Posterior Tibialis Shin Splints... what are the biomechanics and how to ward off injury?

Shin splints in their truest form are micro fractures on the tibia - or stress fractures, a shin splint in it's basic form is a painfull shin and has many causes. You mention the fact that you don't have flat feet but then mention that you don't know if you over pronate, pronation in excess is flat feet (again in basic language, your foot can have an arch at rest but the lose the arch when you weight bear through it that's over pronation and that's what doctors do normally call flat feet.)
As for you mentioning tibialis anterior, versus posterior, tibialis posterior sits at the back of the tibia connecting it to the fibula, where as the tibilais anterior is on the front of the tibia and connects into the interosseus membrane that goes between it and the fibula. In effect they both cross that same area, although the posterior one is larger and therefore, theorectically takes the greater load, (so you can't really hurt one rather than the other), it does contribute towards plantarflexion, but not hugely so as you have gastroc,soleus and plantaris there.
Personally I would go and get assessed by a physiotherapist to see if you have any major problems (one could be unstable ankles - the tib post pulls the ankle bones together when your foot points down increasing stability)where are you based?
Bascially try calf raises to strengthen the posterior, but do it on the edge of a step and lower past the edge of the step to stretch it aswell. However I would still go and see someone - my ability to see through the web is rather limited!!!

Posterior shin splints are caused by excessive or incorrect contraction of the tibialis posterior muscle and occasionally the flexor hallucis longus.

Tibialis posterior dysfunction is usually associated with excessive pronation. Pronation differs from flat feet. Flat feet refers to medial arch height which doesn't always have a bearing on foot function. For example, some feet test up really well in cultures that traditionally have very flat feet. Pronation occurs as a method of absorbing shock at impact. Some people excessively pronate that can lead to biomechanical dysfunction.

To see if you excessively pronate, put a pen mark on the bump on the inside of your foot just above your medial arch (navicular bone). Sit with your knees bent and measure the height of this mark from the floor. Then stand and measure the drop the occurs. If this fall is more than 3mm then you excessively pronate.

Most issues deriving from the big toe are caused by functional hallux limitus. This is where the 1st toe fails to passively extend during weight bearing. To test, stand on a phone book with your toes hanging over the edge. Lift one leg up and have some one try and extend your first toe (big toe). If it doesn't extend in this position you have a limitus problem.

Finally, Tib Posterior is also a funny muscle that seems to react to any form of dysfunction of the adrenal glands.

Do the tests and let me know how things show up.

Dr. Trev

Changing the lives of great athletes and great people