The effect of gait modification on the external knee adduction moment is reference frame dependent

Abstract

Background: This study investigated the extent to which reference frame convention affects the interpretation of how gait modification alters the external knee adduction moment. Methods: Data were collected from a single male able-bodied subject performing three gait tasks: normal, toe out and medial thrust. The net external moment vector at the knee was expressed in five alternative reference frames: the femur anatomical frame, the proximal tibia anatomical frame, the distal tibia anatomical frame, the laboratory frame and a non-orthogonal knee joint coordinate system. For each reference frame, the knee adduction moment was taken as the component about the frame's anteroposterior axis. Find..