Friday, February 12, 2010

Cadence

Cadence is a very important aspect of Pose Running Technique. Each foot should touch the ground 90 (or more) times per minute.  At higher cadences the tendons in the legs are able return as much energy to assist with muscle contraction. I'll explain further.

Tendons are like elastic bands in that when they are stretched, they store energy. In other words, stretch a tendon and it will snap back to its original length. Tendons are unlike elastic bands in that the stored energy dissipates quickly after they have been stretched. So if you keep a tendon stretched for too long, it snaps back with less power. For example, if a runner contracts his or her hamstring muscles, the tendons in the quadriceps are stretched storing some energy, and if the runner then contracts his or her quadriceps fast enough, the energy stored in the tendons of the quadriceps will assist in the contraction.

Why a cadence of 90 or more? The properties of our tendons have predetermined how long they will store energy. There may be some variation from person to person; however, I have noticed that this cadence of 90 consistently pops up in running and biking literature, so it seems to be widely accepted.

In my experience, most people run at a cadence of 80 to 85 steps per minute before they learn Pose Running Technique. As a result, these people are not getting the full benefit of the energy stored in their tendons. After learning Pose Technique, most people find it relatively easy to reach a cadence of 90 steps per minute. The reason for this is that they are spending much less time executing each step. Most people go from 5/30ths to 8/30ths of second to somewhere between 4/30ths and 2/30ths of second executing each step from the landing of the foot to the start of the pull.

If you are interested, I'm using 30ths of a second as the unit of evaluation because the typical video camera has a frame rate of 30 frames per second, so running technique is usually evaluated in terms of this frame rate.

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