Barefoot in the park
An evolutionary lens
Hominins, of which homo sapiens are the only surviving species, walked and ran barefoot over natural terrain for more than 2 million years. During that time, natural selection favoured anatomical and functional changes that maximised efficiency and minimised the risk of barefoot injury. This was a profound evolutionary pressure upon which our survival depended.
Archaic homo sapiens appeared in the hominin time-line ~300,000 years ago, and true homo sapiens ~150,000 years ago. By then, given we had survived such a long evolution, the forces of natural selection had sorted out barefoot running. Its underlying characteristic was to strike the ground with the forefoot and then lower the heel to the ground.
Around the 1970s, we decided we were smarter, and the cushioned running shoe made its appearance. Fundamental to its design was a cushioned and raised heel that both promoted heel-strike and protected from its consequences. The shoe heel created the problem, then tried to fix it.
Shod heel-strike mechanics:
The heel makes contact with the ground. The force of impact jars because of the small contact area. The foot is in front of the body’s Centre of Gravity (CoG) and the leg is extended with minimal knee flexion. This rigid arrangement transfers the force of impact to the knee and hip which have to absorb it and are thereby stressed. The force of reaction (rearwards up an extended leg), opposes forward motion. The torso is somewhat bent forward to adjust CoG, tightening the hip flexors. The only way this can be all made to work is to add additional cushioning via a shoe, and this running style depends on that technology. It is impossible to run barefoot with a heel-strike. I tried it for this post, and my whole body SCREAMED STOP immediately.
Bare forefoot-strike mechanics:
The forefoot/midfoot makes contact with the ground. The force of impact is minimised by being distributed over a larger area than for the heel. The calf engages (eccentrically) and gently but quickly lowers the heel onto the ground. The impact is minimal. As footfall occurs approximately under the CoG, the leg can be a little bent enabling the knee to absorb force through flexion and minimising transmission to the hip. The force applied to the leg does not impede forward motion because the leg is not so much in extension. The torso is more upright because ground contact is more in line with the CoG.
Injuries
Objective evidence for the safety of one of these running styles over the other, especially for recreational runners, is not yet available, and to settle this with rigorous science is fraught with complications and may never eventuate to everyone’s satisfaction.
However, surveys of recreational runners, presumably mostly shod, indicate that one-third to one-half are experiencing an injury at any given time. That is a huge proportion for a species that’s survival depended on being adapted to running.
What about the barefoot dangers of hard surfaces or glass etc? Our ancestors dealt with it —penetrating thorns, prickles, biting insects, hot rocks, uneven hard surfaces, unpredictable terrain. An injury could be fatal. We survived. Just be aware of your environment. Heightened awareness and sensation add to barefoot running. It’s remarkable how quickly and effectively our foot reflexes react to an unexpected encounter.
Performance
At an elite level, there is little to distinguish performance between the two styles, however there does seem to be a small advantage in barefoot running that may be simply due to the reduced weight carried by the foot, rather than technique.
Barefoot used to be more popular even for elites. The first man to win consecutive Olympic marathons (Abebe Bikila, 1960/64) ran both races barefoot.
The sound of silence
It’s silent running because it’s low-impact. Politely clear your throat when approaching people from behind who don’t expect you, so as to not startle them. The next time a shod runner passes you on a road, take note of the noise. That noise is a result of physical shoe impact with the ground, which the shoe has to cushion to reduce impact on the anatomy of the foot/knee/hip.
Barefoot shoes
The title is an oxymoron, but that’s how some minimalist shoe companies promote their brand. These shoes have no raised heels, and thin flexible soles, attempting to mimick barefoot. They have a use when you’re obliged to wear shoes for social acceptability or other reasons.
Social acceptability
A significant impediment to barefoot under many circumstances, not just running. Irrational but powerful. Persist anyway.
Hands
Have you noticed the similarities between our hands and feet? Large thumb/toe, other extremities diminishing laterally, same number of digits, both have heels. The thinking is that our genes primarily evolved to modify the foot because of the advantages of ambulation, but that the hand shared the same genes and followed along. With time we evolved to adapt the hand to other uses but it was secondary to the foot. In contrast to the foot, bare hands are of course socially acceptable.
Footnote
As adults, we rarely get to experience, or attend to, the ground under our feet or its variety (we may be barefoot at home but not elsewhere). There is a richness of sensation, as well as dexterity and strength, that is being muffled by footwear.
And yes, I couldn’t resist adding a footnote.
Further reading
Lieberman, DE (2012) . What We Can Learn About Running from Barefoot Running: An Evolutionary Medical Perspective
