Will running barefoot reduce my injury risk?

Running has become increasingly popular over the past three decades, and according to the National Sporting Goods Association there were over 40 million runners in the U.S. in 2012. Runners are also taking on longer distances, and in 2011 alone, 518,000 people in the U.S. completed a marathon. Despite advances in preventative medicine, training techniques, and prescribed footwear designs, the rate of injury continues to climb and has been estimated at 50 percent of all runners.

The consistently high injury rate among runners has led many to question the traditional model of footwear prescription to match foot morphology and even to consider whether shoes are advantageous to runners at all. The issue was brought to the forefront in 2009 with the publication of the book Born to Run by Christopher McDougall. The author outlined the running success of the Tarahumara people of Mexico, who run hundreds of miles barefoot with very little rest or injury.

Advocates of barefoot running suggest that the large, flared, cushioned heel of modern running shoes facilitates a rear-foot-first (heel-strike) running pattern. Most traditional running shoes are constructed with the heel lifted higher than the forefoot by 8-12 millimeters (or less than ½ inch), which may also facilitate a rear-foot landing pattern. Proponents of barefoot running suggest that the heel strike results in a braking force at initial foot contact and increased shock to the body. When running barefoot, you cannot rely on the cushioned and elevated heel for support and stability. As a result, most barefoot runners strike the ground first with their mid-foot or forefoot, which results in a softer landing with less braking force and less shock absorbed by the body. The mid-foot or forefoot strike is also associated with decreased stride length and increased stride frequency.

While many runners tout the benefits of running barefoot or in minimalist shoes, there are no qualitative studies that show a significant difference in injury risk among running styles or among those who wear shoes vs. those who do not. Researchers in North Carolina sought to quantify the differences in stress on the knees and ankles as well as the rate of loading through the body between rear-foot and mid-foot runners to compare the potential for injury between the two groups. In their study, entitled A Comparison of Negative Joint Work and Vertical Ground Reaction Force Loading Rates in Chi Runners and Rearfoot-Striking Runners, authors Goss and Gross examined 22 rear-foot strikers and 12 Chi runners with a mid-foot strike. Each ran on an instrumented treadmill, where a 3-D motion analysis system obtained data that included the rate of loading through the body and stress on the ankle dorsiflexors (front of shin muscles), ankle plantar flexors (calf muscles), and knee extensors (quadriceps). The results revealed that the rear-foot strikers demonstrated greater stress to the quadriceps (and knee), whereas the Chi runners demonstrated more stress to the calf muscles (and Achilles tendon). The rear-foot strike runners also demonstrated a greater rate of loading through the body at initial foot strike than the Chi runners.hich results in a softer landing with less braking force and less shock absorbed by the body. The mid-foot or forefoot strike is also associated with decreased stride length and increased stride frequency.

The take-home message from the study appears to offer helpful information for at-risk runners. If you are prone to knee injuries such as “runner’s knee” or knee osteoarthritis, there may be some advantage to shifting toward a mid-foot strike running pattern, which many achieve with a minimalist shoe. If you are prone to calf strains or Achilles injuries, you will need to exercise extreme caution when considering transitioning to a mid-foot strike pattern or minimalist shoe. It should be noted that although the mid-foot strikers demonstrated a decreased rate of loading through the body with each step, a mid-foot strike is often associated with increased step frequency, and cumulative stress may be similar. In addition, a mid-foot or forefoot strike — as is often seen in a minimalist or barefoot running shoe — may also lead to increased shock absorption through the metatarsals. This in turn may increase your risk of metatarsal stress fracture.

The bottom line? There is no optimal running style or shoe (or lack thereof) for every runner. Each runner has unique biomechanical demands and various risk factors that come into play when considering injury risk. If you are considering changing your running style or transitioning to a barefoot running shoe, it is recommended that you consult with your Physical Therapist before making the change to optimize your performance and reduce your risk of injury.

What type of running shoe works best for you? Share in the comments below.

References:

Goss, D.L., Gross, M.T., A Comparison of Negative Joint Work and Vertical Ground Reaction Force Loading Rates in Chi Runners and Rearfoot-Striking Runners. Journal of Orthopaedic & Sports Physical Therapy, 2013, Vol. 43, Issue: 10, Pages: 685-692.