Multibody kinematics optimization based on synergies to track the motion of all foot bones with a standard gait protocol

The measurement of foot kinematics in gait analysis is generally performed through stereophotogrammetric optoelectronic systems and skin markers, clusters of skin markers and multi-segment protocols [1]. However, motion track is impossible for several bones because of the limited access, such as the talus. In addition, measurements are affected by soft tissue artifact (STA). Multibody kinematics optimisation (MKO) may improve gait analysis results by introducing kinematic models that reproduce the natural human movement. These models are fitted on marker motion during the inverse kinematics computation, obtaining estimates of position and orientation of relevant bones while reducing the error associated with STA [2]. The aim of this preliminary study is to use the foot synergies [3] to perform the MKO on the foot. We hypothesized that the method should reduce the STA impact, obtaining at the same time the kinematics of all the bones of the foot.