A Perturbation Study of Lower Extremity Motion during Running

The present study explored kinematic adaptation in the lower extremity to running in shoes with 10° valgus and varus midsole perturbations. Rearfoot motion and knee flexion/extension data on nine subjects were collected using a Selspot II system during treadmill running in the two test shoes and in a neutral shoe condition. Maximum pronation was significantly altered by an amount approximately the same as the shoe perturbation, but there was no substantial adaptation in the amount of knee flexion. From the rearfoot patterns it was inferred that time to maximum pronation may be an unreliable variable to describe the pattern of rearfoot motion; the two-phase profile using rearfoot velocity may be more useful. It was concluded that certain subtle sagittal plane kinematic adaptations in timing and velocity patterns did occur at the knee in response to the shoe perturbations.