First of all, let's set the record straight. Man is a natural long distance runner. Despite impressions to the contrary foisted on us daily from our predominantly sedentary and "well-fed" modern lifestyle, it is interesting to note that for long enough distances a well-trained human can outrun just about any other creature on the planet.
Of course, recognizing the health benefits of exercise, not all of us live a sedentary life, and running has become a popular form of physical activity. In addition to the exercise aspects, however, those of us with a competitive or goal-oriented nature, from the elite athlete to the recreational runner, might be interested in running faster. Obviously accomplishing a 5K personal best or qualifying for the Boston Marathon requires a solid training program and a substantial amount of hard work. But what about those incidentals that might enhance our ability to train and thus augment our performance on race day? (We're not talking about performance-enhancing drugs here.)
That's where the video comes in.
Running is a complex biomechanical phenomenon and this advertisement caught our attention because the design of these innovative shoes appears to seriously take some of the science into account. We are not endorsing a product here (especially since we haven't actually tested the shoes yet), however, let's analyze some of the issues presented in the video.
The major feature that separates these shoes from most other standard running footwear is that they force the runner into a mid-foot to fore-foot landing on each stride. Most running shoes have a large well-cushioned "heel counter" that makes it possible to strike the ground heel first without damaging the foot. While we do naturally walk heel first, it is true that heel striking is an inefficient way to run. Apropos of the video, let's apply Newton's third law. In order to land heel first, the foot must make impact in front of the center of gravity of the runner. This requires that the heel is going to push into the ground with a component of that force in the forward direction. The ground will then exert an equal and opposite reaction force, which means that there will be a braking effect on each stride. A mid- to fore-foot landing is going to take place more directly underneath the runners center of gravity alleviating this undesirable hindrance to forward motion.
In fact, consider the following: Man evolved to run barefoot, and shoes arrived on the scene only in the last few tens of thousands of years or so. Try running barefoot some time (preferably on a softer surface like grass) and pay attention to your foot strikes. You might find that it's almost impossible to land heel first. Your command central (your brain) just won't let you do it. Too much jarring. Your bare heel isn't designed to handle that pounding. The evidence supports that landing nearer the middle to front of the foot is the most efficient way to go. However, heel strikers should be advised that it might take some time to retrain your gait so that this feels at all natural. Trying to reform too quickly from a lifetime of heel striking could be a recipe for injury.
Finally what about those "actuator" thingies on the bottom of the shoe? The claim (put in more specific physics terms) is that they store elastic potential energy upon compression which is transformed back into kinetic energy upon push-off. While it is undoubtedly true that this must be happening to some extent, just like with a bouncy ball, the question remains as to what magnitude of an overall effect this could actually have. Let's do a rough estimate:
Exhibit A: The kinetic energy of a 75 kg runner moving at a speed of 4.0 m/s = ½ mv2 = 600 Joules.
Exhibit B: The amount of energy stored in a highly energy efficient spring (spring constant k = 1000 N/m) compressed a distance x = 1.0 cm (.01m) = ½ kx2 = 0.05 J.
Based on this calculation, it shouldn't surprise us that most of the elastic energy stored and released during the running motion takes place within the muscles of the body itself. The elastic properties of the shoes appear to be incidental and probably aren't going to make a lot of difference!
Nevertheless, one out of two ain't bad, and these shoes do represent one of the more interesting innovations in running shoe technology to come around in a long time.
Adam Weiner is the author of Don't Try This at Home! The Physics of Hollywood Movies.
Just give me something to wrap around what Mother Nature gave me. www.vibramfivefingers.com/
Another good one from Adam Weiner. He is perhaps the best writer on popsci.com today. He's not some nerd sitting behind the computer postulating about data. He actually knows what he's talking about it. It wouldn't surprise me if he's a pretty good runner in his own right.
That was an interesting article. I wonder why they would write an article about a product without reviewing it, though. Also, I felt the article needed a little more copy editing. I really wanted to replace the commas in the second paragraph's independent clause (, not all of us live a sedentary life,) with dashes. Actually, that whole sentence is awkwardly phrased. Oh well, at least the content is good.
