Do foot orthotics have an immediate affect on the gait mechanics of individuals with chronic incomplete spinal cord injury

Research regarding the effectiveness of foot orthotics during functional activities is primarily limited to the able-bodied population. No research determining the impact of orthotic intervention on specific gait mechanics of ambulatory individuals after spinal cord injury (SCI) has been identified, even though this group often exhibits poor foot and ankle alignment. Purpose. This research was designed to ascertain if orthotic intervention had an immediate effect on gait measures and frontal plane kinematics and kinetics in ambulatory individuals with SCI. Methods. Nine community ambulators with an American Spinal Injury Association “D” classification were recruited. Prior to testing subjects were measured and fitted with temporary orthotics. Testing included both shoe-only and orthotic conditions, administered in random order. A six-camera optical motion analysis system captured three-dimensional motion at 120Hz, while force plate and electromyographic (EMG) data, collected at 1200Hz, provided information regarding ground reaction forces and muscle activity, respectively. An inverse dynamic approach was used to calculate frontal plane joint angles, moments, and powers at the ankle, knee, and hip. Mean and peak EMG data were recorded from five subjects for qualitative comparison. Statistics. A 2 x 2 doubly multivariate repeated measures multivariate analysis of variance was used to discern the effect of orthotics on each leg. Results. Orthotics significantly increased the stance duration, step duration, and ratio of stance on the less-involved limb. Orthotics reduced the gait velocity, swing duration, maximum hip abduction angle, maximum ankle power generation, and the maximum knee power absorption on the less-involved limb. Only the maximum ankle supination angle from the more-involved limb was decreased by orthotic intervention. Qualitative results of the mean and peak EMG amplitudes suggest increases in tibialis anterior and rectus femoris muscle activity with orthotic intervention. Conclusions . There is an immediate effect of orthotic intervention on selected gait and biomechanical variables within the less-involved limb. There is less immediate influence on the more-involved extremity. Results of this study justify further research in this area.