Tuesday, May 3, 2011

The Interossei Muscles of the Foot (Why Barefoot Running is Booming)

The interossei muscles of the foot have two layers, a dorsal layer and a plantar layer.  They are conveniently named dorsal interoseus and plantar interoseus and are the deepest layers of the foot.  (There are four layers.)  There are four dorsal and 3 plantar muscles.

They lie between the metatarsals and have some interesting properties.  The first dorsal interoseus has attachments into the peroneal sheath and some have attachments into the long plantar ligament.  They have extensive fascial connections into a lot of soft tissue around them.

Why is this important?  In two words, Shock Absorption.  Warren Hammer describes it best.  During gait, at forefoot strike, the metatarsals spread out, this in turn loads up the mechanoreceptors in the interossei muscles.

The information relayed from the mechanoreceptors in the interossei muscles as they spread out cause a reflex contraction of the quadriceps. This contraction stabilizes the lower extremity muscles.  This is known as the positive supporting reaction.

This is one reason barefoot running has been such a boom lately.  Why you hear such revelations about all of a sudden after going barefoot, my lowerback pain is gone.  Hip pain is gone.  Calf pain...ect.


Ultimately, what you can take away from this can be summed up with one recommendation.  Don't wear tight shoes that don't allow your forefoot to expand.  Without room for the toes to spread, the initial impulse from the interossei muscles don't occur and ultimately shock absorption is inhibited.


Anonymous said...

I believe that I have an injury to the interosseous muscle between the 1st and 2nd toe---the pain and tightness are on the medial side of the 2nd toe which, I guess, is right where this muscle attaches. I have also had swelling, pain, tightness and discoloration on the top of my foot from the 1st to the 3rd metatarsal. The ortho said I had a stress rxn in the 2nd met but that's been 3 months ago so I expect that has healed. I still have pain (although slowly getting better) and a small amount of swelling on top of foot. Bottom line: what is the treatment for an injury to this area? Since I recently isolated this exact spot, I have been icing, massaging and stretching---but is there anything else I can do to possibly strengthen the muscles and get back to 100%. I haven't been able to run for 3 months. Thank you.

Unknown said...

Sorry to hear about your injury, in suffering from the same but it's been 9 months for me and the Dorsel Interosseous between toes 1 and 2 are still sore. I even had an MRI which apparently didn't reveal anything. Kind of out of things to try. Has yours healed? Did you learn anything to help you speed up the healing process?

Yousi said...

I think I have the same. MRI didn't show anything and I am in my 4th month. All I read is going non-weight bearing for 6 weeks but my Dr doesn't agree even though he doesn't know what is wrong. Any advice ?