forearm on the floor for balance.
 
Hold your other hand behind your right ear, with your elbow pointed toward your feet.
 
Lift your legs toward your torso while keeping your torso stationary. Pause to feel the contraction on the right side of your waist. Then slowly lower your legs and repeat.
 
Finish the set on that side, then lie on your right hip and do the same number of repetitions.