THE EFFECT OF SOFT FOOT ORTHOTICS ON 3-DIMENSIONAL LOWER-LIMB KINEMATICS DURING WALKING AND RUNNING

Background and Purpose. Although foot orthotics are often prescribed t o alter the lower-extremity, mechanics during the stance period of gai t, there is little documentation of the actual effect of foot orthotic s on the movement of the lower-extremity joints during walking and run ning This study examined the effect of foot orthotics on the range of motion of the talocrural/subtalar joint and the knee joint in three di mensions during walking and running Subjects. Ten female adolescent su bjects, aged 13 to 17 years ((X) over bar 14.4, SD=1.1) who were diagn osed with patellofemoral pain syndrome and exhibited forefoot varus gr eater than 6 degrees and/or calcaneal valgus greater than 6 degrees pa rticipated in the study. Methods. Thirty strides of walking and runnin g on a treadmill were recorded for each of the orthotic and nonorthoti c conditions for each subject using an optoelectronic recording techni que. Analyses of variance for repeated measures were performed on the range of motion of the talocrural/subtalarjoint and knee joint for eac h plane of motion (ie, six separate analyses). The main factors of eac h analysis were the effect of the orthotic (orthotic condition versus nonorthotic condition), mode of ambulation (walking and running), and phase of the stance period (contact, midstance and propulsion). Result s. No differences were found in sagittal-plane movements. Reductions o f 1 to 3 degrees occurred with orthotic use for the talocrural/subtala rjoint during walking and running in the frontal and transverse planes . The orthotics reduced knee motion in the frontal plane during the co ntact and mid-stance phases of walking, but increased the motion durin g the contact and mid-stance phases of running. Conclusions and Discus sion. This study shows that corrections to the static position of fore foot varus and calcaneal valgus can result in changes in transverse- a nd frontal-plane motion of the foot and knee during walking and runnin g.