Let's take another look at how some classic dance cues can drive a lack of coordination within the shoulder girdle!
Your scapula (shoulder blade) is the base of support for your humerus - or arm bone. This means that when the humerus moves, the scapula moves with it and provides a surface on which the humerus can rest so that it can stay stable and/or bare load. Normally, when you move your arm overhead, your scapula should upwardly rotate 1 degree for every 2 degrees your humerus moves in order to keep the glenohumeral joint stable and relatively centered in the socket. Lack of scapular motion may drive excess movement at other joints, pinching of soft tissues under bone and popping and clicking among other issues. (Read more here.)
How common dance corrections can drive scapular dyskinesia.
In classical forms of dance, namely ballet, we are often given a host of corrections that, when built up over time, can drive scapular dyskinesia or atypical movement of the shoulder blade. For example, we are often told: bring your shoulders away from your ears to create a long line from the neck down to the finger tips. Downwardly sloping shoulders may be aesthetically pleasing, but there are some biomechanical consequences to living in this position. When we bring our shoulders away from our ear, we often use muscles like our lattisimus dorsi and our rhomboids. These muscles are absolutely necessary for certain movements, but when they are constantly 'on' or firing to try to keep our shoulders away from our ears, they can also inhibit the scapula from upwardly rotating and moving in tandem with the humerus.
A few years ago, I had a dancer approach me after class to tell me she was concerned because whenever she performed por de bras, her shoulder, namely her glenohumeral joint, cracked, popped and clunked. I observed her standing posture and noticed that her clavicles, which should gently slope upwards in anatomical neutral, were parallel to the ground and that her shoulders sloped down away from her ears. I then asked her to move her arms from fifth position en bas to fifth high. When she performed her port de bras, you could see her humeral head ride superiorly and then drop inferiorly into the glenoid as her arms traveled from second position to fifth en eau. This movement of her glenohumeral joint coincided with the clunk she felt during por de bras.
I took a look at her scapula from the back and noticed that when her arms were a la seconde, her scapula had not moved at all from their resting position even though her arms were to the side. Additionally, when her arms were overhead, her scapula were not completely upwardly rotated thereby not effectively creating a stable base for her humerus. Before helping her with her scapular positioning, I did a quick lat-length test to make sure the length of her lattisimus dorsi was not contributing to her scapular dyskinesia. Her lat-length was fine which made me think she might just be over-recruiting the muscles that downwardly rotated her scapula and depressed her shoulder and/or that we needed to address the neuromotor control of her shoulder girdle.
Together, this dancer and I went over a few cues to un-do some of the dance corrections her body had internalized. Within a few minutes, her scapula were upwardly rotating when she moved her arms from en bas to overhead. As soon as she was able to control the movement of her scapula and coordinate it with the movement of her humerus, her clicking and popping went away.
(It should be noted that at this particular time, I was acting as a conditioning coach and not a physical therapist, so I did not perform any manual assessment of this dancer. There could have been other contributing factors to her scapular dyskinesia.)
Food for Thought...
I wonder if we should reconsider the correction to keep the shoulders away from the ears. Maybe we should aid our dancers by clarifying that when we give that cue, we mean that we don't want the shoulders excessively elevated. Maybe we could help the dancer find the correct position of the shoulder instead of just saying 'down!'
Most importantly, perhaps we should consider why we need to continually give the correction 'shoulders down!' in the first place. For example, maybe the dancer's shoulders keep elevating because he or she is having trouble connecting to and effectively utilizing the core.
(Note: There are many things that drive scapular dyskinesia. This is just one simplified example.)
To read more about the scapula and scapular movements, click HERE.