How Barefoot Running Shoes May Prevent Foot Fracture

There’s strong evidence supporting the idea that a foot fracture from running may be avoided by running with a forefoot strike, not a heel strike, but to better your chances of avoiding such an injury is to run forefoot in running shoes that delivers good ground-feel clarity, shoes like barefoot running shoes (i.e shoes with a flexible, thin, level sole without any thick compressible cushioned, foam, gel or plastic materials).

In turns out that there’s a big difference in underfoot pressure stress distribution and intensity between runners who run barefoot or in barefoot running shoes vs runners who run in thickly cushioned running shoes.

Are Cushioned Running Shoes Bad for You?
Runners who wear thickly cushioned running shoes may strike the ground with greater downward and push force which taken together may produce abnormally high doses of pressure stress on areas of the foot not structurally capable of enduring such heavy pressure points. Over time, running in this way with increases in peak underfoot stress, may boil into a foot fracture as compared with running barefoot or in barefoot running shoes.

As we so well know, injury prevention efforts in running mainly target factors such as reducing impact by adding more layers of cushioning under the foot. But what’s so scientifically interesting is that many studies (references listed at the end of the article) have found the same basic conclusion: decreases in ground-feel at the feet may lead to increases in unusually high peak underfoot pressures, especially on the mid-foot. Also, the softer and thicker the underfoot cushioning in a shoe, the greater the peak underfoot pressures at the touchdown and stance phases of running, potentially putting more fracture-inducing stress on the foot.

It gets worse. Thick shoe cushioning was found to completely mask the feel of high impacts during running, leaving runners incapable of truly feeling abnormal rises in underfoot pressure and impact stress on the foot.

Evidence in alignment with this came from the pioneering work by Dr. Steven Robins, MD, who found that runners who ran in thick cushioned running shoes were exposed to more peak underfoot impact because underfoot-cushion thickness significantly diminished transmission of mechanical transients which are adequate stimuli to proprioceptors. In simple terms, when your feet are unable to feel the ground, due to thick underfoot cushioning, the failure to capture some sensory scope of the ground at the feet may be accompanied by a greater downward force and a greater push force of the feet.

What is more, thick underfoot cushioning may go against the body’s natural impact-avoidance behavioral reflex response that’s fully activated when you run barefoot or activated to a lesser degree in barefoot running shoes. In fact, a 1996 study in the journal Clinical Biomechanics discovered that running over harder underfoot surfaces with minimal underfoot protection resulted in stark reductions in peak underfoot pressure on account of the runners reflexively adjusted their landing intensity to land more lightly. 

How Barefoot Running May Prevent Foot Stress Fracture
Less protection means less impact? When you run barefoot or in barefoot running shoes, especially on harder surfaces, your initial reaction is to reflexively land with your foot that’s better positioned close to your center of mass (upper body). You also land with better forefoot strike precision. Even better, you also naturally develop a faster withdrawal retraction, or removal of the foot off the ground, too! The net effect of all this is a lighter, softer, more responsive landing strategy that reduces the braking force and you also land with less downward and push force, thereby giving you real protections against dangerous rises in underfoot pressure.
How Barefoot Running Shoes May Prevent Foot Stress Fracture
For those uninterested in barefoot running, running in minimalist shoes, like the Altra Escalantes may help you avoid a bony fracture of the foot because these shoes are specifically configured to improve your stride control and forefoot strike positioning at touchdown during running. Also, the flatness and thinness of most minimalist running shoes produces enough underfoot sensory stimulation cueing the foot to land more lightly, with less downward force which helps drive down underfoot pressures.

Underfoot ground-feedback can really help you reign in your worst mechanical impulses, like pounding the pavement and landing heel-first, but what enables the body to make such important mechanical adjustments in the absence of underfoot-cushioning?

Its ALL About Proprioception!