I look at these shoes from the perspective of a true barefoot runner. I have been running exclusively barefoot for almost five years. So I have some questions about this 'natural' shoe.
Why does the toe-box curl upwards? Natural feet rest flat on the ground. What does the upward curl do to the natural movements of the foot? I can only believe forcing the toes of the foot up like that will constrict their natural movements, and will create an artificial stress in the arch of the foot.
Why do those shoes have such a large, built-up heel on them? Natural feet have the heel resting at the same level as the toes and the mid-foot. The video claims there is no need to heel-strike with these shoes -- so why have the big balloon on each heel? Having the heel built-up like that almost guarantees that it will get in the way, almost forcing a heel strike.
What kind of arch support do these shoes have in them? The arch of the foot is designed to flex, contract and expand with each step. If there is an "arch support" in the shoe, then it will interfere with this natural movement and weaken the foot's arch action and strength. Since I have been running barefoot, my arches have become more pronounced because I am actually using them when I run.
I am fascinated by the shock absorption claimed by the little pockets in the forefoot. How much shock can they really absorb? When I run barefoot, I have the benefit of my natural shock-absorbing arch in my foot, my Achilles tendon and calf muscles, plus I have the benefit of up to many inches of bending in my knees if necessary. From my perspective, that little bit of shock absorption contained in about 1/2 inch of space or material just doesn't compare. Proper running technique uses all of the body's natural shock absorbers, making the 1/2 inch of artificial absorption in the shoe unnecessary.
I would be much more interested in a shoe that had no heel whatsoever, and a flat, flexible sole. If they could whack off that bulbous heel, and flatten out that toe box, I might be interested in giving the modified shoe a test run. But - would I BUY it? I run naturally for free - it costs me absolutely nothing to prepare my feet for running. Those (modified) shoes had better offer me something really impressive to make me want to fork out $70-80-90 or more for them.
Ryan, if I understood right, you are basically saying that if they flatened All Stars more they would make better running shoes?
*goes out for a run in my all stars*
I don't know if flattening All Stars would make them better running shoes. What I am saying is that its odd for a shoe maker to claim their shoes promote a "more natural" running style, yet they include so many un-natural characteristics in their design.
What is "natural?" I think bare feet are the most natural thing we have for running. It stands to reason that shoes that try to come close to natural should be true to bare feet -- no artificial curves, curls, arches, uneven surfaces, pinching, fat bulbous spots, and they should be lightweight with flexibility. I think simple aquasox might be better shoes for running in than the hyped up expensive versions we see.
In fact, I told a 65 yr old retired dentist about my barefoot running. He had to stop running because his knees were giving him too much pain. He tried wearing aquasox, practiced the barefoot running forms I taught him, and he was able to resume running again. In just a few weeks of practice, he could run from two to three miles per run, three times a week. He was ecstatic that a simple pair of aquasox did more to help him run successfully than the thousands of dollars he had spent on chiropractors, podiatrists, orthopedic doctors, massage therapists, and on the many various shoes and orthotics he had purchased.
Some of the best runners in the world are the Tuaharama Indians of the Mexican highlands. They run races that last up to three days and nights and cover 150 miles. Their choice of footwear are simple flat sandals they make themselves, called Huaraches.
I purchased a pair of Newtons to test them out. They are in essence a traditional running shoe in every way with the exception of the 'lugs' under the forefoot. The intent is to help a runner transition from heel-strike to forefoot touch. The concept has the right intentions but imho the execution is mediocre. Disclosure: I am a barefoot runner. I personally run in simple leather moccasins (Soft Stars) which are super wide in the toe area, have zero cushioning or support and feel great.
Barefoot Runner & Instigator since 2002
www.barefootrunner.com : blog
www.skorashop.com : minimal footwear project
I recently read a brilliant article where long distant runners are now going bare feet or with just a slim sole underfoot. The argument is that they gain speed as the foot is lighter. I dont disagree with this, however, the running surface would need to be perfect to avoid any mishaps.