Tuesday, March 20, 2012

Human KERS

Anyone following Formula 1 car racing will have heard of "KERS" or Kinetic Energy Recovery System. It basically converts the braking energy of the car into stored energy so that it can be reconverted back into a useful power boost. One of my favourite applications is in this weird vehicle - the Thrustcycle - which stores mechanical energy.


The key to efficient use of the human body for walking, running, cycling or skiing appears also to depend upon a form of KERS and in this case it's the body's system of tendons and ligaments that do the job. Interestingly, car technology uses either flywheels or batteries to store energy - but the human body uses elastic force. Evolution has amazing capacity to find efficient solutions for problems - so it's a safe bet that our bodies do this job more efficiently than an F1 car. Perhaps energy can't be stored on the scale needed for a car through "elasticity" but it would seem to be incredibly inefficient converting first of all into electrical, then chemical (battery) then back again.

Information Physics
I have a great deal of difficulty with the terminology used in physics - such as "kinetic energy" or "potential energy". They help us to calculate and build things but otherwise they don't really make sense - at least on their own. Even the word "energy" doesn't make much sense and it can't really be defined or pinned down. I'd change the name KERS to PIT - Potential Information Transducer. The most concrete thing is the universe is "information" and when we look at things from that perspective then they can make a lot more sense. What a KERS system does is convert (transduce) momentum into a re-organised (information) chemical structure (battery). The Kinetic Energy is Potential Information and here the information is captured in chemistry. The information can be re-converted back into momentum, in which case it is Kinetic Information - or it can stay in the battery where it remains as stable Structural Information (Ref: Professor Tom Stonier). This is just a different way of perceiving the same thing - but it makes sense of the world around us although it is currently weaker as a method of quantifying things.

Transducer
What does all this mean to us? The human body is the most effective known information transducer known in the universe. The brain is part of this body. A human brain without the rest of the body would not actually do anything at all because all of its perceptions are based upon the physical senses.Without the senses it would be like a computer with no interfacing - completely useless and inert. Our internal universe is constructed relative to our experience of the outside world. A new born child has fully functioning eyes and brain but is blind until the world is explored through play.

Running
When the runner's foot lands on the ground - with a mid to forefoot strike, the shock is absorbed by the tendons and ligaments. The stride extending and opening up behind pulls the hip backwards and twists the spine up to the rib cage as the shoulder and arm work in the opposite direction. All of this energy stored in the tendons and ligaments is then released generating a rebound and pulling the leg forwards using the hip flexors. Forward propulsion comes mainly from gravity making us fall forwards. The hip extensors (glutes) - extending the leg behind stop the centre of mass from losing height as it moves forwards. This ultra efficient exploitation of gravity and internal energy recovery mechanism, combined with our ability to sweat and to carry water (hands), makes the human being the most effective running machine on this planet. Remove cars and the epidemic of obesity would rapidly disappear. We are also very lazy by default.

Cycling
In Cycling the foot is not static on the ground as the body passes over it - it's the other way around. The extension of the leg still demands the same action of the core and hip so we have to learn to pull the hip backwards as the leg extends against forwards against the pedal. Likewise the muscles in the foot have to be made active to compensate for the lack of sharp reflexive response with the progressive loading - so that the movement pattern resembles that of the foot and ankle in running. This coordination permits a strong use of the core muscles both in pushing down and pulling up on the other side at the same time. The power is internal and it's probably an error to try to use gravity and the weight of the upper body to pedal.


Cadence
In both running and cycling it is often heard that the ideal cadence is 180 strides per minute (90 cycles as measured on a bike). Muscle/tendon elasticity has a resonant frequency in this zone which makes it most efficient. With an elastic band - if you stretch it the band will remain in that state until you release it. Tendons have a brief window of about 1/3rd of a second where they function like this and if you are too slow then the energy and information dissipates as heat. Inefficient systems produce heat. I see that all the time when skiing and my clients are sweating buckets while I'm not even warm. Using ChiRunning technique to climb a hill compared to a heel striking/push-off stride would show a similar difference in body heat produced. It's probably not an accident that top athletes don't have to drink or eat much during a performance - they are so efficient. Just recently I realised that during a steep descent when running it was necessary to maintain the same mechanics  (contrary to explained in ChiRunning where he disappointingly reverts to a heel strike). The KERS system of the rotating core - tendons, ligaments and muscles around the spine - then appears to function as a great energy capturing device that dissipates most of the energy absorbed in slowing you down. It isn't the legs acting as a brake - it's the KERS system acting as a brake. Normally even walking downhill a long way is unpleasant because the quads end up burning. Walking with Chi technique eliminates this problem. This would indicate that the solution to descending is to lengthen the stride behind and reduce the cadence. Interestingly my body informed me of this solution - very counterintuitive - a long time before I could understand why. Normally when descending we do exactly the opposite and reach far ahead landing firmly on the heel (often twisting the ankle). However when walking down steps we never land on the heel and we don't reach far ahead - we slowly lower ourselves directly over the foot that has been advanced.


Skiing
Traditionally, for short turns especially, the body was meant to "coil" against the direction of the turn and then recoil, driving the skis into the new turn - or swinging them around in the air. The foot slides in skiing - just as it does in cycling - and so pulling that hip back in the middle of the body is as act that needs to be learned. The spine twists lightly in the same direction as the turn and the recoil is now used to realign the legs and upper body during the transition from one turn to another - not as a twisting force against the skis. Most of the time the motion in skiing would be like descending in running - we absorb and dissipate the energy. If the mechanics are wrong then this once again is all dealt with by the quads and they rapidly burn out. The spine also suffers great shocks and is soon damaged. When core KERS system is used then the energy is dissipated safely. For sharp very fast turns such as jump turns, short swings, short radius pivots or short fast carved turns then the KERS energy can be tapped for snappy recoil and rebound actions.

Life
In all the cases mentioned here there is a structural organisation of the body - a basic physical pattern. This pattern exists through the way in which Kinetic Energy (Potential Information) is harnessed and used to reorganise the body. This Kinetic Energy converts into Structural Information through intelligent coordination. If the coordination is good then the conversion is efficient and effective. Get the right structure and the body is being given a present that it responds to by adapting in a constructive way - building strength, mobility, flexibility, elasticity, power, vascular circulation and generally good health. Get the wrong structure and you end up with a damaged and broken structure - with bad health. Appropriate and efficient transduction between energy and information in both directions is the key to effectiveness and longevity. This process is what the ancient Chinese referred to as Chi. It flows through the body when coordination is correct. Not a single molecule in your body is "alive" - but life is tied to the organisation and pattern of those molecules. Structural information is the structure of life itself  - and it is fed through various forms of energy that are potential information. We call something "living" if it is able to continue this process of transduction. Seeds that have been stored for thousands of years either dry or frozen are seen to be in "suspended animation" - life having been suspended.  Someone can die and then be re-animated if the delay is brief enough that structure does not decay.

We can get power - therefore information - from metabolising food in our muscles and brain. We also have gravity as an external source of motion - or rather the elastic force of the ground preventing it. Meanwhile we can store energy and release it again within our system of tendons and ligaments. We can create efficiency through more effective leverage with better mechanics. The human KERS is the ignored part of our system but it is also the part we need to understand the deepest.

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