Go for twist exercises like the Russian twist ... Put your right arm on the mat and your left hand behind your head. Crunch up in a V, getting up on your hip and butt. Keep your legs straight.

Lift your hips, forming a straight line from your feet to your head ... hands on each twist. Do 15-20 reps per side. 5.

Plank variations also strengthen superficial and deeper muscles, and adding the twist moves your trunk through rotation, working the oblique muscles. I recommend adding a variety of exercises to ...