Spatiotemporal characteristics of habitually shod runners change when performing barefoot running

Abstract

Habitually shod rear-foot strike (RFS) runners demonstrate changes in spatiotemporal variables when running barefoot; however, it is unknown whether these changes are a function of running barefoot and/or adopting different foot-strike patterns. Therefore, the purpose of this study was to examine changes in spatiotemporal variables when habitually shod RFS runners transition to barefoot running. Inverse dynamic methodology was used to examine 22 habitually shod RFS runners who performed overground running, shod and barefoot. Runners were grouped according to their novice barefoot foot-strike pattern: RFS, mid-foot strike (MFS) and forefoot strike (FFS). Runners were also grouped to examine differences between shod and barefoot running. Of the 22 RFS shod runners, 5 adopted a FFS, 9 adopted a MFS, and 8 maintained a RFS during novice barefoot running. We report a significant main effect of running barefoot for spatiotemporal variables, but not for foot-strike pattern. Relative to when shod, all groups of runners took shorter strides and steps. RFS and MFS runners also exhibited higher step frequency and exhibited shorter step and cycle times, while RFS and FFS runners both exhibited shorter stance times. These findings indicate that barefoot running has a significant influence on spatiotemporal measures, regardless of utilized foot-strike pattern.