It's a term that gets thrown around a lot on the internet—including here on STACK.com—but do you actually know what it means? While you may have some idea, learning the definition and function of stabilizer muscles can make you a more knowledgeable gym-goer and help you get the most out of your workouts.
What are Stabilizer Muscles?
Stabilizer muscles work to stabilize the body and its extremities during multi-plane movement. During an exercise, there are primary movers and stabilizer muscles. The primary movers are the muscles doing the majority of the work—they're what's moving the load and they're likely where you'll feel the exercise the most. While the stabilizer muscles aren't directly involved with moving the load, they work to keep certain parts of the body stable and steady so the primary movers can do their jobs efficiently.
While no one muscle is a stabilizer muscle 100 percent of the time (since it's more of a role than a persistent state), certain muscles work as stabilizer muscles much more frequently than others. The rear deltoids, for example, are rarely the primary mover in an exercise but frequently act as a stabilizer during movements that involve the shoulders.
"The rear delts act as a main stabilizer when your elbows come parallel to or behind your body," explains Rick Scarpulla, strength coach and owner of Ultimate Advantage Training.
For example, though the primary movers of the Bench Press are the pectoralis major and the triceps brachii, the rear delts act as a stabilizer muscle to help you control and decelerate the bar effectively. Stabilizer muscles can serve several different roles, but they often work to re