You may not head the gym in hopes of building a sexy serratus anterior, but you should. This small muscle, located at the sides of the chest and under the armpits, is intrinsic to the action and support of your shoulder blades. Building it helps fill out your chest evenly and, perhaps more importantly, contributes to healthy shoulder function.
The standard push-up works the anterior serratus somewhat, but a few tweaks to your basic form can help you really amp up the activation of this muscle.
The push-up plus isn't that different than a standard push-up, but it does wonders for the small serratus anterior muscle. A study published in a 2004 issue of the American Journal of Sports Medicine showed that the push-up plus demonstrated serious activation of the serratus anterior.
How To: Get into the top of a standard push-up with your abs drawn in. Bend your elbows to lower your chest to nearly touch the floor. As you rise back up, push your upper back up as you broaden your shoulder blades. Hold this action for a count or two to deepen the activation of the serratus anterior. This final movement is the "plus" part of the push-up and is relatively slight, but effective.
Make It Even More Effective
The lift of the upper back at the top of the push-up motion can be incorporated in almost any variation of the push-up. Modified push-ups against a wall or on your knees also effectively activate the serratus anterior and are especially appropriate in the beginning stages clinical shoulder rehab situations, reported a 2004 study by the University of Minnesota.
If all push-up variations are out of reach for you because of shoulder or elbow pain, come to a plank position on your forearms and push the upper back up to activate the serratus anterior.
Once you've mastered the basic push-up plus on the floor, it's time to increase muscle activation to further strengthen the serratus anterior. A push-up plus performed with your hands on a stability ball further increases serratus anterior muscle activation, according to a study published in 2013 in the Journal of Physical Therapy Science.
The serratus anterior isn't usually the star of a workout; it's typically relegated to the role of assistant in the incline shoulder raise or a twisting chest press. However, when the chest and back become disproportionately strong in comparison to the serratus anterior, it puts you at risk for shoulder impingement.
A weak serratus anterior may also negatively affect your posture. Because the muscle supports your shoulder blades, a weak serratus anterior can mean slumping shoulders and a rounded chest, even if you're muscular and strong. Include this slight variation of the push-up to keep this muscle healthy and strong.