Monday, March 9, 2009
Peroneals, Hallux Limitus and Ankle Sprains
The peroneals are the muscles along the lateral aspect of your calf. They are very important stabilizers of the ankle, but also important for the proper function of the big toe as well. (hallux refers to big toe). How many times have you heard a million dollar athlete is sidelined from "turf toe?" How many know individuals that complain of having, "weak ankles?" They just give out on me!
The peroneals have a concentric and eccentric role. During gait, as your heel leaves the ground, there is dorsiflexion at the big toe joint (metatarsal-phalnge joint MTJP) and plantarflexion at the ankle. This causes what is known as the windlass mechanism, basically, it tightens the fascia on the under surface of the foot and plantarflexes the first metatarsal. Now, the peroneal longus stabilizes the first metatarsal against the ground during all of this, and causes a close packing of the calcaneo-cuboid joint.
Now, if there is peroneal inhibition or weakness, there will not be the ability to stabilize the big toe, thus one reason hallux limitus (big toe doesn't move) can occur. Now there are also other roles the peroneals play. They act as a counter balance with the posterior tibialis muscle. They work together to stabilize the foot. The peroneals evert and plantar flex, the posterior tibialis inverts and plantar flexes. Again, if we have peroneal inhibition or weakness, the posterior tibialis muscle will over power and put the foot into an inverted position, thus ankle sprains.
So there are two powerful reasons to spend a little time in strengthening the peroneal muscle groups!