A Questionable Case for Running Shoes


The New York Times Health section discusses a study from the University of Colorado in Boulder comparing the metabolic costs of running in shoes vs running barefoot.  The results suggest that shod running is more energy efficient than unshod running.  These results deserve a few questions.  First some background on the study. 

Subjects of the study were 12 barefoot runners–runners who knew how to run barefoot in contrast to novice barefooters.  “It was important to find people who are used to running barefoot,” says Rodger Kram, a professor of integrative physiology, who oversaw the study.

These runners were then asked to run several times in a yoga sock on a treadmill or while wearing the 150 gram Nike Mayfly, a lightweight running shoe.  Then the researchers taped 150 grams’ worth of thin lead strips to the top of runners’ sock feet. By adding an equal amount of weight to the bare foot, they could learn whether barefoot running or shod running was more efficient.  The study reports these findings:

1. For every 100g (3.5oz) (the average weight of a deck of playing cards) added per foot, energy cost increases by approximately 1% whether running barefoot or shod.

2. Running barefoot and in lightweight shoes do not significantly differ in energy cost.

3. When controlling for shoe/foot mass, running in lightweight shoes requires ~3-4% less energy than running barefoot.

So it seems that wearing a shoe is a good idea if you want to conserve energy as you run.  This would be important obviously during a race.  Here are some questions and observations:

1. The positive result of wearing a shoe was seen in 8 of the 12 runners.  That means 1/3 of the subjects saw no advantage from running in shoes.  Extrapolated out to a large population that means a significant number of barefoot runners are at no disadvantage running in bare feet.  I wonder if any of them are more efficient in bare feet?

2. The study was done on a treadmill.  Treadmill running is quite different from real running.  What if the study was done on a road or trail?

3. The study looked at the Nike Mayfly.  What about other shoes?  It’s a light shoe.  Would even lighter shoes be better efficiency?

4. A commentator on the Times article made the following observation: “Flaw: the only way for the comparison to be valid is if the weight distribution of added weights were precisely the same as the weight distribution of the shoes themselves. Anyone who has ever studied the effects of mass distribution on movement would know that.”

So did the way the weight was added to the (mostly) bare feet affect the runners’ efficiency?  What if the weight was distributed differently?

5. The study enlisted experienced barefoot runners as subjects.  Alex Hutchinson of Sweat Science and Runner’s World discusses that issue:

Finally, all the runners were midfoot or forefoot strikers, both barefoot and in shoes. This condition was imposed to prevent confounding effects from comparing rearfoot to forefoot striking efficiency.

These conditions raise an important caveat. One of the proposed advantages of barefoot-minimalist running is that it automatically helps to correct overstriding — an extremely common problem among inexperienced runners. The fact that all these runners were already forefoot strikes suggests that none of them were likely overstriding, which would make them less likely to benefit from barefoot running. It’s possible that a truly ‘random’ group of runners might have been less efficient in the shod condition, because more of them would have been dramatically overstriding.

It’s good that someone has done this study.  The debate isn’t over and it’s always good to have another view.  There’s plenty more studying to be done.

One thing that I keep coming back to is the fact that the fastest runners in the world wear shoes–at least when racing.  So from the performance standpoint there seems to be some benefit to putting something on your feet.  Further, if you’re happy with you performance and enjoyment of running then you should probably stay with what you’re doing whether it’s shod or unshod.

Orthotics Are a Mystery


“I guess the main thing to note is that, as biomechanists, we really do not know how orthotics work.”
– Dr. Joseph Hamill, University of Massachusetts professor of kinesiology

Orthotics.  Some people swear by them.  Some people swear at them.  (That would be me.)  Some of them cost a few bucks at the grocery store.  Others cost several hundred dollars and must be fitted at a podiatrist, physical therapist or chiropractor.  So what about them?  Do we need them or not? (And if they are important for our health, how did the Egyptians, the Romans, Gengis Kahn, the Vikings, etc. ever manage march across the earth and conquer everything in site without them?)

All runners and other fitness enthusiasts–anyone who wears shoes really–must read the latest dispatch from the New York Times Personal Best section titled Close Look at Orthotics Raises a Welter of Doubt.  It’s a fascinating discussion on how and why orthotics may or may not work.  As the quote above indicates, no one really seems to know what these things actually do for the feet.  There are several important points in the article.

