The brachioradialis brachialis and biceps brachii muscles combine to the forearm

flex

The brachioradialis brachialis and biceps brachii muscles are the main flexor of the forearm. The brachioradialis is a stronger elbow flexor when the forearm is in a midposition at the radioulnar joint while biceps muscles is strongest from 80-100 degrees position. Moreover, these two muscles coordinate during elbow flexion movements with respect to hand position.    

Ais the answer hope this