Do more flexible feet explain differences in injury risks and patterns between female and male middle-distance runners?

Running-related injuries (RRI) are multifactorial and their prevalence is influenced by a variety of internal and external risk factors, such as age, training volume and distance. However, even when accounting for these, females have been shown to have a greater risk of RRI than males, the mechanisms of which are not clearly understood. This study aimed to investigate gender differences in foot mobility, lower limb function and injury history in middle-distance runners. Twenty-six runners (13 males and 13 females) who ran between 30-40km per week participated in this study. Foot mobility, lower limb function and gait were assessed through a variety of static clinically recognised tests (Foot Posture Index, Windlass Mechanism, Supination Resistance and Single Leg Squat Tests) and dynamic 2-dimensional video analysis. Results showed 73.1% of participants reported history of RRI. Patterns of injuries differed, such that in females hip (33.3%), ankle (33.3%) and foot injuries (33.3%) were most common while males reported knee (40%), shank (30%) and foot injuries (20%). Significant differences in injury prevalence were, however, only identified for the knee and hip (p<0.05). Females had more pronated and flexible feet than males, with a positive relationship between injury occurrence and supination resistance in females (p<0.05). Data in this study provided provisional evidence for different foot characteristics and mechanisms of RRI in female and male runners, which should be considered in training strategy. Further research should consider how joint mobility and hormonal status affects biomechanics to develop strategies to protect runners through exercise, footwear and gait education.