Kinematic and kinetic study of sit-to-stand and stand-to-sit movements towards a human-like skeletal model *

The movements of sit-to-stand and stand-to-sit are frequently executed on daily life. To develop robotic assistive devices for people with mobility problems, it is important to study how a healthy human performs these tasks. The goal of this study is to present a mathematical model based on acquired kinematic and kinetic data that represents a healthy human body performing these movements. The results revealed that the movements of sit-to-stand and stand-to-sit have symmetric ground reaction force, joint angles and torques. The joint angles and the torques are very similar between each leg. The knee and the hip show more variation of the angle and achieve higher values of torque in comparison to the ankle. Although, ankle has higher torque during standing position. The ground reaction force shows that it is necessary to create an additional force to the weight force to achieve the final position of the movement. The acquired data describe as expected the sit-to-stand and stand-to-sit movements and can be used, in the future, to validate the presented model.