Scientific rumblings about whether running shoes deliver on their promises have been growing louder in recent years. In 2008, an influential review article in The British Journal of Sports Medicine concluded that sports-medicine specialists should stop recommending running shoes based on a person’s foot posture. No scientific evidence supported the practice, the authors pointed out, concluding that “the true effects” of today’s running shoes “on the health and performance of distance runners remain unknown.”
The problem with assessing your foot posture and then recommending a certain shoe type (cushiony/soft or supportive/rigid or middle-of-the-road) is that your static foot posture is not necessarily indicative of your foot rhythm in gait. I tend to overpronate on my right foot and yet I have very high arches. The shoe salesmen from this article would tell me I need a cushiony shoe because of my overpronation, and yet a rigid shoe for my high arches. See? Ridiculous. I'm proud of the researcher quoted at the end of the article because he recommends readers listen to their body and pick running shoes based on that. Yay! One point for our side! Researchers don't usually recommend kinesthetic awareness because they like to measure things, and subjective thoughts are impossible to objectively measure.
I'm barefoot most of the time because that's what Pilates instructors do, but when I do wear shoes I often pick my Vibram toe gloves. I just wish they were flesh colored, because I'm 5'2" and wear a size 9 shoe. I look like *$&%* Minnie Mouse.
Every step you take moves through a gait cycle. Look at the activity of the right foot: half of the time you are standing on it (stance phase) or swinging it forward and preparing for the next step (swing phase). The stance phase is made up of the following events: heel strike, foot flat, heel off and finally toe off. Here's an illustration of the gait cycle.
When the foot moves through toe-off (that's the second leg to the right of the shaded leg in the above illustration), normally the big toe is the last bit to leave the ground. The very last scrap of propulsion your body is going to get is going to come from this moment. Do you think the big toe can provide much oomph for the rest of the body? After all, it's not very big....
The big toe is ingeniously designed. Its tendons are long and thin so that the belly of the muscle is located much higher up, in the calf. This image is from Thieme's General Anatomy textbook. It's the mostest awesomest anatomy book ever. Go visit them at the winkingskull.com or buy it at amazon.
This illustration shows the muscle flexor hallucis longus (a long name like that describes the muscle - that is it flexes a joint, it's attached to the big toe, and it's very long) as well as some others. To find the flexor hallucis longus, look at the base of the big toe and follow that gray tendon upward, behind the inside ankle bone and toward the outside of the calf muscle. Look at how big the belly of that muscle is! It's extremely powerful (or at least has the potential to be). The larger the cross-section of the muscle, the more force it can generate. As in:
Sorry, I got distracted there for a moment. 'K, look at his shoulder, that is the muscle belly of his deltoid.
That's a muscle with a lot of potential for power, and it attaches directly to the bones it affects. There's no long thin tendon attaching it to a bone far away. The big toe's ingenious design allows our feet to be bony and light, and yet still have access to power. Like a long extension cord! If our feet had to pack the muscle in right on top of the bones, our feet would look like big pillows stuffed with sausages. Ick. Nothing fun like this would ever happen again:
Watch sprinters bursting out of the blocks at the beginning of a race; of course that power is coming from the posterior hips and thighs, but don't dismiss the contribution of the big toe and its flexor hallucis longus. For dancers, this muscle is essential for jumps and releves.
Many anatomy texts attribute balance to the inner ear, identifying the vestibular system as the organ of balance and equilibrium. But it's just one piece of the puzzle. Humans also rely on visual cues and on sensory information such as the sensations picked up by the soles of your feet.
Stand up with your feet about fist-width apart and close your eyes for a moment. Can you sense that your body is not completely still? You are swaying slightly, typically forward and backward, constantly adjusting your center of gravity over your feet. This oscillation is called postural sway and is the result of a feedback loop between your sensory system, your musculoskeletal system and gravity. It's completely normal. Now stand on one leg and close your eyes again. Did this sway increase? Could you keep your eyes closed for 10 seconds, balanced on one leg?
This gentle sway is present whenever you are in quiet standing, such as in line at the grocery. If you have "good" balance, your postural sway is likely to be slight and hardly noticeable. If you have "bad" balance, your postural sway is probably such a large oscillation you can hardly perform the closed-eyes balance without your eyes popping open and grabbing for a hand-rail.
Postural sway does not negatively impact quiet standing until one of the members of the loop is compromised in some way. We can safely assume gravity isn't going to develop an issue, so chances are it's the sensory or the musculoskeletal system. These two systems work together so closely to determine and maintain balance that they can be collectively termed the sensorimotor system. One system detects what's going on and the other corrects any problems: whoops I'm falling forward, I better get my weight back... whoops now I'm falling backward, I better get my weight forward.... you get the idea. People who have bad balance basically have a slow reaction to the shifting. By the time their sensory system has detected the shift of the center of gravity, and the motor system has organized a response, the person has already stumbled. Being drunk slows your motor system and that shows up as poor balance or slurred speaking (1:39 below - I love MST3K.)
Poor balance is as if your sensorimotor system was chronically drunk and this has a very negative impact on fitness. Many older adults reduce their physical activity levels because of a fear of falling (Lee, Arthur & Avis, 2008), and this lack of activity of course slows their reaction time even more. A negative spiral that will likely end with a fall, a hip fracture and a long stay in a nursing home. Yikes.
So what to do?
--Challenge your balance with every workout. If you don't work out, then add simple balance exercises to your day. Hiyamizu, Fukumoto, Kataoka, and Yagi (2009) found adults between 61 and 71 improved their postural sway by simply standing for 10 seconds each day for 10 days on foam pads of differing density. The subjects were asked to detect the firmness of the foam pads they stood on, thereby engaging the sensory system in an active way. At the end of the trial, the researchers found significant improvements in postural sway.
