The efficiency of barefoot running style September 23 2016, 0 Comments
Our bodies have many wonderful ways of managing energy - for instance redirecting blood flow to conserve or disperse heat, and in the case of running, storing energy to be used in the next stride.
In their book on Biomechanics and Biology of Movement, the authors estimate that for a 70kg runner the energy lost and regained in each stride is about 100Joules. Of this, about 17 Joules is stored in the elastic tendons of the foot as the foot stretches and flattens on landing, and another 35 Joules is stored in the Achilles tendon as the heel is lowered to the floor. When springing off into the next stride, this elastically stored energy is used for the lift-off. You will notice that the assumption in this is that the foot lands with the ball of the foot first so that the heel can be lowered for this impact absorption.
Work done at Harvard has shown that the impact on landing during running is about two and a half times your body weight, and they have elegantly illustrated how this happens for different running styles. With a front-foot landing, as the impact absorption comes into play gradually there is a steady incremental impact, with a symmetrical decrease as the weight is lifted off again. With a heel strike, the elastic parts of the foot and Achilles tendon cannot play a part in impact absorption, and so there is a jarring impact which carries up through the joints of the leg. It is possible to run on the front foot with heeled running shoes, but it is less easy, and there is less travel to absorb the impact. Heel striking with padded shoes does not seem to have much effect on the jarring impact of the landing.
To switch to a front-foot running style may take a little re-learning (we do it naturally when we are children), but it will save energy by using your elastic tendons to help you run.
The days are cooling off now as we move into Autumn, so if you are thinking about saving energy by changing to barefoot shoes, check out our winter models, Apex and Hero, which are made from Thermoprene to keep your feet snug in the cold weather.