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.”
Sprint 42 