Comparison of impact accelerations between injury-resistant and recently injured recreational runners

INTRODUCTION/PURPOSE: Previous injury has consistently been shown to be one of the greatest risk factors for running-related injuries (RRIs). Runners returning to participation following injury may still demonstrate injury-related mechanics (e.g. repetitive high impact loading), potentially exposing them to further injuries. The aim of this study was to determine if the magnitude (Peak(accel)) and rate of loading (Rate(accel)) at the tibia and sacrum differ between runners who have never been injured, those who have acquired injury resistance (runners who have not been injured in the past 2 years) and those who have been recently injured (RRI sustained 3–12 months ago). METHODS: Runners completed an online survey capturing details of their RRI history over the previous 2 years. Never injured runners were matched by sex, quarterly annual mileage and typical training speed to runners who had acquired injury resistance and to runners who had been recently injured. Differences in Peak(accel) and Rate(accel) of the tibia and sacrum were assessed between the three groups during a treadmill run at a set speed, with consideration for sex. RESULTS: A total of 147 runners made up the three injury status groups (n: 49 per group). There was a significant main effect of injury status for Peak(accel) and Rate(accel) at the sacrum, with recently injured runners demonstrating significantly greater Rate(accel) than never injured and acquired injury resistant runners. There was also a significant main effect for sex, with females demonstrating greater tibial Peak(accel), sacrum Peak(accel) and Rate(accel) than males. CONCLUSION: Rate(accel) at the sacrum distinguishes recently injured runners from never injured runners and runners who may have acquired injury resistance, potentially highlighting poor impact acceleration attenuation in recently injured runners.