To get a feel for shoulder girdle movement.
round your shoulders to Protract your shoulder girdle (avoid this position
when standing, sitting and especially when doing most exercises). OK, relax
your shoulders. Now
shrug your shoulders to Elevate your shoulder girdle. Avoid shrugging
when doing curls, lat pulls, lateral raises, and any movement where your
target is not your upper trapezius. Relax your shoulders.
Pinch your shoulder blades together to Retract your shoulder girdle
(hold this position); and
pull your shoulders down as far as possible to Depress your shoulder
girdle. These last two movements are one of the components of good posture,
and are often described in your Sport Fit Cards as lifting your chest, or
keeping your chest high.
By assuming this retracted / depressed shoulder girdle position you are
able to stabilize your shoulder girdle so that you can effectively isolate
and train muscles that act on your shoulder joint--you chest, your lats,
and your delts. Remember, precise training is what brings about the greatest
physical improvements for your time and efforts.