Small muscles: they’re out of sight, out of reach, hard to name, and sometimes even more difficult to understand. But in spite of keeping a low profile, these little guys are serious behind-the-scenes heroes that play crucial roles in health, fitness, strength, balance, speed, posture, and agility. We’re going to shine the spotlight on our favorites, one by one. Today’s star: the serratus anterior.

Small Movements, Big Deal — The Need To Know

The serratus (suh-RAY-tus) anterior is a fan-shaped muscle that wraps around the side of the ribcage, from the inside edge of the shoulder blade to the ribs themselves. On individuals with highly developed serrati and low body fat, the muscles will look basically like a small set of gills on the side of the chest. The action of the serratus anterior is to anchor the shoulder blade. When it contracts, the serratus pulls the shoulder blade flush and forward on the ribcage (it’s a vital component of any good bear hug). Imagine standing behind someone and placing both hands low on their shoulder blades, then sliding the hands apart slightly, around the ribs to the armpits. Retraction pulls the shoulder blades back, causing the chest to appear to stick out. The serratus also plays an important role in overhead pressing movements, helping stabilize the scapula as it rotates upward. It’s a movement of inches— or even fractions of an inch— so why the big fuss? Well, the serratus is the bridge that any force traveling from the body to the arm must cross (imagine a pitcher whipping his body around to throw a fastball) and vice versa (like a pushup). The arm’s movement and stability rely on a network of muscles that anchor it to the shoulder blade and the shoulder blade to the body. At the base of this chain is our friendly neighborhood serratus.

The Prize Fighter Within –Your Action Plan

The signature movement of the serratus anterior is a good uppercut: the big swing of the arm as it wraps up and across the body is the reason it’s sometimes called the “boxer’s muscle” (yo, Adrian).But really, it’s in play whenever and wherever the upper body is dealing with force, whether holding a handstand, swimming the butterfly, passing a football, or doing a pushup. Serratus strength and coordination is thus foundational to just about any upper body movementRelative balance of serratus anterior and upper trapezius muscle activity during different exercises. Ludewig, PM., Hoff, MS., Osowski, EE., et al. American Journal of Sports Medicine 2004 Mar;32(2)484-93.. Many common exercises like shoulder presses can engage and strengthen the serratus (or not, if done without proper form) through the often-subtle shrugging, swinging, winging, or sliding of the shoulder bladeSerratus anterior muscle activity during selected rehabilitation exercises. Decker, MJ., Hintermeister, RA., Faber, KJ., et al. American Journal of Sports Medicine 1999 Nov-Dec;27(6):784-91.. Looking to develop some rib-gills? Here are a few exercises that isolate the serratus. Keep in mind the serratus’ full range of motion isn’t large, so small movements are the name of the game:

  • Serratus pushup — No equipment necessary (besides a floor).
  • Foam roller exercise — An upside-down version of the serratus pushup that uses a foam roller and light weights.
  • Serratus shrug — Like a dip with straight arms; for individuals with good upper body strength.