Much of the hype surrounding the recent barefoot running trend emanated from a study out of Harvard by Dan Lieberman and colleagues (2010). In that study, the authors investigated a group of barefoot runners, the Kalenjin of Kenya, and analyzed how their feet hit the ground when they ran. They found that barefoot runners were mainly forefoot strikers (they hit the ground near the ball of their foot), compared to those who have been running in shoes their entire lives, and were mostly rearfoot strikers (they hit the ground with their heels first). The authors also observed that heel striking resulted in a more rapid increase of reaction forces at the foot. From this, the researchers suggested that perhaps all humans ran with a forefoot style before shoes, and that this was a mechanism to possibly prevent injury. Many have taken the results of this study to suggest that everyone should be running barefoot, or at least, with a midfoot (striking the ground the instep or ‘middle’ of the foot) or forefoot strike pattern.
A recently published paper somewhat challenges this notion. This group, lead by Kevin Hatala (2013) analyzed a different group of barefoot runners, the Daasanach of Kenya. The authors found an interesting contrast to the Lieberman research team – they discovered that the majority of the runners in this group were rearfoot strikers! What explains this difference? The Lieberman group analyzed strike patterns of barefoot runners at a relatively fast pace (4:33 – 5:16 per mile), while the Hatala research group analyzed the barefoot runners at a variety of paces (from 4:30 -11:00 per mile). Hatala and colleagues did find that the likelihood of midfoot striking increased with increasing speed, but forefoot striking was not nearly as common with the Daasanach as it was with the Kalenjin. This finding is consistent with previous research which established that humans of all abilities tend to shift toward mid- and forefoot strike patterns as we approach our maximum running speed.
The results from this study strongly suggest that there is no one ‘correct’ way to run, and that it is likely that people may run differently depending on speed, surface, shoe style, and training history. With this in mind, issues might arise when we try to deliberately impose a particular style of running on a person because it is the ‘correct’ or ‘more natural’ way to run. We should be careful to consider one’s running history, preferred running distances, and running speeds when observing one’s running form or proposing shoe styles. If a runner is frequently injured, then perhaps a change in form may be appropriate. However, there are many other factors that have been shown to have strong correlations to injury risk – including a recent article suggesting that weak glutes may be partly responsible for runner’s knee (Wilson et al. 2012). A sudden and unwarranted change in running form or shoe style could be counterproductive if not accompanied by a very slow and gradual progression to allow the body to adapt to a very different set of stresses.
Cory Hofmann, M.S.
Research Project Manager
Cybex Research Institute
In response to Variation in Foot Strike Patterns during Running among Habitually Barefoot Populations.