Friday, September 30, 2011

Dynamical Analogies

I'm probably guilty of over using analogies in my daily life, I'm like a bulweavel in a.... see, there I go again!  But the "spring" can be used to represent anything.  One could string together a set of springs in a certain way to completely mimic the behavior of a building in an earthquake, or a table's jiggle'ability.  A spring's springy'ness or compliance is measurable, hang weigth from it and it extends only so far, it has a resonant frequency, etc.  these are all properties of the muscles and tendons in your "running chain" .  

The beauty of the springiness of your legs is that it's variable.  The engagement of muscles change tension, resonance, compliance of this spring.  It's a wonderful thing!  

Have you ever tried to run on a trampoline?  There's only one slow speed you can go other wise the springiness of the trampoline will push back so hard it can drive your knee into a tooth!  This is what's happening when you add 'springs' in series with your running chain.  Why would I insert a spring?  It's what you're doing when adding a springy cushion under your foot, or running on a rubber track, or spring loaded treadmill.  Cascading these compliances adds to your work load.  You are now in charge of absorbing your weight, absorbing energy returned at a different rate due to these dissimilar cascaded resonances.  

Remove the cushions and you will see!  It's less work, more economical, and more conducive to long term injury-free running.   (...more to come).

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