Analysis of Orthotics

Dr. Benno Nigg, professor of biomechanics and co-director of the Human Performance Lab at the University of Calgary in Alberta has made a career of researching orthotics. He makes a point that I’ve observed in my own experience with orthotics, namely that they tend to work in the short-term.  However he says that idea that they are supposed to correct mechanical-alignment problems does not hold up.

Further Dr. Nigg says, “If you do something to a shoe, different people will react differently.”  Different feet react differently: One person might respond by increasing the stress on the outside of the foot, another on the inside. Another might not respond at all, unconsciously correcting the orthotic’s correction.

The article discusses something I’ve heard discussed among those who make orthotics.  That is, there are different ways to make orthotics.  Depending on where you go, you’ll likely get a different device.  Dr. Nigg conducted a study in which a runner went to several different orthotics makers and each one made him a distinctly different orthotic to “correct” his pronation.  He liked two of them–yet they each were made differently.  More research by Dr. Nigg yielded the following:

“They (orthotics) turn out to have little effect on kinematics — the actual movement of the skeleton during a run. But they can have large effects on muscles and joints, often making muscles work as much as 50 percent harder for the same movement and increasing stress on joints by a similar amount.”

“As for ‘corrective’ orthotics,” Dr. Nigg says, “they do not correct so much as lead to a reduction in muscle strength.”

Support for Orthotics

Several seemingly well-educated people voiced support for the use of orthotics.  Jeffrey P. Wensman, director of clinical and technical services at the Orthotics and Prosthetics Center at the University of Michigan makes a sound argument when he says the key measure of success is his patients feel better in orthotics.

(On that note, I think it’s wise that if you’re in an orthotic and feeling good, running fast and all is well, then don’t change anything.)

Seamus Kennedy, president and co-owner of Hersco Ortho Labs in New York says there are hundreds of papers and studies showing that orthotics can treat common foot ailments.

So maybe there’s a lot of solid evidence in favor of orthotics right?  Well… The article states:

“In one recent review of published papers, Dr. Nigg and his colleagues analyzed studies on orthotics and injury prevention. Nearly all published studies, they report, lacked scientific rigor.”

Maybe the lesson is to be skeptical of orthotics makers who show you evidence of the benefits of orthotics.

What About Flat Feet?

The article goes on to profile someone who has flat feet and his quest to “correct” this issue.  Every orthotics provider he went to attributed his injury to his previous poorly made orthotics and goes on to provide him with different orthotics.

(The article mentions this fellow has an “injury” though there’s no mention of what this injury is.  I’m not sure if we’re to take his flat feet as an injury.)

Dr. Nigg explains that flat feet shouldn’t be any problem.  Our arches are an evolutionary leftover of when we used to grip trees with our feet.  This is interesting to me because I recall reading elsewhere a study of third-world populations that never wear any sort of supportive shoes.  Their feet tend to be flat yet there are far fewer numbers of the type of musculoskeletal injuries we have in the U.S.  So maybe these all important arches aren’t all that important?

My view on all this is that orthotics are of limited use and the science behind them is quite murky.  I’ve used several different types of orthotics and I’ve had either no results or I’ve experienced increased discomfort.  I think they are far from an essential component for human health and performance.  That said, on an individual basis, an orthotic may be very helpful.

News: Food Addiction, Exercise and Colds, Rocker Shoes


Here are a few of the points on the scale that are used to determine if you have a food addiction. Does any of this sound familiar? If it does, you may be an “industrial food addict.”

Food Addiction

We’ve got several interesting fitness-related things in the news recently.  First, from the Huffington Post comes Food Addiction: Could it Explain Why 79 Percent of Americans Are Obese?  Here the food industry and its products are compared to the tobacco industry and their products.  Turns out our junk food is skillfully crafted and manipulated by the food industry to make it highly palatable possibly to the point of being addictive.  Key to the discussion is the following information from the article:

Researchers from Yale’s Rudd Center for Food Policy and Obesity validated a “food addiction” scale.(i) Here are a few of the points on the scale that are used to determine if you have a food addiction. Does any of this sound familiar? If it does, you may be an “industrial food addict.”

I find that when I start eating certain foods, I end up eating much more than I had planned. Not eating certain types of food or cutting down on certain types of food is something I worry about.

