Brachialis

The brachialis is a muscle that runs under the biceps brachii, and is responsible for elbow flexion- brachialis in Latin means 'to the arm'.

The brachialis has major involvement in elbow flexion regardless of the grip being used during the exercise.
The brachialis is important in some sports, where grabbing and pulling are readily used, along with other elbow flexor muscles. The brachialis and biceps brachii will also create important balance to the elbow joint for people who use the triceps brachii in overhead movements such as throwing and hitting in their disciplines.

Exercises that require flexing at the elbow will recruit the brachialis, and these exercises can be viewed in the exercise section to the right.

Brachialis will be stimulated by rowing and pull-up exercises that require elbow flexion during the movement. Some people opt not to directly isolate the elbow flexor muscles such as the brachialis with many isolation exercises, but instead rely on stimulation via compound movements that require the elbow to flex. The Pull day on a three day Push, Pull, Leg split will recruit the brachialis effectively, just via the rowing and pull-up compound variations, and maybe one elbow flexor isolation exercise to finish off, such as biceps curls.

For those wishing to isolate the brachialis and biceps brachii, effective exercises can be viewed to the right. These flexor muscles are very important to bodybuilders, as the biceps brachii (and therefore other elbow flexor muscles) are probably one of the most flexed muscles on stage.
For hypertrophy 6-12 reps will likely yield the best results, providing optimal time under tension, adequate stimulation for sarcoplasmic hypertrophy, and acute response to anabolic hormone concentrations, compared to that of lower rep ranges.
If however strength and power is the primary goal then the brachialis and the biceps brachii will likely be best stimulated via rowing and pull-up movements, where 1-5 reps can be incorporated more successfully. Lower reps don’t always suit isolation movements, as form may suffer, and increase chances of injury where excess load is often placed on one or two joints.