Comprehensive Capacity: an alternative to the kinesiopathological model for shoulder function
The gist: Ideal shoulder positioning, ideal muscle activation timing/coupling and corrections are unnecessary and unsupported when dealing with patients with shoulder pain.
Caveat of doubt: Scapular dyskinesis may not matter for most patients but we should always be open to biomechanics being relevant in some specific conditions
The point: Many therapists advocate an alternative to the kinesiopathological model of pain and injury and what we often hear is a touch of exasperation from other therapists. We are challenging the dominant view and it leads to the big question "Well, what the hell do you do then"? Its a good question and I'll shed some opinion flavoured with some evidence in this post. An old post that goes into some of these ideas and "functional' movement is here.
It has been proposed for more than 15 years that there is an ideal way for the scapula to move. Essentially, it provides a base of support for the humerus and if it is presumedly "unstable" then shoulder injuries might result. Even more simply, the scapula has to get "out of the way" of the arm bone by rotating upwards, rotating posteriorly and retracting. Related, it is proposed that proper muscle timing and activation ratios will need to these wonderful kinematics and the shoulder will be happy. In the therapy world it is common to hear that the Serratus Anterior is not firing properly or the upper traps have too much activity and this is leading to dysfunction. Good luck finding a reference that actually supports that commonly held clinical belief or one that shows that that timing changes with rehab and correlated with pain reduction.
My HUGE bias:
There is very little research supporting the idea that dyskinesis is related to future injuries or that changing kinematics relates to pain reduction. Now a few studies looking at those ideas:
Struyf 2014 showing scapular position/kinematics not related to future injuries in overhead athletes. Conversely, Clarsen (2014) showed that scapular dyskinesis was related to future injuries in handball players (albeit, the CI range was pretty large which should cause you to pause at this finding).
- Do those in pain move differently?
- Do those altered kinematics HAVE to change?
This to me is the most important question. It is reasonable for a therapist to look at the correlation data and see that sometimes people with shoulder pain move differently. A reasonable intervention would be to change their movement habits/behaviours. But this is different than saying we have to change how their shoulder moves to the presumed ideal shoulder movement.
Surprisingly, there are few studies that look at how kinematics change with rehab. Here are three that show that people get better with rehab yet there was either no change in kinematics (Carmargo 2016) or the rehab resulted in what many would consider poorer kinematics (e.g. decreased upward rotation, increased protraction seen in Struyf 2013 and McClure 2004) .
The above is obviously not a thorough literature review but it illustrates the notion that wonky scapular movements and timing is not dramatically related to shoulder pain. And I know that you this too. You all have those patients with a hugely winging scapula on the side that is not painful. You've treated those swimmers whose scapulae look like they are going for a swim. And this all makes sense. You want that scap to move. You want it to get into different positions and be able to tolerate loads. Think of rock climbers or dancers or even someone reaching their top cupboard for their hidden whiskey bottle at 2am. Raising the arm with shrugging or protraction or anterior tilt is totally normal.
Be a Movement Optimist!
The Alternative - Comprehensive Capacity
I'm happy to see that plenty of people are onboard with this theme now. I think we will see more and more of it. My favourite recent paper (because it confirms my bias :) ) is by McQuade et al 2016. These authors (definitely Dr Borstad) have a track record of supporting the scapular dyskinesis theme. But they have made a massive shift and completely question the model in this paper. And what do they propose instead? Essentially, that you ask the most out of every joint around the shoulder and the shoulder itself. Since we can't say what is ideal movement we suggest that the shoulder joint, the scapula, the thorax and everything connected by functioning as best they can. Ideal function in this case being that every joint is maximizes all of its Biomotor abilities (strength, endurance, ROM, power etc).
What does Comprehensive Capacity look like in practice?
It depends. My general approach can be seen here. Does every patient with shoulder pain need to train their entire system extensively? No, of course not. So, we have a few choices when it comes to shoulder pain. Here are some possibilities when confronted with a patient who has shoulder pain during arm elevation.
1. Desensitize the entire person. Look for everything that can contribute to pain and try to make all those areas healthier. Find the aggravating movement habits and teach them a few different ways to move. Reiterate that changing those movements is just temporary and that as things settle down they can go back to moving however they like. Perhaps give both shoulder and scapular exercises as part of the desensitizing scheme. These patients might not use their shoulder a lot and there is really nothing to build them back up to. They just want out of pain.
2. Symptom Modification, Desensitization and Resumption of Activities: Same as #1 but perhaps add more symptom modification procedures and build them up more to tolerate many meaningful activities. Find the thing that hurts and then change something about that. Symptom modification and movement behaviour change is now driven by symptoms and not by ideal positions. If your patient consistently raises their arm with their shoulder blade down and back and this hurts then perhaps you teach them other ways to do it. Then look at the activities that your patient wants to do and slowly build up their capacity to tolerate those activities. You are choosing exercises based on what the joint is potentially capable of and what might need to tolerate in the future rather than nitpicking about timing and position. You ask the joint 'What do you have to do?" and then you say "OK, lets do that". If you need more prescription or a system in these types of exercises then my colleagues at Functional Anatomy Seminars might help with their FRC approach. What is exciting about these movement changes is that they don't need to be done forever. You are changing the movement as a temporary reprieve and then the person can go back to moving that way without pain. This is consistent with the Cognitive Functional Therapy approach to low back pain. Most importantly, they keep doing the things that are important to them and the exercise prescription prepares them to tolerate those important activities.
3. Secondary Prevention: If someone has activities or sport that require a lot shoulder movements we prepare the whole system to tolerate all of those movements. This is essentially what most good injury prevention programs do and what most rehab programs do. Although, the clinician might say they are working on ideal shoulder movement or scapular stability what they are really doing is just training the whole system to be robust. Its a good example of Movement Preparation trumping Movement Quality. Look at this shoulder injury prevention program by Andersson et al (2016). It is comprehensive capacity. It is a program that addresses a number of factors.
No one is ignoring movement here. You can still change how people move but I would argue that you aren't changing movements to "ideal" movements rather pain free ones. At the same time, you do your regular rehabilitation to try to desensitize those movements as well. Concomitantly, if exercise is your means of therapy then you choose exercises not to correct movement patterns or change timing but to get the most out of every joint up to and exceeding the demands placed on the person. If someone has shoulder pain and they don't do much shoulder activities then working on handstand pushups isn't necessary. If you work with a rock climber then you better train the shoulder, spine and hips in a bunch of different positions. Your comprehensive capacity matches the demands placed on the person.
This post is pretty mechanical. Staying firmly in the Bio of the BPS for simplicity sake. You can also apply the Comprehensive Capacity idea to entire person. Meaning, we don't know what psychosocial contributors there are to someone's pain. You can't partition shoulder pain to 30% depression, 13% anxiety, 6.2% catastrophizing, a dollop of sense of injustice and a bushell of poor sleep. So we do the same thing with these factors. Essentially ask "How can you be healthier?" and then work on strategies to address all facets of someone's life.