Some honest movements across the big toe. Things you need to know as a runner or walker.
Lets see how good you are at this gait game at this point.
In the video above you should see two things: you should see me manually dorsiflexing / extending the big toe / hallux. I am creating extension through the 1st metatarsal joint (1st MTP). Essentially I am passively engaging the Windlass Mechanism of Hicks. This mechanism is essentially a biomechanical event that wraps the end of the plantar fascia over the metatarsal head and 1st MTP joint. So, when a person raises the heel in gait a moment of dorsiflexion/extension occurs across the joint. In the video you see me lifting the toe but in the closed chain event the toe stays on the ground and foot moves up and over the toe but the resultant motion at the 1st MTP is the same. It is still dorsiflexion / extension of the big toe about the 1st MTP joint.
This wrapping or winding of the plantarfascia around the joint causes the distance from the heel to the ball of the foot to shorten and thus creates an elevation of the arch of the foot (smarter than using an orthotic to push it up huh !) but this mechanism also raises the talus and supinates the foot. This action makes the foot more rigid and stable. After all, when you are raising the heel and progressing over the ball of the foot don’t you want a rigid lever to press off of ?! Ask any sprinter and they will concur. However, this mechanism occurs in all folks who have a relatively competent foot and 1st MTP joint.
What you NEED to see in the video is the additional motion up the limb. Watch the video again. When the toe is extended (dorsiflexed) the arch rises but the limb also externally rotates. You can see this by the subtle drift of the blue dots on the limb. We want and need this external rotation to occur at the hip and through the limb because remember, the limb was internally rotated as we passed our body mass over the foot. This is a normal gait phenomenon.
Here is what we want to you to ponder. Imagine a person with:
- a weak extensor hallucis mechanism (both longus and brevis: EHL, EHB)
- a hallux rigidus where the toe does not fully extend to that magical 45+ degree range or
- if the arch of the foot is so far collapsed and pronated
IF any of these things go wrong, then a sufficiently rigid foot is not formed for push off propulsion, an incompetent arch results and insufficient talar motion and external limb rotation will occur. This means that several subsequent biomechanical events will/ may be compromised including but not limited to:
- contralateral arm swing
- sufficient engagement of the gluteals for stablization and propusion since optimal external hip rotation will not be met
- inadequate pelvis posturing for spine neutrality
- etc. this is potentially a very very long list
Our take home point here is simple. You must have:
- sufficient and relatively symmetrical bilateral big toe extenion (hallux dorsiflexion) to optimize the Windlass Effect
- you must have sufficient strength of the toe extensors to gain and stabilize this joint range at the 1st MTP joint
- you must have both of the prior 2 in order to properly posture the foot and arch for rigid terminal loading response
- and you must have all 3 to sufficiently externally rotate the limb at the hip to engage the propulsive components of the gait cycle.
There is so much more we could have added to this brief blog post, including hallux impingement, hallux valgus and bunion formation, supination insufficiency syndromes, tibialis posterior insufficiency syndrome, metatarsalgia etc. The list is endless.
Hallux dorsiflexion, both passive and active range of motion must be checked on every athlete and client you see. Otherwise gait is likely to be impaired locally and globally from subtle insufficiencies.
Shawn and Ivo
The Gait Guys