Recent research has shown runners who eschew shoes may be less likely to do serious injury to their feet. However, some doctors have cautioned that the practice can cause injuries rather than prevent them. Interested to know more about the potential benefits and risks of barefoot running, I contacted Michael Fredericson, MD, who has served as the head team physician with the Stanford Sports Medicine Program since 1992. Below, Fredericson discusses shoeless running, things to keep in mind if you're thinking about doing it, and the importance of foot gear, or lack thereof, in injury prevention.
From a biomechanics perspective, does unshod running reduce the potential for injuries or joint pain?
During barefoot running the body shifts from more of a heel strike to forefoot strike. This creates a less jarring force at the moment of impact as the foot hits the ground. In addition, the motion is springier, thus dissipating the force of the foot landing over a longer period of time and slowing the rate that forces travel back up to the rest of the body (knee, hip, pelvis and spine). The implication is that shoeless runners should have less impact related injuries; however to my knowledge, there are still no solid clinical data to support this. Thus, while the jury is still out as to whether running barefoot is truly beneficial in reducing injury, there is some science to support its efficacy in dissipating stress forces to the joints of the spine and lower body.
The term "barefoot running" is often used to describe both runners that run skin to ground and those that use minimalist running shoes such as Vibram FiveFingers. From a biomechanics perspective, are both these practices the same?
I’m not aware of any significant differences between pure barefoot running and using the minimalist running shoes such as the Vibram FiveFingers. The pure barefoot running enthusiasts will tell you that even the most minimalist shoes might take away some of the feedback from the skin to the ground. In the ideal environment I recommend barefoot running, although for those who run regularly on the roads, I find it prudent to suggest having some protection over the foot. This can help prevent the obvious trauma to the skin from glass, nails, needles and other sharp trash that have a potential to cause significant harm, along with significant blistering to the skin that can occur in the initial stages.
Some doctors and runners caution that running barefoot, or in minimalist running shoes, can cause injuries such as stress fractures rather than prevent them. Are there potential health risks to barefoot running?
As mentioned above, there is some data to support that landing more on the midfoot to the forefoot can decrease impact forces. Potentially this could actually decrease the risk of stress fractures, rather than cause them. However, people that run barefoot need sound foot structure to tolerate this for longer distances. Those with severe flat feet who overpronate or those with severely high arched feet who underpronate, both do not absorb shock well and may not tolerate barefoot running, requiring some type of more supportive or cushioned shoe or even an orthotic to help dissipate the impact stresses to their foot. By running barefoot, these particular runners do potentially set themselves up for higher impact forces and stress fractures.
What should individuals consider prior to switching from traditional running shoes to barefoot running?
Runners with any problems with sensation in the feet, such as diabetics, are best advised to continue with well-padded and protective shoes. For others, if you decide to try barefoot running, proceed slowly and carefully. If you have been heel striking, you will likely have weak muscles and tendons around the foot that will need to be built up, and one should proceed with caution and avoid increasing the training load too quickly. Any abrupt change greatly increases the risk of developing tendonitis and calf muscle strain. I have seen a lot of Achilles tendon injuries among runners who were naturally rearfoot strikers, but then forced themselves to run more on the forefoot as this requires an eccentric load on the calf muscles and the Achilles tendon to keep the heel from slapping down on the ground.
I would initially start off with doing some easy strides while barefoot on the grass. We have been doing this for years with the Stanford cross-country and track team as means of building up foot strength and pliability.
When it comes to preventing injuries and running with efficient form, what are the key elements and how important are the shoes, or lack thereof, on your feet?
This is a very good question because we know that there are multiple factors that contribute to running injuries. From personal experience of taking care of the Stanford track and field team for the past 18 years and working with elite runners as a national team physician for USA track and field, I have found the majority of injured runners have deficits in their core strength that need to be addressed. Some of my research has shown that runners are also notoriously weak in their proximal hip muscles, and this strongly associates with overuse injuries of the knee and hips. We have now begun to address these strength deficits on a preventative basis for the track team and it has led to a decreased rate of injury. Additionally flexibility deficits should be addressed. Runners don’t have to be the most flexible athletes but they do need to have symmetry between their limbs. Any time there is a side-to-side deficit with an associated muscle imbalance, runners are prone to alterations in movement and gait patterns.
Finally, the one area that is most preventable is a deficit or error in a runner's training program. When someone presents with an injury we can almost always find something in the training program that may have contributed. Often times this is progressing their training volume or intensity to quickly to a level beyond, which their body can accommodate. Any change in a person's program, including transitioning to barefoot or minimalist running, should be done very slowly and over a very gradual amount of time to allow soft tissue, muscle and bone adaptations.
Previously: “Barefoot” running craze still going strong and Exploring the mysteries of the human desire to run
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