As with the reverse barbell curl, the use of the pronated (overhand) grip during the EZ bar curl results in brachioradialis and brachialis stimulation, whilst activity of the biceps is muted.
The brachioradialis is a muscle which runs from the forearm to the upper arm, and is responsible for the flexion of the arm. This is why the reverse curl is often cited as a good forearm exercise, with the brachioradialis composing a large chunk of the anterior forearm.
The brachialis runs beneath the biceps, and like its more popular neighbour, is also an arm flexor. Its activity increases with a neutral (palms facing inward) or pronated (palms facing down) grip, as the role the biceps play lessens.
The use of the arm flexors are seen in an array of sports, prominently within sports which involve contact with an opponent. The reverse EZ bar curl could prove a useful tool for developing such arm flexor strength.