Part1, Part2, and all the others are on my Run Your Age blog – definitely should be read in order 🙂
According to research by a group of researchers at Harvard, a natural running gait consists of one that includes a forefoot or mid foot landing. This landing style is one that naturally absorbs the impact resulting in a body that does not have to deal with the impact. Examining the modern running shoes themselves, it is easy to see a large cushioned heel which promotes an aft foot landing. This aft foot landing allows the shoe to do several things, including align the foot throughout the stroke, reduce or remove pronation, and provide a level of comfort on the ground. These changes to the landing are counter-intuitive to how the foot itself is designed. The most basic method for testing this is to take your own shoes off and try jogging around. Even in the dirt and grass, this is not a comfortable feeling. Taking it a step further and looking at what happens when the foot strikes is revealing. On an aft foot strike, the ankle is pointing the entire foot upwards and all of the weight of your body is pressed onto the heel.
There is no load of your body distributed to the arch of your foot or any other component of your foot. As the rest of your foot begins to land the arch begins to share in the load of the landing and the ankle changes how it is flexing to allow the leg to move forward of the ankle. This combination of loading the arch and changing the flex in the ankle is called pronation. Finally the ankle changes it’s flex again for liftoff and the calf muscles and Achilles tendon shorten, the arch recoils, and the toes flex. This final movement causes the upward and forward motion of the body. Compare that movement to the fore and mid foot strikes (with our without shoes on), the initial landing is somewhere on the outside of the foot, generally centered on the ball of the foot (however, this varies by person and variances in exact landing are made by individuals for comfort). When the foot lands, the ankle is pointing the foot generally towards the ground and the toes are slightly elevated. The ankle begins to flex the heel towards the ground letting the calf and Achilles tendon absorb the load and energy of the movement.
Throughout this process of landing, the arch is participating in the load absorption. As the heel lands, the arch fully flattens and pronation occurs. This is roughly the same point in time that pronation occurred during a heel landing; owever, this time the pronation is reversed and occurs from forefoot to aft foot. The final movement is also the same; however, there is a difference here as well, at the beginning of the landing, the Achilles tendon absorbed all that energy during the stretch of the heel towards the ground. During the liftoff that energy is released as the tendon shortens just like a rubber band. (Lieberman, Venkadesan and Daoud)
With information like this available it is easy to see why running styles and training have evolved in recent years to ensure the art of running is not lost. The one thing that all of the running styles seem to have in common is a focus on body positioning and foot landings. The art component of running certainly rests here on how fluid the landings are, how enjoyable the foot stroke is, and ultimately how the pain is accommodated for. In the example of running with high tech running shoes developed in the last forty years the solution to handling the pain of running is to add cushioning and foot controls within the shoe. In the example of running without the use of high tech shoes that has been developed and refined in our body during the last hundreds of years the solution to handling the pain of running is to slightly adjust individual foot landings and take a break from running when it gets to be too much.
What is interesting about the definition of running as we know it today is that it is a result of two different types of evolution; the evolution of the body and the evolution of the running industry. The evolution of running, at least the portion of running that seem to result in our body being able to run, stems from our ancestors having a need to run long distances during hunts. (Liebenberg) Over time, this requirement to run long distances to provide food for the family and tribe acted as a cultural motivator for the body to evolve into a more efficient running machine. The running industry, being that it only cropped up in the last forty years or so has not had as much time to evolve, nor enough time to determine how useful the evolution is to our ability to run. What is known about running is that it is unique to every person. There are some generalizations about the form of running, but just like all art is unique to all individuals the movement of running is as well. For this reason, it is important to examine how our bodies are designed to move and what feels comfortable for us when we are running and then look at the running industry to see if there is anything useful there to enhance our natural abilities. There certainly may be, after all humans weren’t meant to fly, but the flight industry has done wonders for our ability to get up into the air and explore, calculators have done wonders for our ability to compute numbers, and plastics have done wonders for our abilities to advance society. With all of these indicators that our bodies have evolved to run and our desire to enhance that ability, as evidenced by our continued expansion of a running industry, the question of the benefits is left open. Are there any measurable benefits that are a result of running? There are a few things that are not generally argued. Running is something that nearly anyone can do, running is good for the body (lowers HDL, promotes bone strength, and results in a healthier lifestyle at older ages), and the way a body moves and the tools one uses to cause the body to move can vary drastically when one considers what occurs when one runs. Another less explored area of running benefits is the level of life satisfaction and satisfaction of family life. One would think that running; especially committed runners who run a lot would have a lower quality of family life due to their being out running all the time. That doesn’t seem to be the case; however. It seems that runners who are committed to running are runners that have a higher quality of life. (Goff and Fick) This is in line with what has been stated throughout this paper, running is an art that evolved in our bodies over thousands of years. Running can’t be placed into a neat definition because it is so unique for everyone yet collaboratively based on the same principles. I would say that the definition of running includes your personal implementation of an ancient act that has evolved over thousands of years, it includes how all of the bones, muscles, and tendons work together to cause your body to endure the movement or not, the personal feeling and emotion that is wrapped up in the run, and today may be enhanced and measured by a number of tools in the industry. Obviously this is much different than the common definition of long strides and both feet momentarily off the ground, but running is more than just long strides with both feet momentarily off the ground.
Bramble, Dennis M. and Daniel E. Lieberman. “Endurance running and the evolution of
Homo.” Nature (2004).
Goff, Stephen J. and Daniel S. Fick. “Training Levels and Perceived Benefits Of Running
Among Runners Commited to Both Running and Family versus Runners Commited Exclusively to
Running.” Journal of Sport Behavior (1997): 387-397.
Liebenberg, Louis. “The relevance of persistence hunting to human evolution.” Journal of
Human Evolution (2008): 1156+.
Lieberman, Daniel E., et al. Biomechanics of Foot Strikes. n.d.
Sellers, Irvin William, et al. “Evolutionary Robotic Approaches in Primate Gait Analysis
.” International Journal of Primatology (2007): 321-338.