Chicken or the Egg
DOES STABILITY PRECEDE MOBILITY OR DOES MOBILITY PRECEDE STABILITY?
There are various schools of thought concerning this question. Some believe that in order for one to exhibit mobility, proximal stability must take place to provide a foundation to support said movement. Some believe that without mobility there is nothing to stabilize. Thus, mobility must come before stability. Then there are others that reside within the various shades of grey of these two ideas.
While neither of these ideas trump the other and neither of these ideas are incorrect, I will propose a slightly different way of approaching this dilemma. Let us explore these ideas in an attempt to gain understanding.
While the concepts of stability and mobility have been around for some time, two prominent figures have been assigned as leaders of each: Shirley Sahrmann and Gray Cook. Sahrmann believes that stability needs precede mobility. Cook believes that mobility needs precede stability. The goal of this article is not to explore the differences of these approaches in an attempt to elevate one over the other, but to explore a common ground of which these two approaches can potentially become one.
A case for stability before mobility
It is much easier to shoot a cannon from a battleship than it is from a canoe. The battleship offers a stable platform from which the cannon can be mobilized/operated with success. The canoe offers little stability and therefore complicates the successful operation of the cannon. The body does not differ in this respect. It is widely accepted that proximal stability gives way to distal mobility. Nothing illustrates this better than watching a baby go through the process of developmental kinesiology.
The ability of a 3+ month old baby to lay on its back and lift its arms and legs in the air (see pic) is rooted in proper axial skeleton (spinal) stabilization. The baby must first secure an adequate base of support to enable limb movement/mobility. Foundational stabilization must occur to enable efficient functional/active movement. This is the case whether you are rolling over in bed, moving from sit to stand out of a chair, reaching for an object overhead, ambulating up/down stairs, picking objects up from the floor, kicking/hitting a ball, etc, etc.
Unfortunately, one's foundational stabilization does not have to be ideal to "complete" the above noted tasks, but execution will not be optimal. The danger in this is that it allows one to perform given tasks in a dysfunctional manner thereby increasing his/her's chances of breakdown/injury without warning. This is much like a car that is in need of a front-end alignment. The driver happens to lack the ability to perceive this mal-alignment, or ignores it, as it doesn't prevent him/her from driving the vehicle. Over time this faulty alignment/stabilization gives way to premature asymmetrical tire and associated wheel wear, resulting in excessive car maintenance costs.
Let us provide an operational definition of "foundational stability". For our purpose, foundation can be defined as "the base on which something stands" or functions. Stability can be defined as "the ability of an object to maintain equilibrium or resume its original upright position after displacement". Together they give birth to the ability of the base upon which something stands/functions to maintain equilibrium and/or to resume its original position after displacement.
Stability is not just the lack of mobility as often this is accomplished via rigid co-contractions. While rigidity is certainly a component of stability, it is not synonymous with stability. Stability is the intricate balance between the yielding and non-yielding. In the human body, stability is largely regulated via motor control/coordination/timing.
Given this perspective on stability, it is not difficult to see why one would support the case of stability preceding mobility. After all, how efficient and effective can one's movement be in the absence of foundational stability?
A case for mobility before stability
The argument for mobility preceding stability is simple. If stability is the ability of an object to maintain equilibrium or resume its original upright position after displacement, then what is there to maintain or restore if the object/segment lacks mobility in the first place. The simple question is, what are we stabilizing? We are stabilizing unwanted mobility.
For instance, take the individual that has fractured their arm in a manner that requires a full arm cast. The continuity of the bone has been disrupted in a way that has introduced mobility in an area and manner that inhibits the bone from being able to do its job. As a result, external stabilization (the cast) is applied to prevent the unwanted mobility while the bone heals to a point where internal stabilization (a stable calloused/healed fracture site) can secure and thus eliminate that disruptive mobility.
Earlier we discussed the idea that the ability for a 3+ month old baby to lay on its back and lift its arms and legs in the air is rooted in proper axial skeleton (spinal) stabilization. What is it that the baby is stabilizing within the axial skeleton in the first place? That's right, the mobility that occurs between the vertebral segments. But what is our operational definition of mobility? Mobility can be defined as "the ability to move in one's environment with ease and without restriction" or "the ability to move or be moved easily and freely". In my opinion, here lies the problem.
The former definition discusses functional movement (i.e. - reaching, rolling, crawling, walking, etc). The latter touches on the available "access" to movement. When some say that stability precedes mobility, it is likely that they mean stabilization must occur before functional movement can take place. When others say that mobility precedes stability, it is likely that they mean a degree of access to movement must first be present in order for stabilization to be necessary. So, it isn't that these two ideas are in conflict, the parties are missing each other because they are not speaking the same language.
Think about the differences in the skeletons of an infant and an elderly individual. The infant's structure is extremely pliable, where as the elderly's structure is rather stiff. This lends itself to what appears to be contrasting inherent problems. The infant, full of mobility, is likely to have issues/challenges with stability. The elder, with acquired stiffness, is likely to have problems with mobility. Breaking down the communication barriers enable us to see that these are just problems along different spots of the same continuum of functional movement.
The continuum of functional movement is as follows: access precedes stability which precedes functional movement. Access is the ability of a segment to assume the desired position(s) passively. Stability is the ability to maintain and/or resume/restore that desired position. Functional movement is the ability complete a desired tasked (i.e. - reaching, rolling, crawling, walking, etc).
Now let's go back to the infant and the elder. The normal infant, full of mobility, has all of the access to movement one would need. The next step in his/her quest for functional movement is to gain the necessary stability to harness that access into the appropriate position to allow for the desired movement. The average elder, with acquired stiffness, has to some degree lost his/her access to movement. He/she must restore the required access to passively allow the desired position before focusing on stability and thus functional movement.
This debate is largely an issue of semantics. In their own right, each side is correct. Now that we have "cleaned" up the semantical issue(s), the following two concepts should be clear:
- A person must have the required access passively to assume a desired position before one can expect them to perform a functional movement that requires that position.
- A person must be able to stabilize and thus control that access actively before one can expect them to perform a functional movement that requires that position.
The quest for wisdom is not about the assimilation of information. It is about information that brings about revelation. Revelation that can serve as a point of reference to guide you about your way. May this article be that for you. Godspeed!
Dr. Michael Davis, DPT, ART is a Doctor of Physical Therapy, Certified Active Release Technique Provider, Intramuscular Therapist, and Certified Kettlebell Instructor. He has treated high school, collegiate, recreational, and professional athletes of various sports including basketball, baseball, boxing, football, golf, martial arts, soccer, tennis, and track and field. In addition, he has experience in the in-patient neurological rehabilitative and acute care settings. Mike is a former NCAA athlete, a Hall of Fame Kettlebell Beast Tamer, and an avid power lifting and martial art enthusiast. He can be contacted via email at [email protected].
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