Post by robertisaacs on Nov 22, 2007 9:53:44 GMT
Quote:Kinetic chain correction or autosuggestion and the well documented ideomotor mechanism could all have a role here. Call me a miserable, cynical, closed minded g*t if you like (i'm used to that) but i remain unconvinced.
Ok you miserable, cynical.....
Lets have a look at how I see it working (simple way).
With any pronatory action a percentage of internal tibial femoral rotation occurs to a greater or lesser degree which yes has an effect on the pelvis and thereby the rotation of the spine thereby giving instability = poor posture.
Enter Darth Tatar with the orthotics
Stj stability , internal tibial /femoral rotation stabilised, pelvis stabilsed in Saggital plane ie the pelvis is thrust forward or backwards( thrust forward in pronation correction) ( try it yourself by moving your feet from maximum Abduction to maximum Adduction note pelvic movement) thus allowing the spine to lock correctly giving a more upright posture.
How many times does the Pt volunteer "I feel Taller, or my shoulders feel they are back and I'm upright" Loadsatimes here (not through suggestion other that "do you feel any different?")
Better posture = better control of chest muscles ( Stable spine to pull on ) better lung function = pts comment on boob job
So simply put, does that help to make you convinced ??
Cheers
Derek
That would be no. ;D
There should be a smilie of somebody rubbing their hands together. insert that here.
Right then. Kinetic chain theory. I had this one rammed down my throat by my old boss for 8 years. I broadly understand the concept ( i think) i just don't entirely buy it.
The concept, if i have understood it correctly is that orthotics effect a reduduction in Sub talar everison and dorsiflexion thanks to altered GRF. Consequently, assuming a traditionally obligate triplanar relationship between the movements (which, BTW is a big ass assumption) they also effect an external rotation in the tibia. Move past the knee and assuming that the rotation is preserved (another big ass assumption) we reach the hips. If the relationship between hip external rotation and pelvic tilt is as you say (and i'm not overly convinced about that either) the pelvic position is altered, the spinal position is changed (locked correctly?!) causing an improvement in posture.
I have several reservations.
1.
Various studies have examined the effect of orthotics on sub talar frontal plane movement (which is the plane in which orthotics primarily work). Some have found no effect
BLAKE RL, FERGUSON HJ: Effect of extrinsic rearfoot posts on rearfoot position. JAPMA 83: 447, 1993.[Abstract]
BROWN GP, DONATELLI R, CATLIN PA: The effects of two types of foot orthoses on rearfoot mechanics. J Orthop Sports Phys Ther 21: 258, 1995.[Medline]
whilst others have noted a small but significant effect
STELL JF, BUCKLEY JG: Controlling excessive pronation: a comparison of casted and non-casted orthoses. The Foot 8: 210, 1998.
GENOVA JM, GROSS MT: Effect of foot orthotics on calcaneal eversion during standing and treadmill walking for subjects with abnormal pronation. J Orthop Sports Phys Ther 30: 664, 2000.[Medline]
Relationship Between Positive Clinical Outcomes of Foot Orthotic Treatment and Changes in Rearfoot Kinematics
Gerard V. Zammit, BPod(Hons) * and Craig B. Payne, DipPod, MPH
Now these studies are Kinematic rather than kinetic. However if we are examining the effect of rotation (a kinematic variable) on the upper body surely kinetics have little role to play.
To be honest i struggled to observe the pelvic movement you spoke of, i look forward to us doing some demo's at the get together. We'll have to get the bonyest attendee to bring some cycling shorts. However even the most generous of these studies speak of really rather minor kinematic changes and i struggle to believe that such small rotational changes can effect such apparently large upper body changes.
I too have observed the "i feel like i'm standing straighter" phenominum often (although feel it would improve my understanding to see the gym instructor with big boobs, could you set it up?). However i'm reluctant to ascribe that to direct kinematic changes without some more data. There are other factors which could be at work here.
1. Exteroceptive (which brian would cause proprioceptive
) signals from the feet. With a casted (or indeed simple) device there is more information reaching the brain about GRF... the area of the foot in contact with the "ground" is increased by between 25 and 40 % (based on my study of those pressure paper thingies). This means the patient is more aware of the ground position and the forces acting on the feet.2. Good ole common or garden variety placebo action. Don't knock it or underestimate it. Theres no shame in it.
3. Most people when "trying" their new orthotics stand with feet paralell at shoulder width in something very much like heicho dachi or an "at ease" stance. You see very few people doing this in "real life". As such the effect might be tied to the standing position rather than anything else
4. Usually people are little aware of their posture. When they try your insole they are very aware of it. Ideomotor response is a powerful thing. If i suggested that your lower molar teeth started to ache they might well do so. Especially if you started to salivate more as the increased blood supply to your mouth starts to have an effect. It might start as a dull ache or a hot sensation aroundthe roots of the teeth. Some people fin that the whole lower jaw feels heavy or tired. Sometimes it takes a few hours to happen but other times it becomes quite throbby straight away. Doing anything for you?
5. I have an abbreviation for a condindition i suspect we all see, IMH. Iatrogenic malignant hypertonia. Simply put this is what happens when we put insoles in a patients foot which they feel "uncomfortable" or "unstable" with. They start to walk with higher muscle tone in the extrinsics and develop pain from muscles which are tense when they should be relaxed and feel pulled. Patients often complain of sporadic pains around the legs which may move and be inconsistant with the direct effect of the orthotics. The flip side of this might be IBH, Iatrogenic benign hypertonia, where the awareness of something "different" in the position of the legs / feet / wherever causes an increase in the core stability muscles as the patient subconciously protects their balance in an unfamilier situation. This, i suspect is a part of how MBTs work. Ironic that both MBT's (which destabilise) and Orthotics (which stabilise) both claim to improve core stability and balance.
There is other stuff but thats enough to chew over (if your teeth take it) for now.
I'm not saying that the kinetic chain model has no validity. I'm just not prepared to upgrade it from "could be but not prepared to claim it as fact" to "yep thats observable and empirically proven." That said there are very, very few things which make it into that catagory for me!
Regards
Robert
Beautiful people are inside out.
