The influence of forefoot varus on eccentric hip torque in adolescents

Hip strength impairments have been established as risk factors for lower limb injuries. Hip muscles strength might be influenced by foot misalignments, however this has not yet been verified. Forefoot varus (FV) has been shown to cause subtalar joint hyperpronation. Subtalar hyperpronation has been associated with excessive lower limb internal rotation in weight-bearing activities. Also, subtalar hyperpronation might result in greater ground reaction force dissipation at the foot. Consequently, there would be less demand for force dissipation at the hip joint, which could reduce the capacity for hip eccentric torque in these subjects. Therefore, the purpose of this study was to determine if FV influences the eccentric hip torque generation of young subjects. Forty-four sedentary, healthy adolescents were divided into 2 groups: subjects with FV (VG, n = 22) and subjects with neutral forefoot alignment (CG, n = 22). An isokinetic dynamometer was used to assess the eccentric torque generated in hip extension and external rotation in these subjects. Group differences were assessed using a one-way multivariate analysis of variance. The VG presented smaller eccentric torque for hip extension (P = 0.014) when compared to the CG, with no difference between groups in external rotation torque (P = 0.433). These results indicate that FV influences hip eccentric torque generation of young subjects. Considering that the muscles involved in hip extension are related to the stabilization of the lumbar spine, hip and knee, these findings bring further enlightenment to the role of foot misalignments as risk factors for injuries in the lower limbs and lumbo-pelvic complex in young subjects.