Global body compensations in ACL deficient knees.

ALERT: Ok, this is big.
It is a huge comment on what the brain and reflexive patterns impart on posture and gait when perceived functional instability is present.
This study aimed to investigate the gait modification strategies of trunk over right stance phase in patients with right anterior cruciate ligament deficiency.
* Here is what you need to ABSOLUTLY keep in mind when you read it. The 3D capture it telling you what they are DOING to strategize, not what is WRONG or what needs CORRECTING (our mantra it seems, sorry to keep beating this concept to death). This again hits home what I have been preaching for quite some time, that arm swing (and you can translate that to trunk movements, thorax, head posture, breathing etc) should not be coached or corrected unless you are absolutely sure there are clean symmetrical lower limb biomechanics (yes, you can easily and correctly argue that you can concurrently work on all parts). IF there is something going awry in a lower limb, compensations will occur above, they have to occur. So be absolutely sure you are not making therapeutic interventions above without making therapeutic corrections below. If you are working on a shoulder/upper quarter problem and are not looking for drivers in the lower limbs or in gait, well … . . good luck making lasting effects. Other than breathing, it can be argued well that gait locomotion is our 2nd most engaged motor pattern that we have driven to subconscious levels , and compensations are abound (but not without a cost), so we can dual++ task.
If you want to dive deeper into this, search our blog and look for my articles on Anti-phasic gait. This is essentially what this study was looking at, and confirming, that there is a distortion in the NORMAL opposite phase movements (anti-phasic) of the “shoulder girdle” and “pelvic girdle” when something goes wrong in a lower limb.
– Dr. Allen

Findings from Shi et al when there was a chronic right ACL deficiency:
-trunk rotation with right shoulder trailing over the right stance phase was lower in all five motion patterns
– trunk posterior lean was higher from descending stairs to walking when the knee sagittal plane moment ended
– trunk lateral flexion to the left was higher when ascending stairs at the start of right knee coronal plane moment when descending stairs at the maximal knee coronal plane moment and when descending stairs at the end of the knee coronal plane moment
– trunk rotation with right shoulder forward was higher at the minimal knee transverse plane moment and when the knee transverse plane moment ended
– during walking, trunk rotation with right shoulder trailing was lower at other knee moments during other walking patterns

http://www.ncbi.nlm.nih.gov/pubmed/27131179

Muscle Activation Concerns

We are concerned about some things that are showing up in our clinics lately. Strange injury patterns we have not seen before. We know you are all very busy, because you are the best what you do, but we hope that by sharing these 2 articles with you we can all further raise this team of practitioners, coaches, physical therapists, trainers, pilates and yoga instructors, surgeons etc and work even more effectively as a team.  
This issue is about muscle activation or facilitation.
As you are all learning, this game is more than just turning muscles on, and there are risks to turning something on when the central nervous system has decided it is not safe to turn something on. We are all treating people who are slouched over all day either as students or at desk jobs and thus everyone (seeing as they are all dropped into hip, knee and cervical, thoracic and lumbar spine flexion) will have some degree of inhibited glutes (and thus reciprocal neuro-protective hip flexor tightness) that appear to need activated when the truth is that they need more central extension facillitation. Activating the glutes when there is a central flexion inhibition driver overrides the nervous system’s protective inhibition response. Hence the near-epidemic of hamstring and hip flexor/groin/labrum tear problems we are seeing !   There are logical reasons why something is not activated. Sometimes it is a 
1. muscle skill pattern (large diameter nerve, all muscle fiber diameters), 
2. sometimes it is an endurance problem (large diameter nerve, small muscle fiber diameter),
3.  sometimes it is a strength problem (largest diameter nerve, largest diameter muscle fibers). 
Knowing a problem is driven by 2 or 3 will tell the practitioner that activation will not solve the problem and that activation can force a compensation pattern that can lead to a future injury. Also, sometimes it has nothing to do with the muscles motor nerve activity, it may in fact be about the reciprocal inhibitory neurosensory input (see our post on reciprocal inhibition here). 
Hence we wanted to share 2 articles we wrote. These articles were spurred by the magnified influx in the last year of injuries that appear compensatory, meaning they seem to have occurred because alternative compensatory motor patterns were encouraged where there appear to be clear signs that they should not have been encouraged.  In other words, sorry to say this, people with a weaker understanding of how and why the nervous system works are using muscular activation as a tool when it is the wrong tool. When you are pounding a nail, using a screwdriver won’t get you good results, and might get you the wrong results. But, if all you have is a screwdriver … . .
The blog posts are below. We strongly believe that many of these injuries we are seeing are not necessary. We always ask ourselves when a person who we have been working on says to us “honest doc, I really did not do anything, I was just running comfortably and the hamstring grabbed at me for no apparent reason.”  These stories always make us look in wards and ask “is this injury my fault ?” “Did this occur because I was activating the wrong muscles and wrong patterns thus forcing them into a less worth protective pattern because I thought I knew better than their nervous system did ?” When we want to learn we judge ourselves and our actions  harshly, for we know we make mistakes and we know we are still students. We know that if it appears simple, it might be a good time to step back and think it through a little more. 
Don’t just be an muscle “activator”, be a thinker who occasionally activates when it is appropriate.  The nervous system knows better than you do, accept this and try to figure out why it is shutting things down.
Shawn and Ivo

image from : http://www.emeraldinsight.com/books.htm?chapterid=1775219&show=html