This is thoroughly answered here. Herein, what is the antagonist of elbow flexion?
The triceps is the antagonist because it is on the opposite side of the elbow joint and has the potential to oppose the elbow flexion. Now, if we are talking about active elbow extension, the triceps is the agonist because it causes the action, and the biceps is the antagonist.
One may also ask, what is the fixator in elbow flexion? A fixator is a stabilizer that acts to eliminate the unwanted movement of an agonist's, or prime mover's, origin. This would, of course, make everyday movements quite impossible. For instance, consider elbow flexion by the biceps brachii. When you do a curl, the biceps acts to flex the elbow.
Just so, what is the prime mover of elbow flexion?
The brachialis (brachialis anticus) is a muscle in the upper arm that flexes the elbow joint. It lies deeper than the biceps brachii, and makes up part of the floor of the region known as the cubital fossa. The brachialis is the prime mover of elbow flexion.
Which muscles act as synergists to the biceps Brachii in flexion of the elbow?
The biceps brachii flexes the lower arm. The brachioradialis, in the forearm, and brachialis, located deep to the biceps in the upper arm, are both synergists that aid in this motion.
