A Procedure for Experimental Evaluation of the Sit-to-Stand for the Design of Assisting Devices

Sit-to-Stand can be considered the most common operation that can be performed in daily life. Standing up is a complex task characterized by the transfer from one stabilized posture to another with movement of all body segments except the feet. The transfer from sitting to standing and back requires both voluntary movement of different body segments that contribute to the change of posture and equilibrium control during an important displacement of the centre of gravity (COG) of the trunk. The trajectory of the COG is characterized by a movement forward and then backward with simultaneous vertical displacement. Consequently, the entire movement requires a strong coordination between posture and movement. In this paper an experimental procedure is described to track and record point trajectories and the orientation of the trunk during the sit-to-stand. This analysis will be used to get information for further design of novel assisting devices. Then, design requirements are given according to the numerical and experimental results.