EFFECTS OF ARCH HEIGHT OF THE FOOT ON ANGULAR MOTION OF THE LOWER-EXTREMITIES IN RUNNING

It has been suggested that a relationship exists between the height of the medial longitudinal arch of the foot and athletic injuries to the lower extremities. However, the functional significance of arch heigh t in relation to injury is not well understood. The purpose of this st udy was to determine the influence of arch height on kinematic variabl es of the lower extremities that have been associated with the inciden ce of injury in running in an attempt to pin some insight into a funct ional relationship between arch height and injury. The three-dimension al kinematics of the lower extremities were measured during running fo r 30 subjects using high-speed video cameras. A joint coordinate syste m was used to calculate the three-dimensional orientation of the ankle joint complex for a single stance phase. Simple, linear regression an alyses showed that arch height does not influence either maximal evers ion movement or maximal internal leg rotation during running stance. H owever, assuming that knee pain in running can result from the transfe r of foot eversion to internal rotation of the tibia, a functional rel ationship between arch height and injury may exist in that the transfe r of foot eversion to internal leg rotation was found to increase sign ificantly with increasing arch height. A substantial (27%), yet incomp lete, amount of the variation in the transfer of movement between subj ects was explained by arch height, indicating that there must be facto rs other than arch height that influence the kinematic coupling at the ankle joint complex. Additionally, the transfer of movement is only o ne factor of many associated with the etiology of knee pain in running . Therefore, it is suggested that a running-injury-related foot typolo gy based on arch height is not possible at this time.