Adding dynamic movements to a plank is a great way to progress from an isometric core training routine to a more functional core stability training regimen. Dynamic movements perturb your center of mass, forcing your core to stabilize as you move. Additionally, arm and leg movements away from your center of mass increase the lever arm against which your core must stabilize.
In the first exercise, we demonstrate a primitive crawling pattern popularized by FMS. In the second exercise, we demonstrate the popular bird dog exercise.
For all these dynamic plank movements, DO NOT LET THE TRUNK OR PELVIS rotate or move. Brace your core, and make controlled movements with your extremities while being kinesthetically aware of your spinal position. Notice how I use a foam roller on my back to stay level, if I don't, the foam roller will roll off!