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Designed for running August 18 2017, 0 Comments

We are designed to run, and a number of our design features passively help us to do so.

We've previously discussed the anatomical features that show how we have evolved as long-distance runners. Our long legs and impressively large buttocks give us a long, loping stride. Because we are bipedal, our stride does not limit our breathing in the same way as for four-legged animals. Our ability to sweat keeps us from overheating and enables us to outlast animals that can only cool themselves by panting. The nuchal ligament in our necks, which is not present in tree-dwelling apes, keeps our head stable while we run. And finally, strong elastic ligaments in our feet and achilles tendons store energy from our landing and re-use it in the push off into the next stride.

Professor Dan Lieberman eloquently explains and quantifies the passive elements of running in this short video, explaining that the arch of the foot stores 17% of landing energy, and the achilles tendon another 35% - energy that does not have to be generated in the muscles to contribute to the next step as it is released naturally by the springy ligaments. There are two conditions for this to work at its best - we need to run and land with good form, and we need to relax while we run so that our passive mechanisms can make their contribution.

So, shoulders down, easy breathing and a light, springy step in order to enjoy the countryside around you rather than focusing on the effort - after all, if you are doing it right, 52% of that effort comes for free.


How well are we equipped to run? - 2. Lower legs and feet. April 12 2016, 0 Comments

From our previous discussion, our upper legs are designed to help us with locomotion on the ground, and I'd like to now build the case that we are actually designed to run.

Casting our attention south to the lower legs and feet, and again comparing with the apes, we can see that we have a very chunky calf muscle and a considerably bigger achilles tendon.

Tendons connect bones to muscles and are elastic, often being placed to absorb and store energy for later use. For walking, where we normally plant the heel and then roll forward on the foot to pushing off into the next step, there doesn't seem to be much need for a large, impact-absorbing tendon. For running, on the other hand, especially if we accept the case for a front-foot landing, the absorption of energy as the heel is lowered warrants a very much larger tendon, such as we have. The elastic energy stored can then be used for the push-off into the next stride.

The case becomes stronger when considered with the structure of the foot. One of our feet has 26 bones, 33 joints and more than 100 muscles. Many of these are located in the arch, which acts as a bridge between the ball and heel of the foot. When we land on the front foot in running, the muscles in the arch and the achilles tendon together tense and absorb the impact of the step so that the heel lands much more lightly. This prevents a jarring impact at the heel being transferred upwards to the ankle and knee and the lower back. One of the best illustrations of this are the videos taken by Dr Daniel Lieberman's group at the skeletal lab at Harvard University. Follow the link for a heel strike. You can see that the total impact of landing is about two and a half times the body weight, when the heel lands about one and a half times the body weight occurs in the first, jarring impact by the heel, shown by a vertical line on the impact/time trace at the bottom.

With a front-foot landing, the impact trace has a much more gradual slope, showing a steady transfer of weight, rather than a sudden one. Furthermore, adding a big wad of padding to the sole of your foot doesn't significantly reduce the sudden impact of a heel strike.

So our calves, achilles tendons and feet are admirably suited to provide us with a cushioned ride during running. And we have other equipment that helps us to run, as we shall discuss in the next blog. In the mean time you might like to check out our  ZEMgear shoes, which protect your feet, but allow them and your legs to run as nature intended.

 


Do flip-flops cause floppy feet? August 04 2015, 0 Comments

Wearers of high heels sometimes complain of tiredness and aches when going barefoot or wearing flip-flops, and somehow this has been translated into a message that the flip-flops are the trouble makers.

We go barefoot around the house, and wear ZEMgear shoes regularly for trips to the shops or to go out socially. Our feet therefore regularly get exercise and stretching through everyday use - and on the occasions that we do wear flip-flops, it's a breeze!We would argue the opposite. If your feet are encased in a shoe all day, they are unable to flex and stretch as they would if they were uncovered, and so all the little muscles and tendons in the feet and calves do not get exercise. This is especially true if you are wearing high heels, where the foot is fixed in position such that up to 90% of your weight is resting on the ball of the foot. Furthermore, the Achilles tendon is held in an unnaturally shortened position, and tends to shrink. If, at the weekend, you then switch to flops, your feet will have to do unaccustomed work when you walk, and the Achilles tendon will be stretched back into its natural position, both of which can lead to discomfort. Regular periods in which you allow your feet and Achilles tendons to work naturally will help with this. We advise people new to barefoot shoes to start gradually, especially if the intent is to do some serious running, and allow the feet, tendons and calves to 'get fit' again.


The sock conundrum January 22 2015, 0 Comments

Despite a gradual improvement in fitness from running, by the end of last year I was having a nagging recurrence of slight inflammation in my Achilles tendons - not enough to stop running, but enough to make them uncomfortable for a couple of days.  I run with a group, and we stand around and socialise after the run, and I felt that the cold around my ankles aggravated the inflammation.

A two-week break at Christmas gave them time to recover, and I took a couple of other measures.  To quiet down my immune system and inflammatory response, I changed my diet to increase my intake of antioxidants and omega-3 oils with more fruit, vegetables and fish.  This was less an issue when I wore Heroes, because they reach higher up the ankles, but more so when I wore Apexes as there was a gap between them and my running pants.

I browsed toe-socks to address this, but then Claudia pointed out that we had a solution in our own inventory in the form of the HG ankle supports, and this proved to be very successful.  They are elasticated, offering some support, and more importantly in this case, keeping the ankles and tendons warm.  They work really well with the ZEMgear shoes, as they are effectively toeless socks.

It worked.  The achilles tendons are now quiet, and I am running freely and enjoyably through the winter chill.