Contracting the triceps allows the forearm to be extended with the elbow straight; when the triceps are relaxed, the forearm retracts and the elbow bends. The triceps, which is a major muscle in the upper arm, also helps support the shoulder joint which is relatively unstable, according to Healthline. The bottom of the triceps is also involved in retracting the elbow when the arm is extended.Continue Reading
The triceps brachii and biceps brachii, as these muscles are technically labeled, work together to move the forearm, according to Education Portal. Contraction of the biceps enables the arm to be flexed, while contraction of the triceps brings the arm back down.
The biceps is called the agonist because it is the primary provider of power, according to PT Direct. The triceps works against the action of the biceps, which is why it is called the antagonist. The two muscles work in concert. While the biceps is contracting, the triceps may relax to allow the movement to take place. In some situations, the antagonist retains some tension to slow or stop the movement. During certain motions, when the elbow extends against gravity such as during a push-up, the triceps becomes the agonist to protect the joint.Learn more about Medical Ranges & Levels