Run for Your Life

by Mark Cucuzzella

  The foot pronates, rolling from the outward edge inward, toward the big toe—dispersing impact in a sideways (inward) direction.

  The toes splay outward, adding balance and forward propulsion. The toes then dorsiflex (bend upward) and stabilize the foot for toe-off.

  All of these motions—downward, to the side, and forward and back—dissipate the forces of impact at the same time that they create a wide, stable platform for the foot. Then, when the foot leaves the ground, the bending toes straighten to reset the plantar fascia and the transverse arch. The foot is cocked and ready for the next impact. Let’s explore this.

  THE ARCH AND THE WINDLASS

  In engineering terms, the foot works like a windlass mechanism, in which the movement of one part transfers energy to another part, while initiating other compensatory movements. (Think of jetliner wheel assemblies, which are designed to trigger a cascading series of changes to the plane’s behavior the moment the wheels touch the tarmac.) In the case of our foot, this complex ground contact response works with surprising efficiency.

  At the moment when weight bears onto the forward leg, the foot is soft and flexible and acts as a shock absorber. Then the main, longitudinal arch flattens, stretching and “loading” the plantar fascia with stored energy, like a spring. (Place one foot lightly on the floor. Now place all your weight on it, and note how your toes move forward. This is your foot momentarily lengthening as the plantar fascia stretches and flattens.)

  At the end of the running stride, this springlike energy is released like a slingshot, efficiently propelling you forward.

  Try this: Reach down and pull your big toe upward. Watch the arch of your foot rise. You’ll see this even if you have been told you have “flat feet.”

  Picture the arch as a triangle. The plantar fascia ligament is at the bottom, and acts like a springy high-tension cable. At the completion of the stride, when the toes are bent upward, the plantar fascia shortens and tightens as it wraps beneath the metatarsal bones, elevating the arch.

  PRONATION

  Impact forces are also dispersed by pronation—the natural motion of the arch flattening as the foot rolls inward. This is best seen when running or landing from a jump, when the foot first contacts the ground on the outside edge, with the ankles tilted slightly outward. As the body weight settles onto the foot, the ankles roll inward and the foot flattens out.

  Pronation: the natural rolling from outward to inward.

  Pronation dissipates a significant amount of shock. For this reason, despite its bad rap from the running shoe industry, it may be the most essential of all foot functions. Pronation can’t occur naturally with arch supports or posted shoes. Many modern shoes, intending to protect us, block the foot from rolling inward. The impact forces are then relayed farther up the body into other structures that weren’t designed to absorb the full impact.

  TRANSVERSE ARCH FLATTENING

  The ball of the foot is where five very mobile metatarsal bones are located. They are arrayed in an arch known as the transverse arch.

  The second metatarsal acts as the keystone of the transverse arch.

  With each step, the foot first connects with the ground on the outside, making for a soft touchdown for the landing foot. As body weight loads onto the foot, the transverse arch flattens like the springs in a suspension system. This widens the forward part of the foot, at the ball, by about 15 percent. This dynamic widening is rarely accounted for when shoes are being fitted, and is why you do not want a “snug fit.”

  EVEN THE TOES COME INTO (S)PLAY

  As the five metatarsals flatten and widen on toe-off, the five toes want to splay even farther apart than the metatarsals, and reveal an open space between each toe. At this point, the lowly toes play a vital role by (a) forming a stable, wide base of support, (b) giving feedback on the condition of the terrain in the form of sensory proprioception, (c) helping disperse the energy of impact, and (d) resetting the arch by tensioning the plantar fascia.

  Correct alignment of the big toe (stable foot). Note the position of the sesamoids indicated by the fingers.

  Alignment of the big toe with hallux valgus (unstable foot). Note the shift of the sesamoids.

  Normally the toes are the widest part of the foot. Unfortunately, since shoe design is dictated by fashion rather than by foot biomechanics, we mainly see shoes with tapered toe boxes. When the big toe—the captain of the ship—is not aligned, you are left with a foot that is unstable, is incapable of fully absorbing shock, and has limited propulsive properties. If you stand up and balance on one foot, you’ll quickly understand the big toe’s important stabilizing function. Can you feel it fully activated, gripping the ground?

  I have a condition that is shared by millions of men and women called hallux valgus, a deformation of the big toe into a bent-inward position. This is typically caused by perpetually cramming our feet into the pointed toe boxes of most shoes (as I did when I was younger), and it is difficult to correct surgically. A product called Correct Toes can help by splaying and securing the toes in their normal anatomic position.

  Twenty years ago, along with my hallux valgus, I suffered severe arthritis in my big toes. Surgery helped somewhat, but the Correct Toes almost immediately improved my balance and my stride efficiency. My feet again became magic springs, just as when I was a child running effortlessly on the beach. (I still wear the Correct Toes when I run, either in sandals or inside my shoes, as this condition has been difficult to fully correct.)

  My foot. Note the inward angle of the large toe.

