Adopting the correct foot-to-ground strike style can help runners who suffer from chronic running injuries who are using
barefoot-style shoes avoid additional risks. These are the findings of new research on Vibram FiveFingers, a sock-style shoe that
simulates the effect of running barefoot while protecting the foot.
The American Council on Exercise (ACE), is the largest nonprofit fitness certification, education and training organization in the world and also America's leading authority on fitness. They announced the result of the research, by the University of Wisconsin, La Crosse, Exercise and Health Program, and led by Dr John Porcari, and Caitlin McCarthy, in a statement at the end of September.
The research is not published in a peer-reviewed journal, but you can download a copy of the report from the ACE website.
ACE's Chief Science Officer, Dr Cedric X. Bryant, said:
"We've seen an increasing number of individuals using barefoot-style running shoes, and felt it critical to examine this trend."
"The bottom line is that runners must first and foremost modify their running style for ultimate safety and benefit, and this should be done gradually through regular practice. Once that is achieved, Vibram FiveFingers can be a safe and effective shoe for those who want to experience the feel of barefoot running," he explained.
Promoters of barefoot running say it is safer because it reduces the risk of injury compared to running in traditional shoes. They say this is because running shoes encourage runners to strike with their heels first, which causes more pounding and stress.
Running barefoot, conversely, encourages the foot to land near the ball, resulting in less pounding and less risk of injury. Vibram say their product helps runners achieve the safer forefoot-strike of barefoot running while avoiding the abrasion on the soles.
ACE asked the researchers to look into what happens when runners switch from traditional running shoes to minimalist shoes like Vibram FiveFingers, which they describe on their website as "a quirky-looking sock-style shoe with separate compartments for each toe".
For the study, the researchers recruited 16 healthy, injury-free, female "recreational joggers", aged from 19 to 25.
Before the evaluation, each jogger was fitted with a pair of Vibram FiveFingers Bikila which are designed for running.
For two weeks before the test, to get used to their new shoes, the volunteers wore them when they went out running, for 20 minutes at a time, three times a week.
After this two-week acclimatization, the researchers carried out lab evaluations of the volunteers' running style as they were invited to run on a on a 20m runway under three different conditions: (1) wearing the Vibrams; (2) wearing a pair of traditional running shoes; and running truly barefoot.
The researchers evaluated a 3-D motion analysis and took measures of ground-reaction forces as the runners completed seven trials for each of the three conditions. The order of the trials for the Vibrams and the running shoes was random, but the barefoot trial was always measured last.
The results showed that:
- All the runners were rear-foot strikers when they ran in traditional shoes.
- Half of them switched to fore-foot strike when they ran in Vibrams or barefoot.
- The other half kept to the same rear-foot strike style through all of the conditions.
- Those who switched to fore-foot style, showed greater "plantar flexion" (pointing the foot away from the leg, as when you step on the gas pedal), which seemed to allow better absorption of the forces of impact.
- Those who continued with rear-strike style when running in Vibrams or barefoot, had a higher rate of loading, and their loads were higher, than when they ran in traditional shoes.
- When they ran in Vibrams or barefoot, all runners showed reduced knee flexion, which is usually linked to lower rates of injury.
- But, when runners wore Vibrams, they showed more pronation, similar to when running in regular shoes, which could increase the risks of injury in the lower limbs that can come from overuse.
"Just because you put the Vibrams on your feet doesn't mean you'll automatically adopt the correct running stride."
Pete McCall, an ACE exercise physiologist, who has been exercising (but not running) in Vibrams since mid-2009 said:
"If you want to run in the Vibrams, you should be prepared to change your gait pattern."
You need to give yourself time adapt to them, he added.
"Running in Vibrams could be good for some if they adopt the appropriate running style."
He advised people to get "explicit" instruction and spend time practising how to land on the ball of the foot, as opposed to the heel. Otherwise people could do themselves more harm than good:
"Simply switching to Vibrams doesn't guarantee that a person is not going to experience more injuries," he cautioned.
Written by Catharine Paddock PhD