The rhomboids and the middle trapezius retract the scapula.

Complete scapula retraction (pinching your shoulder blades together) is practically impossible to during a heavy deadlift. The rhomboids and the mid-traps will never be strong enough to maintain the position. Besides, it is unnatural to have your shoulders retracted when a heavy weight is hanging off of your hands. It’s like trying to deadlift with your wrists curled (false grip).

Keeping your scapulae retracted artificially and forcefully is not a natural position for your shoulders. One of the best ways to cause shoulder impingement is to keep your shoulder blades back during pulling exercises all the time. You have to let the shoulders roll or respectively elevate at the bottom of each repetition in order to avoid impingement. Retraction during back exercises like pull-ups and rows is required but not throughout the whole movement. At the bottom, the scapulae should be allowed to protract naturally.

Another side effect of artificial scapula retraction during deadlifts is the increased range of motion. Retracted shoulders technically shorten the arms and consequently make the pull harder.

Therefore, you are not only risking tears and impingement, but the weight you lift is limited too. You will never see a heavy deadlift done with retracted scapulae.

One of the main reasons why people wrongfully recommend scapular retraction during deadlifts is that it allegedly promotes a good back position. However, that’s not really the case. You can retract your scapulae, even when your back is rounded to extreme degrees. This coaching cue is ineffective for maintaining a proper spinal alignment during deadlifts. You can try it for yourself – assume a “Quasimodo posture” and pull the shoulders back. It’s possible.

The most important cue for maintaining a good posture is to push your chest out. For most people, this will arch the whole back at the right places.

Place your hand 10 inches in front of your chest and try to reach it with your sternum. That’s what “pushing your chest out” really means. You will feel your posture improve right away.

To summarize:

– scapular retraction during deadlifts is potentially dangerous and limits the weight that you can lift

– keeping your shoulders retracted the whole time during rows and pull-ups can cause shoulder impingement

– try to actively push your chest out during deadlifts in order to maintain a proper back alignment