A close-packed position is the maximum contact area between a joint’s surfaces.
With the shoulder, this position is achieved at 90 degrees of shoulder abduction and full external rotation – like the shoulder in a pull-up position.
Structural Implications
In this position, much of the ligaments and tissues surrounding the joint are under tension. So, compressive and shear forces are increased when exercising in this range of motion. With this comes an increased risk of injury with behind the head exercises such as behind-the-neck pulldowns or presses.
Better options for shoulder health are front lat pulldowns or front shoulder presses.