Cushioned shoes aren't good for your feet

More and more research points to a serious mistake we made in how biomechanics works.

  • A new study from Helsinki found that the more you cushion your feet, the more likely you'll get injured.
  • This follows previous studies showing that cushioned shoes leave you more susceptible to pain and injury.
  • A few million years of evolutionary design has been usurped by shoe marketing campaigns.

A lot happened to our feet in the transition from being quadrupeds to exclusively bipedal. While the upright organization of our limbs and organs resulted in many benefits in our communication skills and ability to breathe, for example, it greatly decreased the strength and flexibility of our feet, which once needed bendable toes that could grasp tree branches and a healthy dose of keratin, the protein that forms calluses, which protected us from sharp objects on the ground.

For most of the millions of years we've been evolving we didn't wear shoes; during the 45,000 years we've been wearing some form of footwear they've been minimal. More aesthetically complex (and biomechanically questionable) fashion-forward shoes and sandals are a few thousand years old, though finding a society that championed elaborate footwear took time. The decision to confine our feet in tighter spaces higher up off the ground was one of status, not anatomy—only"savages" didn't properly protect and adorn their feet.

It's been a decade since the (slightly) controversial Born to Run was published, and so it's been a decade that the minimalist versus cushioned shoe debate has been raging. (The argument for both has existed far longer, but that book brought it to the forefront of the growing running community's consciousness.) When Vibram was sued for making false health claims, cushioned shoes advocates rejoiced, even if the lawsuit focused on to inflated claims, not the utility of going "barefoot."

Besides, citizens of economically-advanced societies are not going to go full barefoot. While our feet would likely grow calluses as they (painfully) became accustomed to hard surfaces, what really matters to runners is impact peak. When walking, this force is equal to your body's weight, but when running that forces triples in weight. Despite constant debate about best running form, some people naturally heel strike, which is easier on your calf muscles and Achilles tendon and allows you to lengthen your stride more easily. When walking, we mostly heel strike first.

But as Christopher McDougall wrote in Born to Run, running is more like jumping than walking. Right now if you jump while barefoot, you're going to land on your forefeet. Cushioned shoes won't allow you to forefoot strike naturally; they also cushion the impact peak so that you don't feel the weight of each strike. While running shoe companies have marketed this as a bonus, Daniel Lieberman points out the downsides:

Runners who generate higher, more rapid impact peaks are significantly more likely to accumulate repetitive stress injuries in their feet, shins, knees, and lower back.

Research he conducted on the Harvard cross country team discovered that heel strikers were twice as likely to be injured than forefoot strikers. Minimalist footwear decreases the likelihood you'll heel strike, thus decreasing the risk of injury.

Now a new study published in Scientific Reports backs this up—sort of. The Helsinki-based team points out that while seemingly advanced technologies in cushioned shoes keep appearing, rates of injuries do not. Their study notes what Lieberman discovered years ago: the more you pad your feet, the more intense the impact peak, thus the higher the injury rate:

We found that highly cushioned maximalist shoes alter spring-like running mechanics and amplify rather than attenuate impact loading… We attribute the greater impact loading with the maximalist shoes to stiffer leg during landing compared to that of running with the conventional shoes. These discoveries may explain why shoes with more cushioning do not protect against impact-related running injuries.

This small study of twelve men (average age: 27) compared conventional-cushioned shoes with maximally-cushioned shoes, so it's impossible to use it in making an argument for minimalism. That said, if you consider that impact peak will be reduced with less cushioning, we can extrapolate to confirm what Lieberman (and others) have advocated: the more you swaddle your feet in what biomechanist Katy Bowman calls "foot coffins," the more likely you're going to injure yourself.

Feet are amazingly complex structures. We often forget that—until they hurt, which happens more often in modern societies. Each foot has 26 bones and 33 joints that connect over 100 muscles, ligaments, and tendons. Everything we do depends on the health of our feet, yet every day most people slide them into small, padded spaces with little room for movement, and we haven't even touched the ankle joint yet. But Bowman does:

The ideal footwear is "none" for any human. A shoe will weaken the function of the musculature within the foot (intrinsic) by limiting the motion to the ankle.

Arch support atrophies the muscles up the chain dependent on strong arches; lack of ankle flexility has system-wide effects. Instead of strengthening those muscles, most responses to problems like plantar fasciitis—a condition I see often in my role as fitness instructor—are to continually baby the feet. Fascia needs lubrication to work effectively. Further padding the feet in an attempt to reduce inflammation is the exact opposite path to successful healing, but by the time you've acquired this particular ailment, the harder it's going to be to move without pain, creating a tragic feedback loop that severely restricts movement.

What seems like progress is often regressive, especially when we choose aesthetics over form. Squatting, for example, is the means by which our bodies were designed to defecate. Toilets were a societal advancement that was (and still is in many countries) indicative of class, yet the ninety-degree angle of that seated arrangement does more harm than good to our ability to "go."

