Regional interdependence is a concept that I explain on a daily basis but I hardly ever call it that unless I’m speaking with another physical therapist or a really good strength and conditioning pro. Clients come to our clinic to get our take on why they hurt and “what might be causing their pain”. After all of our questioning, measuring, observing and differential diagnosis (complicated way to say: guess as to what the problem is and then test your theory to land on the most likely answer) we come to the “functional diagnosis“.
This is usually in language that most who seek our help have heard before. It sounds like, “You have a Grade I strain of your right hip adductor muscles, specifically, your adductor magnus”, or something like that. Maybe the person came in to us with a “piriformis syndrome” or “hernitated disc” diagnosis from their specialist. Even better, maybe Google told them that they have “osteoarthritis”, and that there is no cure and nothing you can do about it.
Whatever the final answer is, it’s rare that there isn’t an explanation for “WHY” any of this pain or restricted movement came about, and this is where “regional interdependence” was born. It’s the complicated way (we physios love our complicated terms) of saying the ‘knee bone is connected to the neck bone’.
Here I want to outline a simple to understand concept called Movement Economics, that:
- makes understanding and explaining regional interdependence easier,
- serves as a platform to understanding about how strength and conditioning and injury prevention/rehabilitation go hand in hand, and
- how physical therapists and strength and conditioning pros can work together to enhance the movement and performance of their clients, that is, when they aren’t the same person.
Movement Econ 101: The Basics
- All movement has a cost; we use ‘movement funds’ to pay for any and all coordinated and purposeful movement.
- We each have a ‘movement account’ which allows us to move with varying intensity and volume.
- To increase the size, make deposits into your ‘movement account’, thereby increasing your work capacity, you can increase your strength, coordination, skill level, mobility, endurance… the list goes on.
- Those with low ‘movement account’ balances are typically weaker, less mobile, less agile, less coordinated, less skilled, etc.
- If you attempt a movement that comes at too high a ‘cost’ then you are at risk of ‘overdrawing your movement account’. This is an acute injury or pain state.
- Movements that are done too repetitively can have the same impact. Even if a movement has a ‘low cost’, there is no such thing as an infinite ‘movement account’, and you become at risk when a less ‘expensive’ movement is done too much.
To best understand this concept we need to take a very specific movement into consideration. The movement we are talking about here will be a low level, easy to perform movement. As you will see, even the most simple movements require many steps and systems working properly in order for the movement to happen without any ‘issues’. If there is a Movement Econ issue, we will see system corrections and compensation that will make simple movements more complex, thereby increasing their movement cost and eventually, overdraw the movement account.
The movement under examination here is: ascending one 7″ ADA compliant stair with your left foot. Here I will provide a brief case study and the regional interdependence/Movement Econ explanation for why this clients’ pain began from a small change that decreased her ability to ascend the stairs and now she presents to our clinic with left-sided back and hip pain diagnosed by a physician as “lumbago” (smh).
For the purposes of this example we will lay down some assumptions and build the case. These are only estimates of real requirements for our mobility example. While the exact figures may vary person to person by a small margin, the point will remain the same. Climbing one 7″ ADA compliant stair with your left foot REQUIRES:
- 15 degrees of active left ankle dorsiflexion
- 90 degrees of left knee flexion
- 80 degrees of active left hip flexion
- near full strength of the right hip abductor muscles
- near full strength of right sided trunk muscles
- near full strength of the left hip extensor muscles
- near full strength and mobility of the spine for extension
- at least 0 degrees of available hip extension of the right hip
While this might look like a long list of requirements for something as simple as climbing one stair with one foot it’s actually far from complete. For the case we are examining here it’s more than enough to paint the picture.
