I recently received this email in my in box:

“I’ve been suffering from mild pain/ discomfort around the 3rd and 4th metatarsal heads on my right foot. This seems to have flared up after my last marathon in May, and it has never really died down. I get some relief, but not total relief, by placing a met pad behind the metatarsal heads.

Before I go further, perhaps some background info would help. I’m female, age 42, marathon runner. I have a neutral foot, and I tend to be able to handle high mileage (80-90 mpw). I have bilateral bunions that don’t hurt. I’ve had orthotics in the past, but no longer wear them. I wear a minimalist shoe for shorter runs (Nike Free 5.0)and a more cushioned shoe for long runs (Adidas Supernova Glide). I don’t appear to pronate at all on the right foot, but slightly on the left foot. The wear pattern on the bottom of the left shoe shows a circular pattern under the big toe. Finally, I had a tibial stress fracture on the right side last year.

OK,here’s my situation: Recently, I was experimenting with placement of the met pad on the right foot. I don’t know what made me think to do this, other than it just felt like a good idea, but I placed the met pad directly under the first metatarsal head (directly under the big toe on the ball of the foot).

I immediately noticed 2 things: First, my posture while running was greatly improved. I felt as if my right and left sides were balanced for the first time, and I had a sense that my arms were able to swing freely and evenly for the first time. It felt really good. Second, I felt as if my right foot was finally able to act as a lever upon push off, and I instantly felt I could run at the same pace using less energy (which translates to running faster). Oh! I also completely got rid of the met pain by doing this!

I feel as if I’ve stumbled on to something very useful, but I am a little afraid to mess my biomechanics as I’m just educated enough to know that when you do this you affect the whole chain from the ground up. I’d hate to end up with an injury further on up the chain!

Anyways, I was just wondering if you could provide any input as to why it would proprioceptively feel so good for me to raise up the 1st metatarsal head? Should I continue to do this, and if so, with what material? It seems like the harder the material the better.

In closing, it seems like I have a lot of “biomechanical clues”, but I need help interpreting them. I hope you can shed some light!

Thanks in advance-

PW”

PW is exactly right – there are many biomechanical clues in her report to me. All of the clues point at orthotics as a solution for her problem. The orthotics I recommended to PW based on the “evidence offered” is a device with a forefoot post. I deduced from this email that this person has a forefoot dysfunction that is resolved with a forefoot post (the met pad under the first ray).

The other clue is the wear pattern (the circular pattern under the big toe) also suggests that the foot is spinning before pushing off. this sometimes occurs when there is dysfunction in the foot that also points to a fore foot post as a solution.

The third clue is the tibial stress fracture. This usually occurs because the tibia is attenuating forces in an unusual fashion such that a fracture occurred.

With respect to biomechanics, my mantra is “Structure Governs Function”. If the Tibia is being overloaded AND the foot is spinning, AND a first ray post improves efficiency, THEN there is a biomechanical deficit that would be resolved with an orthotic device with a forefoot post.

The etiology of this dysfunction begins with embryonic growth and development. In the 8 week old fetus you can see the legs sprouting out of the trunk with the soles of the feet rotated so that they point “up”. As time passes, the hips rotate so that the soles of the feet are “down”. Depending on how much they correct to the right orientation (too little or too much), the feet end up with more or less pronation to begin with.

Remember that the foot has two jobs in life: First to be a mobile adapter, and second to be a rigid lever. In order for the foot to operate in this fashion, there is a mechanical effect called the Windlass effect which causes the foot to transform from the mobile adapter as it hits the ground, into a rigid lever for propulsion. The way this happens is that the ligaments and joint capsules bring the bones together as the heel comes off the ground and the plantar fascia along with the deeper structures allow the foot to become rigid enough to push you off into your next step.  So the foot travels through space and the joints are all loose allowing the foot to adapt to the surface, and as your body comes over the foot, the windlass effect causes the foot to become more rigid and propulsion occurs.

In the event one has a forefoot that is in a supinated position relative to the rest of the leg and foot, in order for that forefoot to get on the ground, it has to travel further in space, and this takes time too. Since the talus follows the calcaneus, and since the tibia follows the talus, this latent time period and longer journey of the forefoot causes the motion to be increased at the knee (frontal plane) , and even at the hip (transverse plane). In order to run, this process is often short circuited, and the foot, instead of transitioning on to the first ray so you can push off with the big toes, instead, the foot spins on the 2nd, 3rd, and 4th metatarsal heads and the foot rolls over the inside of the big toe (leading to bunion deformities of the big toes).

The long and short of it is that the foot with a forefoot deformity is an excellent candidate for orthotics with a forefoot post.

In my post The Case for Barefoot RunningI make the case for forefoot striking. Where someone has a forefoot dysfunction however, orthotics in shoes are preferable to barefoot running.

You can also read more about forefoot varus in this post from December 2008.

Neil