Abstract

Purpose: Foot strike patterns influence landing mechanics, with rearfoot strike (RFS) runners exhibiting higher impact loading than forefoot strike (FFS) runners. The few studies that included midfoot strike (MFS) runners have typically grouped them together with FFS. Additionally, most running studies have been conducted in laboratories. Advances in wearable technology now allow the measurement of runners' mechanics in their natural environment. The purpose of this study was to examine the relationship between foot strike pattern and impacts across a marathon race.

Methods: 222 healthy runners (119 M, 103 F; 44.1±10.8 years) running a marathon race were included. A treadmill assessment was undertaken to determine foot strike pattern (FSP). An ankle mounted accelerometer recorded tibial shock (TS) over the course of the marathon. TS was compared between RFS, MFS and FFS. Correlations between speed and impacts were examined between FSPs. TS was also compared at the 10km and 40km race points.

Results: RFS and MFS runners exhibited similar TS (12.24±3.59g vs. 11.82±2.68g, p=0.46) that was significantly higher (p<0.001 and p<0.01, respectively) than FFS runners (9.88±2.51g). Additionally, TS increased with speed for both RFS (r=0.54, p=0.01) and MFS (r=0.42, p=0.02) runners, but not FFS (r=0.05, p=0.83). Finally, both speed (p<0.001) and TS (p<0.001) were reduced between the 10km and 40km race points. However, when normalized for speed, TS was not different (p= 0.84).

Conclusions: RFS and MFS exhibit higher TS than FFS. Additionally, RFS and MFS increase TS with speed, while FFS do not. These results suggest that the impact loading of MFS is more like RFS than FFS. Finally, TS, when normalized for speed, is similar between the beginning and end of the race.