  My foot with Correct Toes. Note that the big toe is properly aligned, in a straight line with the foot.

  To see how this works, try the following:

  Place your feet squarely under your hips, and flare your toes as wide as you can. Think of the lunar lander.

  Hop as gently as you can, as if jumping rope, while maintaining a wide, stable foot position.

  Now squeeze your toes together and rotate your feet inward until they are in an overpronated position. Repeat the simple hops. Compare this more jarring thud to the earlier boing, boing, boing sensation.

  Weak, flattened feet (left) versus strong, springy feet (right). Note the effect on the alignment of the knees.

  I share this digression on biomechanics with you for a simple reason: the toes and plantar fascia ligament must be able to move freely, without restriction, for proper shock absorption and propulsion. In its natural state (without shoes), the foot moves efficiently and safely. It rolls, stretches, expands, and grasps the ground. The role of a shoe should be to complement, and in some cases try to restore or re-create, normal foot function, while protecting us from the surface of the ground.

  I frequently see adults in my store or medical clinic who are convinced they can no longer run. This is because they have allowed the natural springs in their feet and legs to be decommissioned, in effect, by improper footwear and by lack of use. When the natural springs of our feet are rendered ineffective, the joints end up taking the load. That load—the impact forces of running and walking, and the pain along with it—just gets shifted up the kinetic chain to our knees, hips, and spine. It’s distressing to see this when we consider that the surface areas where each foot’s thirty-three joints meet are large enough to dissipate the forces generated by a full lifetime of normal, unrestricted walking and running.

  At least half of those who run suffer a running-related injury each year. In the U.S. military, lower-extremity-overuse injuries are a leading cause of lost days of duty—at a high cost to the taxpayer and to individual careers. This should not be the case.

  SHOELESS BUT NOT CLUELESS

  So, do we really need shoes? They do help us to endure extreme temperatures and to negotiate urban and off-road environments. But their precise function
is still being debated.

  Heavily cushioned footwear with arch supports, stability control, and elevated heels was introduced in the 1970s and became the norm in the 1980s. Gradually, shoe companies made them bigger and bulkier and snazzier—all to impart an illusion that they could improve performance and reduce injury. Common sense suggests that these contrivances would reduce impact between the (impossibly hard, unforgiving) pavement and our (delicate, injury-prone) feet.

  Unfortunately, it has not worked out this way. Forty years later, there is no clinical or scientific evidence that cushioned, supportive shoes protect our feet and kinetic chain from injury.

  How could this be?

  It may be that the role of the shoe has been misunderstood. The modern, comfortable, cushioned shoe was designed as a solution to a problem that was never clearly defined. It was intended to compensate for perceived weaknesses and hazards. In one sense, these shoes have eased the burden on our feet so that they need to work less. But our feet are designed to work hard. In doing work, they gain strength. Our ancestors did not have golf courses.

  A shoe’s most important function should be to protect our soles, the same way that work gloves protect our hands. Beyond that, they should allow our feet to behave like feet, with freedom and flexibility, so that the muscles can rebuild strength and natural springiness. Along the way, they will be better protected from injury.

  In particular, elevated heels—a feature of most modern footwear, including running shoes—shift the center of mass forward and away from the critical site in the foot that is meant to bear load (the sustentaculum tali, for medical folks). When the heel is elevated, the arch is destabilized, and the fifth metatarsal (another key stability structure) is lifted off the ground. This causes a domino effect of compensations. Abnormal forces are generated in our knees, hips, and lower back, as we alter our natural standing, walking, and running posture.

  Make a short stack of wooden building blocks. Now slightly elevate one edge of the block at the bottom of the stack. To restabilize the stack, you’ll need to slightly adjust the position of every block. Picture how this is routinely being done to your feet, knees, hips, and spine. (I’ll readily grant that if you have a bit of heel elevation and are running pain free, I wouldn’t insist you should change shoes.)

  UNEXPECTED CONSEQUENCES

  Shoes with motion-control features, which restrict pronation, are potentially injurious. One study found that U.S. military trainees may have suffered higher injury rates in shoes that were prescribed specifically for their perceived foot types. In particular, “rocker toes” don’t allow the toes to fully dorsiflex, and they inhibit the arch from fully resetting itself at the end of the stride. If you combine this with an elevated heel and a narrow toe box, your muscles, tendons, and ligaments will shorten and weaken over time, and your default posture will change.

  The 2016 JFK 50 Mile run, in Shamma Sandals and Correct Toes

  Soft cushioning of the heels and soles presents another problem, by encouraging a long, bounding stride, accompanied by heel striking. In a thinner, less cushioned shoe, overstriding is uncomfortable, and you naturally avoid doing it. Thinner shoes also offer more proprioception, or sensory feel for the ground. If you can sense the terrain beneath you, the muscles in your feet and core fire more quickly and decisively, helping to stabilize you and improve running efficiency, while building strength in your feet. We will discuss overstriding in chapter 8, on mobility.

