“You Look Ridiculous!” The Benefits of Running in Gorilla Feet.
By Dr. Christopher Ogilvie
If you walk into a sports store today, the number of running shoes available to choose from is overwhelming. Since its inception, the running shoe has evolved and the technology has improved to the point where many running stores are now able to video analyze how you run and recommend the perfect running shoe, based on gait, pronation, and width of your foot. It hasn’t always been this way though. As a matter of fact, before 1970, and the previous 2 million years or so, humans did not have the benefit of the heel-cushioned running shoe, the creation of which has caused us to completely change how we run. The question is; which is better?
The majority of shod runners, or runners wearing shoes, strike the ground with their heel (heel-strike) and the mid-foot (middle of the foot) and forefoot (front of the foot) landing a split second later. Heel-strike running is a relatively new phenomenon. Prior to the invention of thick, heel-cushioned running shoe, humans ran very differently. To see how, all you have to do is take your running shoes off. Heel-striking barefoot is quite painful. As a result the body will naturally adjust to a mid-foot strike or forefoot strike.
The reason the body naturally uses a mid-foot or forefoot strike can be found in the bio-mechanics of the foot. The human foot is shaped like an “L”. On the back of the “L” we have our Achilles tendon and calf muscles, and on the front we have the muscles of the foot. Additionally, we have vertical rotation of the foot around the ankle. To see this, point your toes down, then, bring your toes up towards your shin. Total range of motion is anywhere from 30 to 80 degrees. Essentially we have springs in our feet that allow our “L” shaped base to absorb the impact of our bodies landing on the ground and pushing back off again. The heel-strike negates the spring-like bio-mechanics of the foot and transfers the impact of landing to the thick cushion of the shoe, and the joints of the body. The reason running shoes have such thick soles is to accomplish what the bare foot does naturally; take the impact away from the ankles, knees, and hips.
Researchers from Harvard have been investigating this very topic. Harvard researcher Daniel Lieberman and his research team have published an article in the journal Nature (Nature 463: 531-5.) and found that “By landing on the middle or front of the foot, barefoot runners have almost no impact collision, much less than most shod runners generate when they heel-strike.” Impact collision is the initial force of the body landing transferred up through the body. Lieberman goes on to say that “it might be less injurious than the way some people run in shoes.” The article illustrates that when a barefoot runner strikes the ground, the impact collision is not absorbed by the heel and transferred to the ankle, knee, and hips, but is changed to rotational energy of the pointed foot touching the ground and with the help of the calf muscles and Achilles tendon, slowing the impact and easing our landing. The assumption here is that muscles and tendons can absorb impact better than bones and joints. Lieberman suggests that “evidence that barefoot and minimally shod runners avoid [heel-strike] with high-impact collisions may have public health implications. The average runner strikes the ground 600 times per kilometer, making runners prone to repetitive stress injuries. The incidence of such injuries has remained considerable for 30 years despite technological advancements that provide more cushioning and motion control in shoes designed for heel-toe running.” Lieberman admits that evidence of “reduced injuries in barefoot populations” is merely “anecdotal” and that more research is needed.
Similarly, at the June 2nd, 2011 American College of Sports Medicine meeting in Denver, Colorado, associate professor and director of research in the Department of Physical Therapy at Indiana University-Purdue University Indianapolis, Stuart Warden, explained in his symposium “Barefoot Running; So Easy, a Caveman Did it!” that “the heel cushions and arch supports within modern shoes have made our feet weaker”. This is true of any biological process in the body, if you don’t let the body do it, it will atrophy. This is understood to be an adaptive process that eliminates unnecessary or overly redundant biological functions. If you’ve ever worn a cast, you remember that when you took the cast off, the muscle underneath had atrophied.
