Start: To put more emphasis on the short (inside) head of your biceps, attach a straight bar to the high pulley, and set a bench beneath it. Grab the bar with an underhand grip, and lie on the bench with your head close to the weight stack. Hold the bar with straight arms over your chest.
Finish: Curl the bar toward your forehead, trying to keep your upper arms in their original position. Stop before the bar touches your head, pause, and allow it o rise until your arms are almost straight but not fully locked out.