I have been hearing about and seeing more posterior tibial tendonitis lately and they almost all had one thing in common – they were all almost all in runners who were forefoot strikers. There was a mixture of Chi running, Pose running and minimalist running which all require forefoot striking. The main claim as to why you should transition to one of these running forms is to reduce the impact that comes with heel striking. They certainly do, but what you don’t read or hear about very often is the forces that are increased by forefoot striking. One of those forces that increases is the need for the posterior tibial muscle to work harder. This obviously predisposes to posterior tibial tendonitis.
The challenge then is to treat posterior tibial tendonitis. Firstly the load that the tendon is placed under needs to be reduced. Foot orthotics dothis that really well. Just how well will depend on how much force is needed to reduce the load. Reverting back to heel striking is also going to help reduce the load.
What happens long term is a decision that next needs to be made? Stay heel striking or revert to forefoot striking? Some people can transition back and do not need their orthotics anymore and the posterior tibial tendon can adapt to the load if the transition is gradual. Others try to transition back and the loads are so great, that the tissues cannot adapt and need to keep wearing the orthotics and keep heel striking.
How do you pick which one is which. It is difficult, but a good guideline is the location of the subtalar joint axis. The more medial the axis, the greater the lever arm, the grater the load through the tendon, the less likely they can adapt.
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