Kinematics and forces in the above-knee prosthesis during the stair climbing
The most modern generation of controlled AK prostheses is considered as important step forward in technology of manufacture of AK prostheses, since they offer the highest proximity to human walk. However, so far the problem of climbing the stairs by transfemoral amputee has not been resolved. The reason for unresolved problem of upstairs movement of persons with AK prosthesis lies in a need to introduce an external source of energy, which would provide the user with energy required for lifting a body when climbing the stairs. The kinematic analysis of movement of the AK prosthesis with a build-in hydraulic cylinder connected to an external source of power is intended to prove that there is a real possibility for a person with an AK prosthesis to climb stairs. An analysis was carried out of the prosthesis movement in a sagital plane for the period of climbing from the first contact of the artificial foot with the step of a stair until the moment of its separation. Trajectories of characteristic points on the prosthesis were recorded for the examinee climbing three staircases with different gradients: shallow SH (25o), moderate M (30o) and steep ST (36o). The reaction force on stair during the movement of an AK prosthesis is analyzed. For more detailed analysis of climbing of a transfemoral amputee, an analysis of reaction force of stair for healthy persons has been carried out. The ELITE system with two CCD cameras and a Kistler platform for measuring the force on the surface were used during measurements.