Looking for a way to perfect your plank form? Two of the biggest mistakes people make when planing is elevated shoulders (shoulders by your ears) or shoulder blades pinching together (collapsing in your upper body). Those two mistakes lead to increased stress in your low back and increased weight bearing on your wrists. By engaging your serratus anterior you will be able to find width between your shoulder blades and find better engagement of your back and shoulder muscles taking undue pressure of your wrists and lumbar.
The rolling plank variation starts you off with strong engagement of your serratus anterior by applying strength isometrically on the ground/mat outwards (isometric exercise refers to an exercise where a muscle length does not change during contraction, aka no movement occurs during the exercise).
1) Start by placing your forearms parallel to one another, elbows facing outwards. Make sure your elbows are directly beneath your shoulders.
2) Lift to plank position by engaging your core, back, shoulders, triceps, and quadriceps. Keep you body in one long line!
3) Apply pressure on the mat outward, beginning to feel your serratus work and pull your shoulders wide on your back. Hold the center plank for 20 seconds.
4) Keeping your shoulder stability roll onto your right side, stacking your hips, pivoting your feet and opening your left arm up to the ceiling. Hold right side plank for 20 seconds.
5) Roll back to center. Hold for 20 seconds.
6) Turn to the left. Hold for 20 seconds.
7) Return to center. Hold for 20 seconds. Rest. REPEAT.
(you can do this exercise in each position for as long as you can hold with good form; 5 seconds, 10 seconds, 30 seconds, etc.)