The purpose of this study was to compare joint couplingpatterns and variability of the rearfoot and tibia during running in subjects who were treated with two types of orthotic devices to that of controls. Eleven subjects with various lower extremity injuries were treated unsuccessfully with a standard orthotic, and then successfully with an inverted orthotic. Three-dimensional kinematic data were collected while subjects ran without orthoses and then in standard and inverted orthoses. Eleven healthy subjects ran without orthoses for comparison. The rearfoot inversion/eversion and tibial internal/external rotation joint couplingpattern and variability relationship was assessed usinga vector codingtechnique. It was hypothesized that when the treated runners ran without orthotic devices, they would exhibit lower joint couplingangles and lower joint couplingvariability compared to the controls. In addition, it was hypothesized that there would be no difference in the couplingangle or couplingvariability between the standard and no orthotic conditions of the treated runners. Finally, it was hypothesized that couplingangle would decrease and variability would increase in the inverted versus the standard and non-orthotic conditions. No significant differences in joint coupling pattern or variability were observed between the treated and control subjects. In addition, no significant differences were noted between the orthotic conditions in the treated group. These results suggest that foot orthotic devices do not produce significant changes in rearfoot–tibial coupling. Therefore, the relief experienced with the inverted orthotic is likely due to factors other than alterations in this coupling.
