ORBITAL STABILITY ANALYSIS OF HUMAN MOVEMENT: IN-SILICO AND EXPERIMENTAL PRELIMINARY EVALUATION ON A STAIR CLIMBING TASK

Orbital stability analysis was originally proposed for robotics application, and is a relatively novel and promising approach in biomechanics for analysing locomotor stability of cyclic motor tasks. It could give a new insight into the mechanisms that underlie the event of fall during daily tasks. The main criticality in the application of this approach to human movement is the poor characterisation of its sensitivity to experimental input parameters, e.g. minimum number of task cycles necessary for a reliable stability evaluation. To investigate these aspects, an in-silico orbital stability analysis on time series coming from a nonlinear model and a preliminary experimental evaluation of a stair climbing task were performed. In-silico analysis results showed that the minimum number of cycles to obtain significant orbital stability quantification is 10. Preliminary experimental orbital stability analysis results confirmed that stair climbing is a stable task for an healthy subject, showing numerically that single stance results less stable than double stance. This expected result [1] confirmed that the technique can be exploited to study human motor tasks.