Running with flat feet may increase the risk of abnormal, damaging movement patterns of the foot (also known as over-pronation) during running which may create mechanical chaos at the ankle, knee and hip-joints. Why do flat feet, excessive pronation and increased injury-risk during running all get linked together?
Generally, flat feet indicates poor overall foot strength and health. Specifically, if the muscles and soft tissue groups that line the arch become weak, they cannot sufficiently uphold the arch, and the arches eventually fall into a collapsed state. Even worse, weak foot muscles lose their grip on suspending pronation within a safe, tolerable range. Out of this may trigger abnormal foot motions (over-pronation) during the stance phase of running, which may lead to tissue and muscular over-strain of the foot-ankle complex, and therefore a hotbed for injury.
How do the feet, especially the arches, become this fragile and mechanically incompetent?
Long-term use of cushioned, stiff, overly protective footwear locks the feet into a tightly constrained state that significantly shuts down much of the muscular engagement necessary to keep the feet functionally strong.
Bottom line, running with weak feet is not a way to get you out of injury! To give you a good idea of how quickly foot health deteriorates in running shoes with excessive cushion and support, a 2013 study in the journal Foot and Ankle Research found that runners who wore running shoes with arch support showed reduced arch height right after a prolonged run, suggesting that the strength-robbing effects of stability running shoes are alarmingly fast-acting!
The researchers underscored that poor foot strength may prompt frequent changes in arch height profile upon weight-bearing activities, like running, and may result in poor weight-bearing responses of the foot. In other words, when the feet are weak, the harder it is for the foot’s arch to be upheld, the more easily strained and likely the feet are to injure under normal loading conditions.
The researchers also cautioned that weak foot muscles may cause the anti-pronatory muscles in the foot to become increasingly unstable and unreliable at delivering corrective pronatory support. This contributes a greater extent to over-pronated feet that become more vulnerable to fatigue and pain during long distance runs. This data fits into a continuum of complementary findings showing that weak, low arched feet increases forefoot abduction (forefoot shifts away from the mid-line, while the heel dramatically bends inward) during the stance phase of running. This mechanical entanglement causes greater torque and strain to ripple out from the foot, up the leg during running. The researchers noted that all this frontal assault on the foot as well as the lower and knee, which partly stems from the change from high to low arch height, adds up over time and may result in an outsized risk of bone, joint and soft tissue damages, if running were to continue.
From this, its easy to understand how supportive, cushy running shoes may actually disadvantage a runner’s injury prevention efforts, which is something not often heard in Runners World. But, after the barefoot running movement boom, strengthening the feet by wearing less on them is quickly gaining acceptance and appraisal by many. In fact, many habitually shod (shoe) runners who switched to minimalist running and/or barefoot running have showed strikingly similar improvements in not only running form, but in foot functional health.
Less Support is the BEST Flat-Foot Support!
According to the researchers, much of the soft tissue groups in the feet act as motion stabilizers of the foot-ankle complex. Strengthening and conditioning these tissue groups would depress abnormal foot motions. The best way to strengthen these sectors of the foot is to keep them active.
By now, it should be obvious that to give your feet the best start at boosting arch height and functional strength in a sustainable way is to avoid wearing motion control stability cushioned running shoes, and instead, aim for wearing minimalist running shoes which are shoes that aren’t filled with structural support elements, permitting the foot to move in its natural motion more fully and are sculpted to accommodate to any unique foot structure. This is how minimalist shoes keep the feet going in a engaging state for the benefit of undoing the damage caused by modern footwear.
As I just briefly touched on, foot strike pattern when running may also have a big role to play in influencing arch function and height. Because of the particularly way the arch engages with the ground at touchdown in a forefoot strike landing, may grow the arch stronger every time you land forefooted, not rearfoot (heel strike) during running.
All in all, there’s no reason for runners, or anybody for that matter, to have weak, painful, flat feet. Getting your feet to work independently via barefooting or minimalist shoes is a big part of the sustainable solution, but not the entire solution. One of the greatest outcomes in adopting the forefoot running style is it may really finish the job in preventing a loss in arch height by engaging the feet in a mechanically competent manner critical to healthy functioning arches.
Cowely E and Marsden J.The effects of prolonged running on foot posture: a repeated measures study of half-marathon runners using the foot posture index and navicular height. J Foot Ankle Res, 2013; 6(20):2-6.
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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.