Pain in Shoulder Mobility Screen

Question from D1 Volleyball S&C Coach. I believe they have won a national championship recently as well.My men's volleyball team is tearing up the FMS- average score is a 17.Most shoulder mobility is 2 or three (still with some differences between the two arms), however I have a lot of them testing positive for pain. What should I be looking at? Mobility is good but impingement continues to be an issue.In considering the Shoulder Mobility Screen in the FMS, it is impacted primarily by the gleno-humeral joint, scapula system, and the thoracic spine. Certainly you can go down the chain through the core, etc. as well as the neck which is a lot easier to see the contribution to shoulder pain.  The point is that the "shoulder" really encompasses quite a few joint systems beyond the gleno-humeral joint.So if we have good 2 and 3 scores, we can rule out a general mobility issue. That doesn't mean that every single athlete has great mobility in the GH joint and/or t-spine. They could still be poor, and mobility elsewhere is making up for the excursion.  In this case, that elsewhere is the scapula.So the likely culprit for the impingement pain is the scapula via a lack of stability.  Always keep in mind that the scapula has to move.  We know this.  But also remember the definition of stability that I use is "control of a joint system in the presence of potential change."  It doesn't mean locked down into depression and downward rotation. That has value in certain lifts like pressing as a relative position, but it is not the embodiment of true stability.  True stability is a control of motion.So in the population of elite volleyball, particularly D1 national champions, much like pitchers, these guys at some point were able to figure out that if they could cock their arm back farther, they could hit harder bombs. And through this motor learning process, letting the scapulae go a little bit in the name of more range led to success. In these cases, this motor "teaching" becomes motor learning with the cement of success. The CNS registers success from somebody eating the ball, not if the rotator cuff clips the coraco-acromial ligament. Young athletes recover so they may not register any pain in ingrained dominant patterns like spiking the ball. Reaching behind their back is novel and fresh, so the impingement regsiters as pain.Something related to consider though is that volleyball is probably not a sport that these athletes have played their whole life. For many of these athletes, they have ultimately been selected to excel in volleyball not by anthropometry, height, or power, but maybe rather their ability to control their body inefficiently, develop more mobility and whip in the hitting hand, and potentially hitting the ball harder. This ability may have selected them to move on to D1 vs. D3 or at some level select a different sport. My point is when you see an athlete that fails the Screen but still has mobility or registers FPs on the SFMA, this is a motor control issue, a stability issue. It's not as much a shoulder or volleyball problem because I bet they would be a sports hernia if they had success in hockey or soccer, a similar shoulder, elbow, or neck problem (think Randy Johnson, Kerry Wood, Marc Prior, Strassburg, the list goes on) if they were a baseball player, a back problem if they were a recreational powerlifter or girya.Also something to consider is Total ROM, which I believe Todd Ellenbecker coined back in the mid 90s. He found it then in tennis players and many others have studied this in baseball players to suggest that GIRD is basically a bony deformity rather than a thickened posterior capsule limiting posterior humeral glide and internal rotation. While I agree that GIRD is probably not the case in most baseball pitchers, in this case with the volleyballers, I think it is. I think it would far less likely that these volleyballers would have developed the repetitions of spikes as youths to affect the bony changes that can be seen second to the trillions of throws a baseball will have made since the age of 5 or 6 years old.The treatment for these guys would be to remodel soft tissue of the rotator cuff and posterior capsule, joint mobilization of the posterior capsule, and stability progressions. I tend to think pull-ups may be the pinnacle progression second to being suspended in the air similar to the cocked, contact, and follow-through position of the spike. Anti-extension training would also be paramount to limit the stable segments from contributing to the whip. You can get the juice the wrong way and wind up with shoulder pain, or you can get it the right way, maybe take a step back in pounding the ball in the short term, and be even more of a beast in the end.