In Vern's recent post on working with his volleyball players, he mentioned exercises designed to "emphasise shoulder lag & hip lead".
There's too much of this "keeping the humerus in the scapular plane" stuff going on. In certain shoulder conditions it may be helpful to start there, I understand. However, the shoulder capsule is not a passive structure. It is rich in proprioceptors- Pacinian Corpuscles, Golgi-Mazzoni Corpuscles, Ruffini Endings, Golgi Endings- to name a few. They communicate by way of fascia with the rest of the body.
Dave Tiberio of UConn coined the term "proximal acceleration" to describe the phenomenon that feeds these proprioceptors. That is, the proximal segment moving faster than the distal. This places a specific stress on the capsule that lets it know what it needs to tell the shoulder musculature. Which muscles to contract, when to contract, at what speed, in what sequence.
In my work with my dislocated shoulder athlete, I'm using this concept. And I can do it safely, provided I sequence it properly. The picture shows me with a 3lb. implement with wheels on it so it can roll on the wall. I begin with the implement in my left hand at shoulder height, feet shoulder width apart, L foot forward, R externally rotated. I am leaning onto my left foot. Then I take a R rotational step with my L foot to meet my R. My LUE is rolling straight up the wall. I quickly return to the starting position.
This exercise looks like it may be containdicated for this shoulder condition, but look closer. Although the shoulder is abducted, it is also internally rotated. In addition, stability is afforded to the shoulder in the sagittal & frontal planes by way of the wall. I can increase or decrease the athlete's threshold by controlling how far he moves the hand up the wall in relation to the quantity & amplitude of foot movement. Heck, I can even do my posterior GH glides as he's exercising. It's all in the sequencing.
I'm feeding the core, I feeding the capsule, I'm feeding the shoulder- I'm getting hip to shoulder.