The most popular form of the Plank is the Forward Plank exercise (shown above) which usually involves weight bearing through the forearms and toes, with the body maintained in a horizontal position elevated above the ground.
Muscles used in Forward Plank
The Forward Plank exercise involves a range of different muscle groups in the body working to hold the body above the ground.
The main muscle groups used during Plank are the core muscles that surround the trunk; the abdominal muscles and spinal muscles. Secondary muscles are also involved in stabilizing or holding the body in position during Forward Plank and these include muscles around the shoulder girdle, chest, middle back, thighs and calf.
Starting Position: Lie on your stomach on an exercise mat or floor with your elbows close to your sides and directly under your shoulders, palms down and fingers facing forward. Engage your abdominal/core muscles. It should feel like you are tightening a corset around your ribs, waist and lower torso. Contract your thigh muscles to straighten your legs strongly and flex your ankles, (tucking your toes towards your shins).
Upward Phase. Slowly lift your torso and thighs off the floor or mat. Keep your torso and legs rigid. Do not allow any sagging in your ribcage or low back. Avoid hiking your hips into the air or bending the knees. Keep the shoulders away from the ears (no shrugging). The shoulders should be directly over your elbows with your palms facing down through the entire exercise. Continue to breathe, keeping the abdominals strong while holding this position. Try holding this position for 5 seconds or more.
Downward Phase: Keep the torso and legs stiff as you slowly and gently lower your body back towards the mat or floor.
If you experience any pain in the low back with this movement, stop the exercise immediately and consult with your doctor.