The ground reaction forces are measured with two Kistler Force Plates (Kistler Instruments, Inc., Amherst, NY). Using the motion analysis data along with ground reaction force we calculate the joint moments (kinetics) required for walking.
The Kistler Force Plates use triaxial piezoelectic force transducers mounted at the corners of each plate to measure the three components of the ground reaction force vector (vertical, anterior-posterior, and medio-lateral) throughout the stance phase of gait. For comparing data between different subjects and/or sessions, the joint moments are normalized to body weight.