When you can feel the ground more fully with your feet, you have better proprioception. Proprioception is defined as the constant feedback loop within your nervous system that informs your brain about what position you are in and what forces are acting upon your body at any given point in time. The body’s proprioceptive system also plays an important role in maintaining the body’s natural mechanical defenses against high impacts, which is proven to be optimized barefoot.

How exactly do our feet importantly contribute to proprioception?

How Barefoot Running May Prevent Foot Stress Fracture

The underfoot is incredibly densely populated with groups of nerves that belong to the proprioceptive system whereby when you are barefoot, there’s more rich sensory information that converges through the bottom of the bare foot that is sent more quickly to the central nervous system (spinal cord and brain) as compared with conventional running shoes. From here, a range of nerves, especially in the joints, are switched on more fully which directly activates a range of muscle and reflexive responses that are key organizers of more functional movement patterns and other biomechanical outputs that help produce impact-avoidance behaviors in the absence of underfoot cushioning. This is precisely the reason you don’t end up with high impacts crashing into the foot or leg when you run barefoot, regardless of surface hardness, and is why increased barefoot running training fits so nicely into the role of injury prevention and form correction.

But when the proprioceptive system is blocked at the feet with thick shoe cushioning, the proprioceptive feedback loop may become compromised in ways that may encourage more force intensive, unbalanced footfalls as well as abnormal foot postures which in turn may project greater stress and strain on the foot as compared with running barefoot or in barefoot running shoes. In essence, instead of adding protection, thickly cushioned running shoes seems to take the protection away. Likewise, if cushioned running shoes can’t reduce all the impact, how can they prevent all injuries?

Are Cushioned Running Shoes Bad for You?

Obviously, there are countless variables involved, and many more to be discovered, that cause running-related injuries, but certain running shoes, namely thick cushioned running shoes are on record for disrupting underfoot proprioception, resulting in a more heavy footstrike intensity with greater impact production of which injury troubles tend to begin.

This is why you can do better with your injury prevention efforts by integrating barefoot running in your regiment as barefoot running is most effective to tap into the proprioceptive power that’ll assist you in developing a landing strategy that’s so brief that certain impact variables are not fully produced on the foot and leg.

To help you get off to a good start on barefoot running, here’s an easy barefoot running training guide that’s sensibly incremental so you don’t overdo it!

References:

Chen et al. Influence of sensory input on plantar pressure distribution. Clin Biomech, 1995; 10(5):271-74.

Hennig EM., Valiant GA and Liu Q. Biomechanical variables and perception of cushioning for running in various types of footwear. J Appl Biomech, 1996; 12(2):143-150.

Pell RFt, Khanuja HS, Cooley GR. Leg pain in the running athlete. J Am Acad Orthop Surg. 2004;12:396-404.

Robbins et al.  Sensory attenuation induced by modern athletic footwear. J of Test and Reg,  July 1988.

Sharma J, Golby J, Greeves J, Spears IR. Biomechanical and lifestyle risk factors for medial tibia stress syndrome in army recruits: a prospective study. Gait Posture. 2011;33:361-365.


P.S. Don’t forget to check out my Run Forefoot Facebook page here! It’s a terrific place to ask questions about forefoot running, barefoot running and injury. I’m always happy to help!

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If you’ve enjoyed by blog’s content about barefoot running, you’ll LOVE my content over at my YouTube channel, here, where I discuss at great lengths the health and performance benefits of barefoot running as well as forefoot running vs heel strike running.

Bretta Riches

"I believe the forefoot strike is the engine of endurance running..."

BSc Neurobiology; MSc Biomechanics candidate, ultra minimalist runner & founder of RunForefoot. I was a heel striker, always injured. I was inspired by the great Tirunesh Dibaba to try forefoot running. Now, I'm injury free. This is why I launched Run Forefoot, to advocate the health & performance benefits of forefoot running and to raise awareness on the dangers of heel striking, because the world needs to know.
Bretta Riches

P.S. Don't forget to check out the Run Forefoot Facebook Page, it's a terrific place to ask questions about forefoot running, barefoot running and injury. I'm always happy to help!