Footwear matters: influence of footwear and foot strike on load rates during running

Abstract

INTRODUCTION: Running with a forefoot strike (FFS) pattern has been suggested to reduce the risk of overuse running injuries, due to a reduced vertical loadrate compared with rearfoot strike (RFS) running. However, resultant loadrate has been reported to be similar between foot strikes when running in traditional shoes, leading to questions regarding the value of running with a FFS. The influence of minimal footwear on the resultant loadrate has not been considered. This study aimed to compare component and resultant instantaneous loadrate (ILR) between runners with different foot strike patterns in their habitual footwear conditions. METHODS: 29 injury-free participants (22 males, 7 females) ran at 3.13m.s along a 30m runway, with their habitual foot strike and footwear condition. Ground reaction force data were collected. Peak ILR values were compared between three conditions; those who habitually run with a RFS in standard shoes, with a FFS in standard shoes, and with a FFS in minimal shoes. RESULTS: Peak resultant, vertical, lateral and medial ILR were lower (P < 0.001) when running in minimal shoes with a FFS than in standard shoes with either foot strike. When running with a FFS, peak posterior ILR were lower (P < 0.001) in minimal than standard shoes. CONCLUSIONS: When running in a standard shoe, peak resultant and component instantaneous loadrates were similar between footstrike patterns. However, loadrates were lower when running in minimal shoes with a FFS, compared with running in standard shoes with either foot strike. Therefore, it appears that footwear alters the loadrates during running, even with similar foot strike patterns.