ABSTRACT
Computer-Aided Engineering (CAE) is now an indispensable tool in the industry and has made major contributions to machine design. For example, the finite-element-based modeling approach (e.g. Verver et al. 2004) and the rigid-body mechanics-based model approach (e.g. Langsfeld et al. 2000)
public-domain library of body models, can address the limitations mentioned above by estimating muscle forces in working conditions. The OpenSim platform, which is free and open-source musculoskeletal modeling software (Delp et al. 2007), may provide an important alternative to such commercial packages. Christophy et al. (2012) recently published a detailed lumbar spine model in OpenSim. However, it lacked upper extremity, lower extremity and head-neck components, which must be added to model relevant working postures. Moreover, validation of the model was limited to the predictions of moment arms of the low-back muscles during flexion-extension motions, and did not examine muscle or joint reaction forces. Therefore, this paper aims to: (1) add upper extremities, lower extremities, and head and neck in the model; and (2) validate vertebral loading calculated by the model using in vivo measurements found in the literature. The resulting model will provide the ability to simulate and study lumbar loading under different working conditions to improve the ergonomics of machine design.
