The popularity of minimalist running has grown immensely over the last few years. Runners are now spending millions of dollars on thin soled shoes that mimic the natural anatomy of the feet. Proponents of “natural running” claim that training in bare feet or thinly soled shoes is the most effective and safest way to run. Unfortunately, a recent study in Utah published in the Medicine & Science in Sports & Exercise throws this claim into question.

The Vibram Five Fingers Study

Findings from the recent scientific study (which you can find here) reveal that running barefoot or with thin rubber shoes increases the chances of foot bone injuries.

In a 10-week study on the effects of Vibram Five Fingers shoes on runners, Utah based researchers divided a team of amateur runners into 2 groups. The first one was asked to continue running with their traditional running shoes while the second group was asked to slowly transition from typical athletic shoes to Vibram Five Fingers following a careful period of retraining.

During the course of the research, the Five Fingers contingent were required to follow the Vibram recommended transition plan. This involved running a single day of 1-2 miles in thin soles the 1st week, and was followed by adding an extra day of Vibram running over the next 2 weeks (for a total of 3 days of 1-2 mile runs in the thin shoes by the end of the 3rd week). After that period, the group was asked to boost their daily mileage as it felt comfortable to them.

After the allotted 10-week period, both groups were subjected to MRI scanning with the results compared to the scans taken before starting the trial. Those who stuck with their traditional running shoes showed no change in foot stress, while those who made the thin sole transition had a dramatic increase in bone marrow edema (a sign of bone injury and the body’s response to increased stress).

MRI Results

The results clearly showed that half the Five Fingers runners had sustained some form of foot injury, and that 2 additional runners had developed full stress fractures in the toes and heel.

What the Study Tells Us

The conclusion to this 2 month long research tells us that minimalist running should only be attempted with a very slow transition period, if at all.

Running with Vibram Five Fingers or other similar shoes significantly alters the biomechanics of our foot with each strike. Instead of hitting the ground with the heel, minimalist running places the stress on the forefoot and mid foot area, a sensitive region where the tiny metatarsal bones reside. As such, thin running shoes are likely to trigger fractures on the metatarsals, calcaneal bones and place extra stress on the Achilles tendon.

While the merits of running with thin soled shoes will continue to be debated, it is safe to say that the switch to minimalist running requires a gradual transition to avoid injuring the foot.