Wednesday, July 21, 2010
To plantarflex? To dorsiflex?
Ankle sprains are a prevalent among anyone spending time on not-asphalt. Not-asphalt is a very special surface, not seen a whole lot these days. It primarily consists of dirt, sticks, rocks, and (unfortunately) beer bottles. Not-asphalt presents a very special problem to the average joe... it's not flat. This lack of flatness present the not-asphalt user with a special challenge, namely how to not "explode" their ankles.
Plantarflexion and Dorsiflexion are two special motions that the ankle joint it capable of. Basically, plantarflexion is ankle towards the ground, dorsiflexion is ankle towards the ski. Up vs down. Terra firma vs the realm of stinging insects. Just what position should your ankle be when it makes contact with not-asphalt?
To make this simple as possible, we'll present a simple scenario. While trail running, our extremely talented runner is presented with a particular technical section of trail, littered with rocks the size of lunch boxes. Our runner is forced into a situation where he or she knows that their next step must be actually onto a rock. The rock is sloped on the near and front side, allowing our runner the option to meet the rock in either a dorsiflexed or plantarflexed position. What to do?
Most go for the plantarflexed position. It presents an easier way to push off, doesn't mess up stride that much, and puts them into an incredibly dangerous scenario, and let's be honest... that's more fun.
Plantarflexion at the ankle actually puts the talus and tibial plafond/fibular distal process (really fancy words for "ankle") into a position of less stability. The talus is tapered in the back, so when it's plantarflexed the ankle has a few millimeters more to roll in. That's not good. This causes ankle injuries.
I believe that it is best to hit the rock with the foot in a dorsiflexed, up, position. This gives the ankle more stability, which greatly decreases the chance of rolling the ankle. It's not practical in all situations, but it really does help the runner who is plagued with ankle injuries. The running stride feels a little out of place, and you have to make sure you make contact with the knee partially flexed (should be anyways), but the safety factor makes it completely worth it.