Internal Rotation - Machine

Select the amount of weight you want to lift. With your left hand holding the handle, stand with the cable on your left and your left elbow next to your waist. Knuckles should be facing away from you.

Rotate your upper arm towards your body as you lift the weight as far as you can without moving your elbow, then lower slowly back to the starting position. Repeat with other arm.

Shoulders 

Subscapularis

TIP: Think of pivoting from your elbow so that your upper arm is always parallel to your body and perpendicular to the floor.