A motion simulation and biomechanical analysis of the shoulder joint using a whole human model

The analysis of movements and forces of human or animal subjects is useful in both the real and virtual worlds. We proposed the design of a computer model which simulates the movements at the shoulder joint for a specific subject and analyses the three-dimensional forces and torques produced at that joint during movement. The model was constructed using the mathematical dynamic modelling software (Madymo®). Anthropometric data were collected from a healthy volunteer in the form of weight, height, limb lengths, and the centre of mass deduced. A group of reflective markers were attached to specific areas on the subject´s body while he performed a group of precise movements, i.e. flexion/extension, adduction/abduction and rotation all at the shoulder. The marker data were collected using a motion capturing system. Shoulder joint angles were obtained using the in-house designed software, and then input into the computer model to simulate the subject´s movements allowing analysis of the forces and torques. Results showed that the model successfully simulated the movements and predicted shoulder joint force and torque during movements, corroborating with the theory of biomechanics. Preliminary results are encouraging. Currently, the focus is on extending the application into the clinical practice, sports exercise and behavioural animation environments.