The Circle of Durability.

The article below for some reason inspired today's soft rant. I hope you feel this is worth your time. 
Yesterday I talked about arch height and ankle mortise dorsiflexion and how we can obtain more global dorsiflexion range through some pronation, loosely meaning, some arch compression/drop and splaying apart of the tripod legs of the foot. Global arch flexibility is a piece of that puzzle.  This action of arch compression/drop/tripod splay moves the tibia forward in the sagittal plane and this is global dorsiflexion. Let me be clear however, a reduced ankle mortise dorsiflexion range of sagittal motion which is met by more arch height reduction/prontation/tripod splay, is still dorsiflexion however it is less sagittal dorsiflexion and a little more adduction and medial drift. This can bring the knee into the medial plane and it does promote more internal spin of the limb, this can be a problem.  None the less, it is still global dorsiflexion. It is something we see at the bottom of a squat, we see it because to get there most of us do not have all that dorsiflexion at the mortise. It is not abnormal, the question is, "is it safe for you? Can you do it repeatedly, safely?" It is where we go when we need more sagittal motion, but it may not be ideal, and is often what creates functional pathology. We see it all the time, someone says in an email, "I have plenty of ankle dorsiflexion, that is not my issue".  Do you have plenty? Is it not really your problem? This is fine tuning stuff, it takes a skillful eye and assessment hand. It takes experience to see the whole picture. You cannot get this full 4k experience and understanding from a 2 dimensional youtube video. This arch compression and pronation is normal to occur, it should occur, it must occur. But, how much is too much, for you ? I like to explain it this way, 

"there is a point at which sound, economical, durable, biomechanics becomes a liability. And, at that point where the liabilities begin is in fact where we begin to skirt the edges of that durable skilled movement. Where we begin juggling our liabilities is where the risks begin to mount and begin to whittle away or trump our S.E.S.P (skill, endurance, strength, power). This is where injury often occurs, at that intersection where the gas tank of our S.E.S.P. begins to run low and our liabilities begin to run high." 

I have explained this concept many times before when talking about the cross over gait. Moving towards a narrower step width is fine if you have the durability to be there. The question is, how long are you going to be there ? A cross over gait tendency is more economical but you begin to risk liabilities toward injury if that durability becomes challenged. As a runner you must know where your safe zone exists and know how much durability you have at those fringes of your movement. It is when you are there too long, too often, or too much that you empty that durability gas tank which then increases your liabilities towards injury. This is why I give high volume and strength work once a problem is solved, to make sure that they can keep that circle of durability high. It is when we stop keeping our gas tanks large and full that we run on fumes and our risks increase. You might be able to run economically for 5 miles with a narrow step width cross over style running gait. But, can you do it safely at 10 miles ? How about 15?  Is it any wonder why people get injured as they fatigue their safe motor patterns ?  If they have worked hard to keep that circle of durability large (S.E.S.P.) they are bound to be safer and less injured. Injuries occur because we exit our circle of durability, its gas tank has run too low, liabilities now trump economy and durability.

- Dr. Shawn Allen, the gait guys