Dorsiflexion

Why in the world would my first post be about dorsiflexion.  I guess because in all my years training, I’d never heard this word.  In fact, the training in “my day” was focused on pushing off your toes.  Not until I moved to Texas and trained with Dan Pfaff did any coach ever tell me to “pull my toes up” as soon as my foot left the ground (still didn’t use the word dorsiflexion though… 🙂 ).

Now-a-days, every good sprint coach knows about dorsiflexion, which promotes “front side mechanics”.  So, this seemed as good a place as any to start.

Loren Seagrave explains the advantages of dorsiflexion is his article “Neuro-Biomechanics of Maximum Velocity Sprinting” (link to SpeedEndurance.com’s file).

“To minimise the moment of inertia of the thigh, it is critical for the athlete to make the leg as short as possible, as soon as possible. This means that high angular acceleration values must be realized at the knee joint.  Dorsiflexion of the ankle joint accomplishes both these tasks. Occurring actively at take-off, dorsiflexion facilitates the triple flexor response.  In addition, it facilitates knee flexion by the gastrocnemius.  Use of stored elastic energy in the gastrocnemius and its high contraction velocity makes it possible to generate high values of angular acceleration at the knee joint.  The result is a short lever as soon as possible.  The ankle remains in dorsiflexion, which maintains a small knee angle throughout the entire Recovery Phase.”

So, basically, pulling the toe up (and more accurately the top of the foot) as soon as possible makes the whole hip and knee contract faster than with a pointed toe.  Moreover, Seagrave describes an EMG study that showed early initiation of dorsiflexion is positively correlated with how fast a sprinter runs.

“The timing of the dorsiflexion message to the anterior compartment muscles is of critical importance. MOUCHBAHANI et al. demonstrated that the dorsiflexion message was sent sooner in faster sprinters and much later in slower sprinters. The fastest sprinters showed EMG activity over the anterior compartment as early as mid-stance (when the centre of mass is over the base of support). This finding further validates the concept of anticipatory firing or reprogramming the athlete’s nervous system to send the dorsiflexion message sooner.”

“As early as mid-stance”!!!  That seems crazy.  So, the faster sprinter’s brains are firing impulses to their ankle/shine to dorsiflex well before their foot has left the ground.  Talk about the exact opposite of pushing off your toes.

Now, when I trained with Pfaff, this isn’t how he explained it to me.  He explained “toe up” as getting the foot in the perfect position to drive it forcefully to the ground.  And if it were in this dorsiflexed position at ground contract (which should be directly below you), you would load all the triple flexor muscles plyometrically, creating an elastic rebound effect (think rubber band stretching then snapping back).

If you’re a toe runner like I was, you completely miss out on any loading effect.  Moreover, you foot tends to hit the ground in front of you, causing a breaking effect — two strikes against you.

So, regardless of which is correct, or perhaps the both are.  Dorsiflexion seems to be of key importance in sprinting.

I still struggle with physically making my foot dorsiflex off the ground.  It’s not easy for an old dog like me.  So, I’ve been looking for exercise to help improve my own dorsiflexion speed.  Here’s a link that I’m starting to use:

http://www.bodybuilding.com/fun/ss6.htm

Hopefully this helps!  Good luck.