More evidence on benefits of barefoot running

Dan Lieberman recently published two new papers on running.  Here's a good Wired article summarizing the findings.  I should note that these papers aren't about barefoot running so much as forefoot and rearfoot striking, plus minimalist footwear in the first paper.

I was a data point in the first study, Effects of Footwear and Strike Type on Running Economy.  It was fun.  They hooked me up to a breathing tube to measure my oxygen usage, which took a little getting used to.  I had to run with a forefoot strike in VFFs as well as conventional sneakers, and then do the same with a rear-foot strike.  Let me tell you, it's seriously unpleasant to run with a rearfoot strike in minimal shoes.

Here are the results and conslusions:

RESULTS: After controlling for stride frequency and shoe mass, runners were 2.41% more economical in the minimal shoe condition when forefoot striking and 3.32% more economical in the minimal shoe condition when rearfoot striking (p<0.05). In contrast, forefoot and rearfoot striking did not differ significantly in cost for either minimal or standard shoe running. Arch strain was not measured in shoes condition but was significantly greater during forefoot than rearfoot striking when barefoot. Plantarflexor force output was significantly higher in forefoot than rearfoot striking, and in barefoot than shod running. Achilles tendon-triceps surae strain and knee flexion were also lower in barefoot than standard shoe running.

The second study is even more compelling: Foot Strike and Injury Rates in Endurance Runners: a retrospective study.  Lieberman has been collecting data on the Harvard cross country team for years.

RESULTS: Of the 52 runners studied, 36 (59%) primarily used a rearfoot strike and 16 (31%) primarily used a forefoot strike. Approximately 74% of runners experienced a moderate or severe injury each year, but those who habitually rearfoot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike. Traumatic injury rates were not significantly different between the two groups. A generalized linear model showed that strike type, sex, race distance, and average miles per week each correlate significantly (p<0.01) with repetitive injury rates.

CONCLUSIONS: Competitive cross country runners on a college team incur high injury rates, but runners who habitually rearfoot strike have significantly higher rates of repetitive stress injury than those who mostly forefoot strike. This study does not test the causal bases for this general difference. One hypothesis, which requires further research, is that the absence of a marked impact peak in the ground reaction force during a forefoot strike compared to a rearfoot strike may contribute to lower rates of injuries in habitual forefoot strikers.

A 2X difference in injury rates?  That's HUGE.  It's only a matter of time until all collegiate cross country programs teach their athletes how to run properly, with a forefoot strike.