Tuesday 1-31-2012

“You Look Ridiculous!” The Benefits of Running in Gorilla Feet.

(or as we know them Vibrams)

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.

On Lieberman’s website: http://www.barefootrunning.fas.harvard.edu/index.html, he discusses barefoot running in an evolutionary context. Lieberman theorizes that around 2 million years ago the human foot changed from a flatter arch to a higher, springier arch allowing humans to improve long distance or endurance running. The possible explanation for this evolutionary change Lieberman elaborates in another article also published in Nature (Nature. 432: 345-352.) that I will attempt to summarize in the following: Lieberman suggests that as the African landscape changed around 2 million years ago, endurance running may have given humans an edge over other animals in the search for food. Whereas quadrupeds or 4-legged animals are much better sprinters, giving them an apparent evolutionary advantage, a bipedal or two-legged animal that could not necessarily sprint but could sustain a decent pace and ultimately tire the quadrupeds out and kill their prey. One important fact that Lieberman points out is that four legged animals cannot pant while sprinting. This makes it very difficult for them to cool their body and makes them susceptible to overheating.

In my opinion, combining the bio-mechanics of the foot with historical evidence and evolutionary context provides a solid case for the potential health benefits of barefoot running. I, however, do not run barefoot. I wear five finger shoes or Gorilla Feet, as I like to call them. Currently, the only company I am aware of that sells them is Vibram. I have no financial interests in this company. These Five Finger shoes preserve the biomechanics of the foot while providing protection from glass and rocks that one may encounter on the road or sidewalk.

Ultimately the choice is yours whether to run in heel-cushioned shoes or gorilla feet. If you enjoy running in heel-cushioned shoes and are not experiencing any discomfort I would recommend you continue to do so. If you are experiencing discomfort while running and would like to try something new, please be careful. I know from personal experience that if you push your workout too far in Five Finger shoes, you can pull or tear the weaker, less used muscles needed for barefoot running and cause delays in your training. On the Vibram website, you can find a practical guide to transition from traditional running shoes to Five Finger shoes and as always, check with your doctor before making and major changes in your exercise routine.

Important Disclaimer: (The idea that running shoes may be making our foot and leg muscles weaker also explains why it can be so difficult to transition to barefoot running. Both Warden and Lieberman caution you the reader to be very careful when or if you decide to take the running shoes off. Transitioning from running shoes to bare feet can take weeks to months to years. When transitioning, consider running one-tenth of your current distances with 1-3 days of rest in between.)

Max Rep Push Press
recovery of: 15e uni leg/opp arm KB deadlift
60 Box Jumps
30e Russian Twists
30 Overhead Squats (95/65)
30e Russian Twists
30 Chinups
30e Russian Twists
60 Air Squats
30e Russian Twists

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