Start: Lie on your nondominant side. Support your weight with that forearm and the outside edge of that foot. Your body should form a straight line from head to ankles.
Finish: Pull your abs in as far as you can, and hold this position for 10 to 30 seconds, breathing steadily. Relax. If you can do the entire 30 seconds, 1 rep is enough, If not try for any combination of reps that gets you u to 30 seconds Then repeat on your other side.