Epidemiology of adolescent runners: non-rearfoot strike is associated with the Achilles tendon and lower leg injury

BackgroundFoot strike patterns during running are classified into two types: rearfoot strike (RFS) and non-rearfoot strike (NRFS). These patterns are considered biomechanical risk factors for running-related injuries (RRIs). However, limited research exists on the prevalence or incidence of RRIs associated with different foot strike patterns, particularly within training or clinical practice contexts. Therefore, this epidemiological study aimed to investigate the prevalence and injury risk ratio (IRR) of RRIs concerning different foot strike patterns.MethodsA total of 182 male Japanese adolescent runners were included. Participants completed a questionnaire regarding their RRIs over the past year and were filmed during their habitual high-intensity training sessions from the lateral side. Foot strike patterns were visually classified, with participants accordingly categorized into the RFS and NRFS groups. The prevalence and IRR for RRIs for each site were calculated in both groups. A chi 2 test was conducted to examine the relationship between RRI history and foot strike patterns.ResultsA total of 95 (52.2%) and 87 (47.8%) participants were included in the RFS and NRFS groups, respectively, with 124 (68.1%) participants experiencing at least one RRI in the past year. The NRFS group was significantly associated with a history of RRI in the Achilles tendon (P = 0.01) and the medial lower leg (P = 0.03). The prevalence of RRI in the Achilles tendon was 9.5% and 23.0% in the RFS and NRFS groups, respectively, with an IRR of 2.427 [1.168, 5.040]. The prevalence of RRI in the medial lower leg was 27.4% and 42.5% in the RFS and NRFS groups, respectively, with an IRR of 1.554 [1.033, 2.338].ConclusionsAdolescent runners with NRFS exhibit a higher risk of Achilles tendinopathy and medial tibial stress syndrome, highlighting the need for RRI prevention strategies tailored for each foot strike pattern.