Tip: Master the Chin-Up Shrug

Most people perform chin-ups without first getting into a stable shoulder position. This can reduce the efficiency of the exercise. You need to create a stable base, which requires a conscious muscle contraction.

Take an overhand or parallel grip on a chin-up bar.
From there, lean back, raise your chest using the thoracic spine as a fulcrum, and pull the shoulder blades down and back.

It helps to try to "break" the bar apart. This exercise also works tremendously well to correct trouble with arching during the bench press.