Arm Training Tip: To optimally develop the elbow flexors (the brachialis, biceps brachii, and the brachioradialis) you have to vary hand position and the position of the elbows in relation to the torso.
When the elbows are in front of the torso, with a supinated or semi-supinated grip, the short head of the biceps brachii is heavily recruited. When the elbows are in front of the torso with a pronated, semi-pronated, or neutral grip the brachioradialis (to a degree) is preferentially recruited. When the elbows are in line with the torso the brachialis is targeted and when the elbows are behind the torso the long head of the biceps is emphasized.
Varying hand positions – supinated, semi-supinated, supinating, pronated, semi-pronated, offset, neutral, etc. – on a number of elbow flexion exercises is a great way to further develop the elbow flexors.
Using thick barbells, dumbbells, and other implements is much better for continued strength development when used in conjunction with standard diameter equipment.
While thick handled dumbbells and barbells are not exactly commonplace in most commerical gyms this problem can easily be solved by investing in a set, or multiple sets, of Fat Gripz.