Muscular Superheroes: Agonists, Antagonists, Synergists and Stabilizers

What are muscle agonists and antagonists? Watch the short video below and review them with a little help from Batman and Robin.

Muscular Superheroes: Agonists, Antagonists, Synergists and Stabilizers

Moving any of our synovial joints requires a community effort. While the “agonist” muscles are the prime movers of a joint, there are other muscles that kick in to help guide and stabilize that movement. You can think of the muscle community that comes together to move your joints as superheroes. For fun, we’ll use Batman and his cohorts as an example.

Here’s a quick review and summary of the relationships of muscles around a joint.

Batman: The Agonist
The main muscle trying to create a movement at a joint.

Joker: The Antagonist 
The main muscle that does the opposite action at the joint.

Robin: The Synergist
Muscles that help the agonist do the same movement.

Alfred: The Stabilizer
Muscles that keep everything else in place while the agonist and synergists are trying to do their work.
The relationship between the agonist and antagonist muscles is called “reciprocal inhibition.” As the agonist contracts to move a joint, the antagonist is automatically relaxed by a reflex arc in the spinal cord. That’s good because otherwise, it would fight against the movement like Joker would fight against Batman!

For example, in a yoga pose such as Paschimottanasana (Seated Forward Bend) (below), the quadriceps muscles are the agonists—because they contract—and the hamstrings are the antagonists—because they stretch. Similarly, when we bend our elbow, the biceps (agonist muscles) contract and the triceps (antagonist muscles) stretch to allow for the elbow to bend. (see illustration above)

How does this knowledge help us? Contracting an agonist at a joint generally helps us stretch the antagonist, so a little help from Batman and Robin can go a long way to help deepen your yoga poses and achieve a better understanding of them.