A CAE BASED APPROACH TO DYNAMIC WHOLE-BOD Y MODELING - THE FORCES ACTING ON THE LUMBAR SPINE DURING ASYMMETRIC LIFTING

Biomechanical models of the human body play an important role in the a nalysis of the mechanical loading of the musculo-skeletal system. The whole-body model presented in this paper is based on a CAE (Computer A ided Engineering) program that permits the dynamic simulation of compl ex systems of rigid bodies. The model we developed on this basis consi sted of 19 segments and 18 joints. The experimental data are derived f rom the 3D motion analysis system VICON, which is provided with 5 came ras, a force-plate and a 10-channel EMG recorder. The kinematic data a re fed into the simulator after first being processed in a special man ner to generate drivers for joint angles. The model was first used to calculate the compression forces generated within the lumbar spine dur ing the asymmetric lifting and putting down of a 15 kg stone. The quas istatic calculation shows a dynamic contribution to the compression fo rces generated during the lifting of 11%. Increasing or decreasing the inertial moments of the segments by the factor 2 had an effect of les s than 1% with the identical movement.