Dorsiflexion in Sprinting
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Dorsiflexion is the action of the ankle joint that brings the dorsal, or top region, of the foot upward towards your body. Flexion of the ankle or foot is another term commonly used to refer to dorsiflexion. The action is opposite of plantar-flexion, which is pointing the toes downward and extending the ankle. The primary muscles in dorsiflexion are the muscles on the anterior portion or the leg, the tibialis anterior (muscle in the front of the shin), whereas plantar-flexion is controlled by the gastrocnemius and the soleus (muscles of the calf). Dorsiflexion is emphasized in speed training and plyommetrics.
Studies show a correlation between speed and ground contact time. As speed increases, the time the foot spends in contact with the ground decreases. The idea behind training a dorsiflexed ankle position is so that the ankle keeps the foot in the best position to make contact with the ground and quickly “rebound” resulting in less time of the foot in contact with the ground. A fast runner needs to be able to plant their foot in a dorsiflexed position so they can get it off the ground as quickly as possible as to not slow themselves down. Many “specialists” suggest that training your foot to spend less time on the ground is the best way to improve your overall speed.
The idea of dorsiflexion sounds good, and it is in fact one of the biggest training standards for running technique in the modern speed training world. But, there is a flaw in this logic. Again, we are not saying that dorsiflexion itself is a bad idea in that it is essential to an efficient runners stride. The flaw comes in how practically all training programs approach teaching dorsiflexion. It is true that there is a definite correlation between foot contact time and speed. But, one of the biggest misconceptions, not just here but in many fields of study is that correlation equals causality.
Just because less foot-ground contact time correlates with greater speed doesn’t mean that training the foot to pop quickly off the ground will equate to greater speed. Less time the foot spends on the ground is not the reason sprinters run faster, it is the effect of running faster. It is simply a byproduct of your body moving faster. The faster you run, the shorter your foot will be in contact with the ground. Correlation, but not causality. Greater speed is attained by a greater amount of force applied to the ground to propel your body forward. This power is primarily generated at the hip joint, not at the ankle. A dorsiflexed ankle helps to transfer this force into the ground and therefore is a component of speed, but if you do not focus on increasing power from the hip, then all the dorsiflexion in the world will only make you so much faster. It is true that ankle dorsiflexion at the point of ground contact is the most efficient position for transferring the power generated in your hip into the ground and back to your body, but you will still only be able to run as fast as your body will allow depending on the efficiency and power of your stride.
Dorsiflexion should be naturally occurring movement as a result of an efficient stride. Stride efficiency begins at the hip, not the foot. When you train your stride to be powerful and efficient originating from the hip, then as you pull your foot through by driving your knee forward, dorsiflexion will occur as a natural movement of the ankle as you bring your foot down to make contact with the ground. The focus of you training should not be to try and shorten the time your foot remains on the ground by forcing a dorsiflexed position. This should occur naturally as your build an efficient stride from the hips down causing your speed to increase.
The focus of training programs should be on increasing hip power and efficiency. In the future we will be building programs that you can purchase that take your body through a progression that follows the 4 laws of training we have described that will totally redesign your muscular system starting at the hips, following the strength progression, as to fill in any gaps in strength and efficiency. Your hip strength, range of motion, and overall power will increase as a result, giving you the necessary tools to run with the most powerful stride possible.