The brachioradialis is located to the upper outer region of the forearm. It originates from the humerus (bone of the upper arm) and is therefore responsible for the flexion of the arm.
The muscle is particularly active when a neutral (palms facing inward) or pronated (palms facing down) grip is used during arm curls. Thus, the brachioradialis can be targeted with exercises such as overhand barbell curls, hammer curls, rope curls and Zottman curls.
Many back exercises, such as the bent over row, dumbbell row and pull up, will also recruit the brachioradialis effectively as they involve the flexion of the arm whilst using a pronated or neutral grip.