So it is with cushioned shoes. Given the bacterial playground that is the ground, going completely barefoot is not in our best interests. But common sense is. Millions of years of evolving design do not surrender their anatomical wisdom without severe consequences.

--

Stay in touch with Derek on Twitter and Facebook.

3D printing might save your life one day. It's transforming medicine and health care.

What can 3D printing do for medicine? The "sky is the limit," says Northwell Health researcher Dr. Todd Goldstein.

Northwell Health
Sponsored by Northwell Health
  • Medical professionals are currently using 3D printers to create prosthetics and patient-specific organ models that doctors can use to prepare for surgery.
  • Eventually, scientists hope to print patient-specific organs that can be transplanted safely into the human body.
  • Northwell Health, New York State's largest health care provider, is pioneering 3D printing in medicine in three key ways.
Keep reading Show less

Where do atoms come from? Billions of years of cosmic fireworks.

The periodic table was a lot simpler at the beginning of the universe.

10 excerpts from Marcus Aurelius' 'Meditations' to unlock your inner Stoic

Great ideas in philosophy often come in dense packages. Then there is where the work of Marcus Aurelius.

(Getty Images)
Personal Growth
  • Meditations is a collection of the philosophical ideas of the Roman Emperor Marcus Aurelius.
  • Written as a series of notes to himself, the book is much more readable than the dry philosophy most people are used to.
  • The advice he gave to himself 2,000 years ago is increasingly applicable in our hectic, stressed-out lives.
Keep reading Show less

An organism found in dirt may lead to an anxiety vaccine, say scientists

Can dirt help us fight off stress? Groundbreaking new research shows how.

University of Colorado Boulder
Surprising Science
  • New research identifies a bacterium that helps block anxiety.
  • Scientists say this can lead to drugs for first responders and soldiers, preventing PTSD and other mental issues.
  • The finding builds on the hygiene hypothesis, first proposed in 1989.

Are modern societies trying too hard to be clean, at the detriment to public health? Scientists discovered that a microorganism living in dirt can actually be good for us, potentially helping the body to fight off stress. Harnessing its powers can lead to a "stress vaccine".

Researchers at the University of Colorado Boulder found that the fatty 10(Z)-hexadecenoic acid from the soil-residing bacterium Mycobacterium vaccae aids immune cells in blocking pathways that increase inflammation and the ability to combat stress.

The study's senior author and Integrative Physiology Professor Christopher Lowry described this fat as "one of the main ingredients" in the "special sauce" that causes the beneficial effects of the bacterium.

The finding goes hand in hand with the "hygiene hypothesis," initially proposed in 1989 by the British scientist David Strachan. He maintained that our generally sterile modern world prevents children from being exposed to certain microorganisms, resulting in compromised immune systems and greater incidences of asthma and allergies.

Contemporary research fine-tuned the hypothesis, finding that not interacting with so-called "old friends" or helpful microbes in the soil and the environment, rather than the ones that cause illnesses, is what's detrimental. In particular, our mental health could be at stake.

"The idea is that as humans have moved away from farms and an agricultural or hunter-gatherer existence into cities, we have lost contact with organisms that served to regulate our immune system and suppress inappropriate inflammation," explained Lowry. "That has put us at higher risk for inflammatory disease and stress-related psychiatric disorders."

University of Colorado Boulder

Christopher Lowry

This is not the first study on the subject from Lowry, who published previous work showing the connection between being exposed to healthy bacteria and mental health. He found that being raised with animals and dust in a rural environment helps children develop more stress-proof immune systems. Such kids were also likely to be less at risk for mental illnesses than people living in the city without pets.

Lowry's other work also pointed out that the soil-based bacterium Mycobacterium vaccae acts like an antidepressant when injected into rodents. It alters their behavior and has lasting anti-inflammatory effects on the brain, according to the press release from the University of Colorado Boulder. Prolonged inflammation can lead to such stress-related disorders as PTSD.

The new study from Lowry and his team identified why that worked by pinpointing the specific fatty acid responsible. They showed that when the 10(Z)-hexadecenoic acid gets into cells, it works like a lock, attaching itself to the peroxisome proliferator-activated receptor (PPAR). This allows it to block a number of key pathways responsible for inflammation. Pre-treating the cells with the acid (or lipid) made them withstand inflammation better.

Lowry thinks this understanding can lead to creating a "stress vaccine" that can be given to people in high-stress jobs, like first responders or soldiers. The vaccine can prevent the psychological effects of stress.

What's more, this friendly bacterium is not the only potentially helpful organism we can find in soil.

"This is just one strain of one species of one type of bacterium that is found in the soil but there are millions of other strains in soils," said Lowry. "We are just beginning to see the tip of the iceberg in terms of identifying the mechanisms through which they have evolved to keep us healthy. It should inspire awe in all of us."

Check out the study published in the journal Psychopharmacology.