Objective: To investigate if running distance to first running-related injury varies between foot postures in novice runners wearing neutral shoes.
Design: A 1-year epidemiological observational prospective cohort study.
Participants: A total of 927 novice runners equivalent to 1854 feet were included. At baseline, foot posture on each foot was evaluated using the foot-posture index and categorised into highly supinated (n=53), supinated (n=369), neutral (n=1292), pronated (n=122) or highly pronated (n=18). Participants then had to start running in a neutral running shoe and to use global positioning system watch to quantify the running distance in every training session.
Main outcome measure: A running-related injury was defined as any musculoskeletal complaint of the lower extremity or back caused by running, which restricted the amount of running for at least 1 week.
Results: During 1 year of follow-up, the 1854 feet included in the analyses ran a total of 326 803 km until injury or censoring. A total of 252 participants sustained a running-related injury. Of these, 63 were bilateral injuries. Compared with a neutral foot posture, no significant body mass index-adjusted cumulative risk differences (RD) were found after 250 km of running for highly supinated feet (RD=11.0% (-10% to 32.1%), p=0.30), supinated feet (RD=-1.4% (-8.4% to 5.5%), p=0.69), pronated feet (RD=-8.1% (-17.6% to 1.3%), p=0.09) and highly pronated feet (RD=9.8% (-19.3% to 38.8%), p=0.51). In addition, the incidence-rate difference/1000 km of running, revealed that pronators had a significantly lower number of injuries/1000 km of running of -0.37 (-0.03 to -0.70), p=0.03 than neutrals.
Conclusions: The results of the present study contradict the widespread belief that moderate foot pronation is associated with an increased risk of injury among novice runners taking up running in a neutral running shoe. More work is needed to ascertain if highly pronated feet face a higher risk of injury than neutral feet.
Keywords: Gait analysis; Injury Prevention; Lower extremity injuries; Running; Running shoes.