Move into a “push up” position, though on your forearms instead of your hands. Elbows under your shoulders. Legs straight, the whole body straight head-to-foot like a “plank.” Hold for 4-7 seconds. Do not allow the hips to sag below the “plank-line.” This detail will keep you out of pain.
Remedial: Remain on your knees in “push up” position. Lower legs and feet can be relaxed on the floor. Hold for 5-7 seconds.