Tuning the spring for speed involves positioning your body to control both the amount and direction of the forces produced by elastic recoil. These forces are used to efficiently move you up and forward. This concept is very similar to the way the spring of a pogo stick compresses under the rider’s body weight then decompresses to move the rider up and forward.
Note: The techniques described in this article should only be attempted once you have successfully implemented the techniques described in the Reducing Effort and Impact at the Front of your Stride article. Therefore, you should be successful at minimizing the distance your feet contact the ground in front of your hips and are able to run with a tall posture, slight lean, as well as relaxed legs, knees, ankles and feet throughout your whole stride.
What is Elastic Recoil?
“When human tissue is stretched and released, it snaps back forcefully. This enables runners to store energy in the Plantar Fascia, the Achilles tendon, and the Soleus and Gastrocnemius muscles from one stride and return that energy as propulsion. Optimal use of elastic recoil is a major difference in efficiency differences between runners – Evolution Running”.
When your relaxed leg, knee, ankle and foot support your body weight at the front of your stride, it is analogous to a spring that is being compressed by your body weight. As soon as your hips pass in front of the support foot, this spring uncompresses to propel you forward.
You do not have to consciously contract your calf muscles and push-off the ball of your foot at the rear of your stride, instead you just leave the leg, knee, ankle and foot completely relaxed and elastic recoil happens on its own!
Initial Pressure Point
As soon as your foot contacts the ground at the front of your stride, the spot on the bottom of the foot where you first feel pressure is referred to as the “initial pressure point”. The location of the initial pressure point is determined by the location of your center of gravity. The location of your center of gravity is controlled by your body position.
If you imagine that your spring runs from the forefoot all the way to the knee, then the more forward the initial pressure point (towards the bottom of the spring) the more the spring compresses and the faster you go. The more rearward the initial pressure point (away from the bottom of the spring) the less the spring compresses and the slower you go.
Remember it is not about forefoot or heel striking. The whole bottom of the foot contacts the ground almost simultaneously; however the location of the initial pressure point can be changed.
Enabling the Spring
The first thing you must do is “enable the spring” by ensuring your knees and ankles are completely relaxed, otherwise the spring can’t compress and uncompress.
For a simple demonstration on what this feels like, stand tall, completely lock your knees and then hop up and down. You should feel the initial pressure point under the heels whenever your feet contact the ground. In fact with your knees locked you cannot move the initial pressure point away from under the heels. Stand tall with your knees completely locked and without hopping, feel that your weight is supported over the heels. There is no weight on the forefoot and you can actually lift the forefoot and toes off the ground while standing in this position with your knees locked.
Now stand tall, relax your knees and slowly start bending them more and more. As the bend increases, feel the pressure point move from the heels towards the forefoot. The point just before the leg muscles start to engage is the amount of knee bend you want. Remember you want maximum knee bend but you don’t want to work for it. When your knees are at maximum bend but still relaxed, the pressure point is underneath the forefoot and you can now lift the heels off the ground while leaving the forefoot in contact with the ground.
Now stand tall, place your knees at maximum bend, relax the ankles and start hopping up and down. You should notice much less impact and a little bounce when compared to hopping with locked knees. The impact is safely absorbed by your “spring” as it compresses and the bounce is a result of the spring uncompressing and pushing you upward. This is the feeling you want when running.
Tuning the Spring
Tuning the spring involves adjusting your body position to move your center of gravity forward or rearward which in turn moves the initial pressure point forward or rearward.
From a body position where you are tall with relaxed ankles and bent knees, leave your hips where they are and tilt your whole upper body forward slightly from the hips. Only the upper body moves forward. The lower body (from the hips to the feet) does not change position. Feel that your head is moving forward as you tilt the upper body.
Experiment with tilting the upper body forward and backward and feel the location of the initial pressure point move under the bottom of the foot. As you tilt the upper body forward the initial pressure point moves forward. As you tilt the upper body rearward, the initial pressure point moves rearward. Only make very small changes in your tilt at a time and ensure your neck is aligned with your torso and not bent forward.
When your upper body is at the right angle of tilt, you can further fine tune your body position by very slightly moving your hips forward or rearward. When doing this feel that your head does not move forward or rearward as you move your hips. This adjustment needs to be very slight otherwise it changes your upper body’s angle of tilt.
It is difficult to mistakenly tilt the upper body too far rearward since you will not feel the initial pressure point under the forefoot, instead it will be under the heel. However it is possible to tilt the upper torso too far forward in an attempt to gain more and more speed. This can put you in a position with too much tilt at the hips and may cause lower back pain or discomfort. If this occurs:
(1) First reduce the forward tilt slightly to eliminate the discomfort.
(2) Then ensure the ankles are relaxed and move the belly button forward slightly to increase whole boy’s angle of lean from the ankle.
Always ensure your neck is straight and aligned with the upper torso. You may need to slightly increase the whole body’s angle of lean if you are generating too much upward momentum and not enough forward momentum. A pogo stick will not move the rider forward if it is too vertical; the rider will just bounce straight up and down.
Practice the steps while standing still to feel how it works before trying to implement the steps during your run. You can practice the steps while barefoot to make it easier to feel the location of the initial pressure point and your body position’s effect.