--Take a ballet class at the local community college. Don't worry, no one else is looking at you; they are all too busy looking at themselves. Dance is fantastic balance training and it makes your tush look good.
--Take a tai chi class. Good for your balance, good for calming the monkey mind.
--Facing a wall, stand on one leg. Watch an imaginary spider crawl up the wall, so that you tip your head up. Try to maintain your balance as you watch the "spider" go up and down a few times. Repeat on the other leg.
One of my favorites is the baby BOSU, it is one of the very best gifts for a 6-year old ever. My boy simply bounced on this thing for about 3 years. Tons of fun, and versatile for adults too because it provides the unstable training surface, doesn't take up so much room, and is cheaper than the larger version.
Reference: Lee, L., Arthur, A., & Avis, M. (2008). Using self-efficacy theory to develop interventions that help older people overcome psychological barriers to physical activity: a discussion paper. International Journal of Nursing Studies, 45, 1690-1699.
If you have ever slept on an arm and awakened with a “dead” hand, or sat too long with your legs crossed and had your foot fall asleep, you have some inkling of what many people with peripheral neuropathy experience day in and day out, often with no relief in sight.
Here's a nice explanation of peripheral nerve damage. As a Pilates and Gyrotonic instructor I come across students with this issue from time to time. If you are also a movement educator, it's good to understand this condition.
Finally! An article on barefoot running that is mostly science, and not all starry-eyed evangelists. I think barefoot running is a great idea, but I never thought it would make you faster... apparently some people do. In today's NYTimes - article here.
Daniel Lieberman, PhD, a professor of human evolutionary biology at Harvard University, studies and periodically practices barefoot running. His academic work focuses in part on how early man survived by evolving the ability to lope for long distances after prey, well before the advent of Nike shoes. There “is good evidence that humans have been running long distances for millions of years,” he says, “and most of that was probably done barefoot.” For his own part, “I run a lot,” he says, “and at least once a week, I run about three to five miles on the streets of Cambridge, completely barefoot. I can attest to the fact that it’s a lot of fun.”
Toes are hassled a lot. The ball of your foot bears a great deal of your weight while standing and is used like a hinge every time you take a step. This movement, between the metatarsals and the toes (the MTP joint) is called extension. Flexion is when you grip your parakeet perch with your toes or pick up Fritos from the floor.
The fantastic illustration below is from the wonderful Thieme people... you can preview their combined Atlas of Anatomy at www.winkingskull.com, and then buy it at amazon. It is very reasonably priced and I think it's the best anatomy text out there. It certainly kicks Netter's butt. (It is most definitely NOT Thieme's illustration above, that's my own ridiculous attempt of combining photography and illustration.)
So, walking moves your MTP joints through a neutral (or flat) position to extension, but not through flexion. As a result, your feet get a lot more practice with MTP extension than with flexion. With time and neglect, many feet begin to show MTP extension even when there is no weight on them - yikes! And that, little one, is the beginning of hammer toes.
Here's a fun article about gibbons and how their feet may provide clues as to how our own feet evolved. Two scientists from the University of Antwerp filmed a troop of gibbon feet at a wild animal park in Belgium and built a model of how their feet work. Gibbons walk like ballerinas: toes first!
Sometimes those darn calf muscles develop little spider veins. Ick. They distract the viewer's gaze from our feet! Terrible... and we can't wear tights year-round. Especially not here in Monterey where we are finally getting our two weeks of summer (we are 62 degrees F practically year-round) and it's our turn to wear shorts and capris and sandals! Except for yesterday when it rained a little bit.
Anyhoo, the NYTimes has a nice article today about what we can do about spider veins. Turns out that it's a very simple procedure: injection with a saline-based product is simplest, but laser is effective as well for needle-phobes. The Times also has a layout on possible herbal treatments, such as marigold and horse chestnut. Especially since your insurance is not likely to cover cosmetic treatments like this, perhaps we should all try the herbal treatments first.
Read the article and learn a new word! Telangiectasia. Sounds like a fruity cocktail made with an orange juice base.
The New York Times has a nice article in today's paper about the current thoughts on barefoot running and the chagrin of the shoe manufacturers.
The article also mentions the book Born to Run by Christopher McDougall which I read earlier this year. It's about the multiple injuries suffered by the author that drove him to discover the running style of the Tarahumara, a native Mexican-desert dwelling population. Running essentially barefoot, the Tarahumara are like a human gazelle/mountain goat and beat the pants off most competitors, especially in Ultramarathons like this one. (McDougall's book does spend a lot of time cooing over ultramarathoning and its stars. A little tedious for me, but surely a lovefest for those in the sport.)
If you've ever studied foot biomechanics (I promise you I am really a treat at cocktail parties. Really. I don't bore anyone.) you know there is a moment called footstrike or heelstrike when the heel initially touches down on the ground to begin a new step. In barefoot running (or gladiator-sandal running, or Chalcolithic-sandal running, etc) the foot doesn't strike with the heel, but with the mid-foot. This is essential for foot safety if you don't have any external cushioning on the foot. Only some of the shock-absorption capacity is in the heel; it can accommodate the energy/shock from walking, but not the increased impact forces from running. As a result, barefoot running is more upright than running in Nikes or Asics or whatever cushioned shoe you've got.
Here are Nike's Zoom Mawler Track and Field shoe. Look at the rearfoot area: it's thin with very little shock absorbing material there. Sprinters spend no time on their heels. Go to 1:12 and watch the slow-motion of the sprinter's feet. Their weight is not in their heels.
To me, the next question is do barefoot sprinters go faster than modern-technology sprinters, or is this paradox only applicable to endurance runners? I'm wondering if the Tarahumara put spikes on their sandals would it increase their speed?
