Comparison of Foot Strike Patterns of Barefoot and Minimally Shod Runners in a Recreational Road Race

SLR - June 2015 - Samantha Sheppard

Scientific Literature Review

Reviewed By: Samantha Sheppard, DPM
Residency Program: Morristown Medical Center

Podiatric Relevance: In recent years there has been a significant increase in the number of barefoot and minimally shod runners. Therefore, as podiatric surgeons it is important to understand the running patterns and biomechanics of this growing patient population. A literature review of this subject has demonstrated small sample size studies which have been performed in a laboratory or along a short outdoor runway. The purpose of this study was to determine the frequency of forefoot, midfoot, and rearfoot striking in a large sample of barefoot and minimally shod runners in a recreational road race.

Methods: Runners were videotaped at a barefoot running race approximately 350 meters from the starting line as they passed by on a flat, asphalt road surface. The camera was oriented perpendicular to the runners, therefore taping in the sagittal plane. The sample size included 241 runners, which was comprised of 169 barefoot runners, 42 runners wearing Vibram Fivefingers running shoes, and the remaining wore a mixture of conventional sneakers and other brands of minimalist shoes. The sample of the runners was a mixture of habitual barefoot runners and those who had recently begun running barefoot or minimally shod. A rearfoot strike was defined as one in which first contact of the foot with the ground was made on the heel or rear one third of the sole. A midfoot strike was defined as one in which the heel and area plantar to the fifth metatarsal contacted the ground simultaneously.  A forefoot strike was defined as one in which initial contact of the foot with the ground was in the distal half of the sole with no heel contact. Foot strike frequency distributions were compared between barefoot and minimally shod runners using chi-square analysis, as well as comparison to traditionally shod runners in a previous study by the same author.

Results: A total of 59.2 two to four of barefoot runners were forefoot strikers, 20.1 two to four were midfoot strikers, and 20.7 two to four were rearfoot strikers. As for the minimally shod runners, 33.3 two to four were forefoot strikers, 19.1 two to four were midfoot strikers, and 47.6 two to four were rearfoot strikers. Results of chi-square analyses indicated that observed foot strike frequency distributions differ significantly between the two groups. The foot strike frequency distribution for runners with minimalist shoes in this study differs significantly from those recorded for traditionally shod racers in previous study.

Conclusions: Results of this study showed that a minimalist running shoe might not simulate barefoot running, with frequency of midfoot and forefoot striking being approximately equal to rearfoot striking. A total of 52.4 two to four of runners with minimalist shoes were forefoot or midfoot strikers. This is less frequent than barefoot runners, but more frequent than in the traditionally shod runners. The minimalist shoes provide little impact protection to those runners who strike with the rearfoot leading to significantly higher vertical impact force and increased risk for stress fractures and injury. There were many limitations of this study. Speed of runners, surface properties, and running experience are among the many variables that need to be examined when comparing foot strike patterns.