Two embedded force plat forms

Three-dimensional kinematic data were collected with a passive 10-camera system (VICON, Oxford Metrics, UK) at 250 Hz, while kinetic data were collected from two embedded force plat-forms at a sampling rate of 1000 Hz (AMTI, Watertown, MA, USA). Retro-reflective markers were placed on body landmarks of the lower extremities and rigid clusters on lateral surfaces of the thighs, legs and heel shoe counters to track motions during the walking test²⁵ . Kinematic and kinetics were calculated using Visual3D (C-motion, Germantown, MD, USA). Net joint moments were determined as external moments, normalized to the body mass (kg) and height (m) of each subject¹⁷ . Frontal and sagittal plane kinematics at baseline were both assessed, including: Peak Knee Flexion and Adduction Angles, Peak Knee Flexion and Adduction Moments, and Peak Knee Flexion and Adduction Moment Impulses during the stance phase of walking. All biomechanical variables can be seen in Table III.

Three-dimensional lower extremity kinematics were recorded using a 10-camera motion capture system (VICON, Oxford Metrics, Oxford, UK) at a sampling rate of 250 Hz. Ground reaction force data were obtained using two embedded force platforms (AMTI, Watertown, MA) at a sampling rate of 1000 Hz. Marker and ground reaction force data were collected and synchronized using motion capture software (Nexus, Oxford Metrics) while subjects walked at a self-selected speed. Kinematic and kinetic data were computed using Visual3D (C-Motion, Germantown, MD) and MatLab. Joint kinematics included: hip and knee flexion/extension, abduction/adduction and internal/external rotation angles and were not normalized to the standing calibration position. Joint kinetic data included moment and moment impulses; Joint moments were reported as external moments and normalized to each subject’s body mass (kg) and height (m). Knee moment impulses were calculated as the integral of knee moment (Nm/kg × m) with respect to time (msec).