Does the tibia drive the foot or does the foot drive the tibia?

So why do some people pronate more when you put a medial wedge under the heel?

When you stand on a medial wedge, many peoples tibia does rotate esternally. But the research under discussion was about what happens dynamically.

If during dynamic function a medial heel wedge did externally rotate the tibia, how do you know that it was the effect of the wedge on the foot that affeected the tibia?

How do you know that all the wedge did was just lower the rearfoot inversion moment, so it was easier for the tibia to externally rotate and the tibia supintaed the foot as it was now easier to do as the inversion moment was lower? (which is a hypothesis that is more consistent with the finding of the research under discussion).

Have you read the paper under discussion?

 

Your profession being..... "amateur critic"?

"Taxi for Mr Nake"

 

Craig,
Did you write that last paragraph a little quickly? tibia supination?

My theory on the medial heel wedge is that it does cause a STJ supination moment, but in those feet with pronation range of motion, the incrased supination moment will make them feel unstable (inversion sprains) and the peroneal muscles will act to prevent inversion and end up pronating the STJ. The supination moment from the wedge is smaller than the pronation moment from the muscles in this situation.

Cheers,
Eric

 

As long as yu are drivin it and i will spoon feed yu with tips!!:deadhorse:

 

Hi Folks came across this, which is all about joint coupling.

Though it might add something to the debate.

 

I'm loving this discussion.

I became very interested in this exact topic when I read a study by Milner et al on tibial stress fractures. It showed significant differences in the free moment of 25 test subjects with a history of tibial stress fracture and 25 controls. I wonder how the power flow looks on people who demonstrate Adduction free moments vs Abduction free moments.

Does anyone know of a biomechanical study where transverse plane friction is eliminated without eliminating A-P or M-L friction. I'm imagining landing on a spin disc.

I play sport called broomball (for you non-Canadians that means running on ice) and I can't help wondering how much friction occurs in the transverse plane, as well as the other planes as I attempt to stop the one heel squeal. This follows a comment made earlier about landing in oil.

My take on the topic is power flows proximal to distal but distal structures, the foot, must adhere to the nature of the external environment. An orthotic in a shoe presents a specific external environment that dictates the body's response. If the neuromuscular response is not altered appropriately to the exact external environment underfoot then the body is in trouble. Of course I also believe a custom orthotic has the best potential to create an external environment which most closely matches an individuals optimal situation for efficiency, thus should also offload overstressed tissues.

Leopold

 

If you look at it from a gait point of view you do not get tibial rotation until heel contact. Then pronation occurs, and tibal rotation comences as subtalor pronation occurs. Surly preventing tibial rotation will prevent subtalor pronation in this case. Therfore so subtalor pronation causes tibial rotation, but tibial rotation can limit subtalor pronation.

 

I read this: http://ukpmc.ac.uk/articles/PMC2413410/ and thought of this thread.

 

Found this article related with this thread :

Review
Proximal and distal contributions to lower extremity injury: A review of the literature
Vivienne H. Chuter , Xanne A.K. Janse de Jonge
Gait & Posture 36 (2012) 7–15

A B S T R A C T
Excessive or prolonged foot pronation has been linked to the development of numerous overuse injuries affecting the lower limb. The originally proposed pathomechanical model suggests foot motion affects more proximal structures through disruption of distal to proximal coupling between the foot, tibia, femur, and hip. Research evidence supports the presence of a dynamic coupling mechanism between lower limb segments, however, the direction of the coupling is inconclusive. Recent prospective investigations of the role of the lumbo-pelvic hip complex have identified a strong association between proximal dysfunction and increased risk of lower limb injuries. Strength of muscles of the lumbo-pelvic hip complex (core muscles) is suggested to be essential to controlling hip abduction, subsequent internal rotation of the femur and potentially more distal movement. Proximal muscle weakness and altered motor control have also been implicated in the development of numerous lower limb injuries, many of which have previously been attributed to excessive foot pronation. This review discusses the theoretical basis for the role of proximal and distal structures in biomechanical dysfunction of the lower limb and the development of lower limb overuse injury. Current prospective evidence relating to the contributions of excessive foot pronation and core muscle function to the development of lower extremity injury is evaluated.

http://www.sciencedirect.com/science/article/pii/S0966636212000409

 

Re: Open letter to Craig Payne

Hi Jeff,

What you are describing is what occurs during 'Gravity Drive' when an unstable foot structure forces the foot to abnormally pronate during a closed kinetic chain.

Normally, e.g., without a structural deformity in the foot or lower extremity, foot motion is directed by the transverse plane rotations of the pelvis, referred to as 'hip drive'.

Brian

 

Re: Open letter to Craig Payne

Brian,

It has been some time since I posted that comment to this thread. As I recall (without reviewing the thread), my point was simply to point out that when open chain stj supination and pronation occur, the entire foot moves relative to the proximal segment (i.e. relative to the static talus and tibia). That is the very nature of open chain motion. If muscle contraction occurs and produces a stj moment that results in stj supination or pronation motion, the tibia won’t rotate unless the foot, distal to the stj, is in contact with the supporting surface. In this case, the proximal segment(s) move due to the fact that motion is resisted distally. For example if I supinate my foot in space, my entire foot adducts with stj supination. However, if I supinate my foot in a closed chain environment with my foot flat on the ground, my tibia must externally rotate in order to permit stj supination since frictional forces prevent my foot from adducting. I don't believe it has anything to do a stable or unstable foot, since a stable and unstable foot can both function in an open and closed chain environment. When I get some time I will review the thread to see the context of my original comment.

Jeff

 

Yes. Rob