Because of the bicep’s small size (relative to other muscles we tend to work out), it is simple to isolate. Additionally, one can only lift (with the biceps being the prime mover) in one direction (up). The movement will most often be a variation of the curl. The motion begins with the contraction of the biceps. When training the biceps, there should be no shoulder involvement. Contract the muscle as hard as possible, for the entire concentric motion. The eccentric portion of the movement is also strictly regulated by the biceps, slowly stretching the muscle back to the starting position. The shoulder will act as a stabilizer, as will the forearm during the lift. Let your arms hang by your side. When you contract only the biceps, the lower portion of the arm comes up in line with your upper arm. The upper arm can move forward or backwards, depending on your body. However, it is easy to distribute the resistance to the deltoid and/or the forearm, rather than completely isolating the biceps. To alleviate this, move your arm so that tension is relieved from the forearm and shoulder, and kept on the biceps. Do this by beginning the movement with a biceps contraction, and relaxing your deltoid and forearm (this will loosen your grip on the weight). Focus on contracting the biceps up from where it meets the elbow to where it meets the shoulder. The “ball” of the biceps moves upward, away from the elbow, gradually shortening the muscle until it peaks and can not contract further. Biceps training is simply contracting the biceps against a resistance, with no help from the shoulder or forearms.