  When I was first injured in high school track, I was told to run in supportive shoes. And when I was reinjured, I was advised to run in supportive shoes with an orthotic. I did this for years, until I started to notice something: my legs’ elastic springs weren’t being called on to perform. They grew weaker and less resilient. As my athletic bag filled with orthotics and other shoe accessories, my condition worsened as my spring dampened. Five years of chronic plantar fasciitis (and debilitating large-toe pain) later, in the year 2000, I finally had surgery.

  Surgery helped, but not as much as better running form and less substantial shoes. I started by cutting off the heels of my cushioned shoes, and removed the inserts. I have since completed more than fifty marathons (and multiple ultra-marathons) in such minimalist shoes.

  SO, WHAT’S THE BEST SHOE?

  In the running world, the subject of shoe design has become divisive and political, with an abundance of claims and counterclaims, all supported by sketchy science. We need to hurdle over the shoe and running rhetoric and ask what kinds of shoes enhance the natural biomechanics of the foot and protect and strengthen the kinetic chain. A shoe should complement nature, not try to outsmart it.

  The array of athletic footwear for sale is bewildering. Fortunately, there are now many brands and styles of shoe that simply let our feet be feet. No single shoe is perfect for everyone, and no single shoe may be perfect even for one person. But through a few simple assessments, readers should be able to make an educated choice of what can work best for their bodies relative to their running environments. Each of us is an experiment of one, and we should expect some trial and error in the shoe selection process.

  There are some basic elements of shoe design, however, that work to enhance natural foot function:

  A flexible sole. The shoe should bend easily and allow the foot to flex and expand and contract naturally. (The more flexible the sole, the stronger your foot needs to be, too.)

  A lower “drop”—or no drop—in elevation from heel to toe. This is the difference in height between the heel and the forefoot, and can be thought of as the slope or grade. Modern shoes typically have a 6 to 10 percent grade, and we know what that means on the highway: caution! If the shoes you are accustomed to wearing (whether athletic or street shoes) have elevated heels, reduce the height of the heels, especially for standing and walking. Information on drop, in millimeters, is available for many athletic shoes.

  A thinner shoe. If your running shoes have thick, soft soles, look for a shoe that allows you to feel more of the ground (which will help train you away from overstriding). It takes more energy to walk or run on a soft surface—think sandy beach. You want a firm surface to act as a platform to set your stride. Thinner shoes are also lighter, a huge bonus for overall comfort and efficiency.

  Select shoes based on fit, not size. You need plenty of room for your toes to splay and your feet to stretch as they move. When sized properly, you may end up in a shoe a full size or two larger than what you had before.

  TRANSITIONING TO MINIMALIST

  Moving to lower-drop or minimalist footwear should be a process, not an event. The muscles, tendons, and ligaments in your feet and legs need time to lengthen and strengthen. While adapting a little soreness is inevitable but you should not be in pain.

  Few people can run in ultra-minimalist Vibram FiveFingers right away, but you can start walking and playing in a minimalist shoe immediately. Walking is the perfect transition. Or try “transition shoes”—an intermediate pair (or two) that gradually introduce you to the features just listed. Such transition shoes typically have 4 to 6 millimeters of drop (elevation loss from heel to toe), versus the standard 12 to 14 millimeters of drop in most running shoes.

  Gradually reduce your support, and rediscover spring in your step.

  Progression can take months to years.

  Begin by going barefoot as much as possible—at home, for instance—and wear your minimalist shoes for work and for walking, as these activities involve less impact. Mix it up!

  When you begin to master the art of slow, comfortable jogging, with a short, rhythmic stride and quicker cadence, you’ll be using muscles and tendons the way they were designed. Your feet will tend to land less on the heel—which is good, because heel landings slow you down like a brake, and deliver jarring forces. You’ll naturally land more on the midfoot. Count on three to twelve months to rebuild the strength and
flexibility that modern shoe designs have taken away from you. It may take five years to build up to running a marathon in sandals.

  There’s a bonus to wearing lighter footwear, too. British researchers measured higher oxygen consumption (energy expenditure) by runners wearing shoes, compared to running in bare feet. They attribute this to the additional energy needed to carry the mass of the modern shoe. (The effect of any weight on the lower legs is magnified when compared to carrying the same weight closer to the core.)

  Most runners find little long-term help from podiatrists and other medical specialists, and instead seek advice and share experiences at their local running hangout. My store, Two Rivers Treads in Ranson, West Virginia, has become a running and footwear clinic—an informal laboratory for assessing and understanding runners’ problems. We make a point of offering only advice and education that is evidence-based and truly useful. The process has been fascinating: the customers, and the runners in the local races, have taught me more than I have taught them.

  IT’S NOT ONLY ABOUT THE FEET

  If I sound like an advocate trying to steer you away from the mainstream, then believe me: if you are already running joyously, without pain, stick with what you have. Even if you are not injured, however, you may want to move to a more minimalist shoe and see how your feet and your body respond. You might be surprised.