Our client presents to us with pain (an overdrawn movement account) in her left sided low back with some mild radiation to her sacroiliac area and a bit lower into what she senses as her ‘sits bone’ on the left near her glute max. If we only heard this complaint and evaluated her, we probably would come to the same conclusion as if we took the “Movement Econ” mindset. Her paraspinal muscle strain, likely her left quadratus lumborum (QL) would be found with a couple movement based tests and some easy palpation. We’d teach her what she needed to know about muscle tissue healing. We’d likely supervise her and prescribe some trunk muscle mobility and strengthening work so that her QL was better capable when it healed. Slam dunk!
Now, what if we mentioned that upon FULL examination it was discovered that she only had 3 degrees of active dorsiflexion of her left ankle? Does this change how you will treat her QL strain or how long it will take for her back and hip pain to resolve?? Probably not. What it does change, however, is whether or not you will see her AGAIN in your clinic for the exact same thing. Here is where an intimate understanding of Movement Economy comes in very handy.
Our client cannot actively dorsiflex her left ankle given the effort of the surrounding muscles and accessibility of the joint to do the movement we are examining (decreased movement economy=increased movement costs). In order to clear her foot to the next step she must increase the amount of work that she does to flex her left hip (spend more movement funds), let’s say to 95 degrees. It is only a matter of time, or volume in this case, that her left hip flexor muscles will become fatigued (increased movement costs=closer to overdrawing the movement account). After all, those muscles already have their own task to perform (normal movement costs). The extra work load, while not a lot by itself (‘low relative movement cost’) is added to the work that has to be done making the movement overall less efficient and ‘more costly’.
The left hip flexor muscles take on the new movement cost and we continue climbing stairs. Now the hip flexor muscles are near failure (overdrawing the movement account). This might be cumulative over many stairs during the course of a week or month, but the scenario is the same; we are further into movement account debt!
How can we clear that foot to the next step if we are missing ankle dorsiflexion AND hip flexion? One way would be to left side bend! Of course, this is done in closed chain on the right leg and so here is where the QL got involved. If one were to examine this movement we would find that the QLs would “normally” work in conjunction with the right hip abductor muscles to stabilize the trunk and keep us moving mostly forward without too much unnecessary side bending. In this scenario, the left QL has it’s role (normal movement cost) AND an additional role of clearing the hip for the fatigued hip flexors (increased movement cost) which are fatigued because we don’t have enough left ankle dorsiflexion!
And that’s it! We examined the client fully understanding the Movement Econ picture that was in front of us. We found areas of poor movement economy. Addressed the acute pain/restriction, as well as the likely reason this all started and now we will not have the dubious pleasure of treating her again for the same complaint.
This was an example based on a true patient case. The pain and restriction was the result of a low level movement econ issue combined with a high volume. Now envision the case of the 17 year old elite level, highly competitive baseball pitcher that we examined and treated in the very next hour who came to us with dominant shoulder pain. Elite level throwing is one of the most violent single sports movements we know (VERY HIGH movement cost). Where do you think we started our search for answers and where do you think we ended up? If Movement Economics is the foundation that guides some of your clinical decision making, then you are already on the right track to having the pleasure of seeing this client more often on the baseball diamond than you see him in your clinic; just how we like it.
Dr. Carlos J Berio, PT, DPT, MS, CSCS, CMTPT is a licensed Doctor of Physical Therapy, Certified Strength and Conditioning Specialist and a Certified Myofascial Trigger Point Therapist. In addition he holds a Master’s Degree in Clinical Exercise Physiology. He has treated high school, collegiate, recreational, and professional athletes of various sports including baseball, softball, football, hockey, tennis, swimming, golf and the martial arts. His experience as a collegiate and semi-professional athlete as well as a professional baseball coach make him a sought after resource among elite level athletes on the field and in the training room. The concept of ‘all the way well’ in his work as a physical therapist and fitness professional is what continues to drive Dr. Berio to be the best movement specialist there is.
Carlos remains active in several sports and is an avid agility training, power lifting and adventure race runner. He is an advocate for his patients, clients and his fellow PT colleagues. He can be reached at firstname.lastname@example.org.