  1. I spend a lot of time feeling sluggish or lethargic from overeating.
  2. There have been times when I consumed certain foods so often or in such large quantities that I spent time dealing with negative feelings from overeating instead of working, spending time with my family or friends, or engaging in other important activities or recreational activities that I enjoy.
  3. I kept consuming the same types of food or the same amount of food even though I was having emotional and/or physical problems.
  4. Over time, I have found that I need to eat more and more to get the feeling I want, such as reduced negative emotions or increased pleasure.
  5. I have had withdrawal symptoms when I cut down or stopped eating certain foods, including physical symptoms, agitation, or anxiety. (Please do not include withdrawal symptoms caused by cutting down on caffeinated beverages such as soda pop, coffee, tea, energy drinks, etc.)
  6. My behavior with respect to food and eating causes significant distress.
  7. I experience significant problems in my ability to function effectively (daily routine, job/school, social activities, family activities, health difficulties) because of food and eating.

Based on these criteria and others, many of us, including most obese children, are “addicted” to industrial food.

Here are some of the scientific findings confirming that food can, indeed, be addictive(ii):

  1. Sugar stimulates the brain’s reward centers through the neurotransmitter dopamine, exactly like other addictive drugs.
    Brain imagining (PET scans) shows that high-sugar and high-fat foods work just like heroin, opium, or morphine in the brain.(iii)
    Brain imaging (PET scans) shows that obese people and drug addicts have lower numbers of dopamine receptors, making them more likely to crave things that boost dopamine.
  2. Foods high in fat and sweets stimulate the release of the body’s own opioids (chemicals like morphine) in the brain.
  3. Drugs we use to block the brain’s receptors for heroin and morphine (naltrexone) also reduce the consumption and preference for sweet, high-fat foods in both normal weight and obese binge eaters.
  4. People (and rats) develop a tolerance to sugar — they need more and more of the substance to satisfy themselves — just like they do for drugs of abuse like alcohol or heroin.
  5. Obese individuals continue to eat large amounts of unhealthy foods despite severe social and personal negative consequences, just like addicts or alcoholics.
  6. Animals and humans experience “withdrawal” when suddenly cut off from sugar, just like addicts detoxifying from drugs.
  7. Just like drugs, after an initial period of “enjoyment” of the food, the user no longer consumes them to get high but to feel normal.

Exercise & the Common Cold

“The most powerful weapon someone has during cold season “is to go out on a near-daily basis, and put in at least a 30-minute brisk walk.”
Dr. David Nieman, director of the Human Performance Laboratory at Appalachian State University in North Carolina,

It’s always nice to see research that backs up something that we think is true.  In this case, researchers at Appalachian St. University have evidence that exercise is possibly the best way to avoid colds.  Read more in Regular Workouts Ward Off the Common Cold from MSNBC.  The results of this study are in line with other studies discussed in the article.

There are all sorts of products out there such as Airborne, echinacea and zinc losenges that claim to shorten or prevent colds.  The evidence on that stuff is spotty.  The evidence on exercise and its preventative powers is far more solid.  Exercise!

Rocker Shoes

An article from MSNBC, Do those funky shoes really promote fitness? discusses rocker or toning shoes, the increasingly popular shoes with a curved bottom.  The claim by these shoe manufactures (Sketchers, Reebok, MBT) is that wearers will burn more calories when they walk around in these things.

A study by the American Council on Exercise suggests that these shoes do nothing of the sort.  (Hard to believe?  A magic shoe actually doesn’t lead to weight loss??)  Participants walked all of five minutes on a treadmill while researchers monitored their heart rate, oxygen consumption and muscle usage (abdominals, butt, quadriceps, hamstrings and calves).  (I don’t know that five minutes is an adequate amount of time in these things.  Seems like participants should be monitored over the course of days or weeks).  The article goes on to discuss the possible injurious effects of wearing these weird shoes as well as a a lawsuit brought by a woman who didn’t lose any weight wearing them. On the topic of the biomechanics and rocker shoes, this article by Denver-area chiropractor and gait specialist Dr. Ivo Waerlop, goes into deep detail as to why these shoes are a bad idea.

I see these shoes as the latest fitness fad pushed on people who are hoping and praying for a fitness magic bullet.  (I love the fact that people are looking at their shoes and thinking about their calories!  How about looking at your food???)  This type of thing comes up frequently and the results of such stuff rarely lives up to the hype.  I’ll be interested to see what happens to medium- and long-term wearers of these shoes.  I think they’ll a) be disappointed in the weight they don’t lose and, b) possibly beset by chronic pain.  If nothing else, they’ll be embarrassed that they ever put on those big clunky Frankenstein clodhoppers.