The purpose of this study was to:
1) develop a model that would be adequate in analyzing the sit to stand (STS) transfer motion
2) examine individual muscle forces, their contributions to the acceleration of the center of mass, as well as inter-limb differences in muscle forces produced during the STS transfer in a young, healthy population.
Our STS transfer analysis required a three-dimensional musculoskeletal model that had lower extremities, flexibility in the lumbar vertebrae, and arms. Capturing the dynamics of the lower back and arms was critical for 1) ensuring more dynamically accurate calculations of muscle forces and induced accelerations and 2) developing benchmark simulations for young healthy adults using a model that could be applied in future studies to capture possible compensatory strategies (e.g., the use of arms or torso) in various populations completing the STS transfer. Because no previously developed model met these criteria, we created a three-dimensional musculoskeletal model, the Full Body Model 2016, by combining these models: Lower Limb Model 2010, Musculoskeletal Model of the Lumbar Spine, MoBL-ARMS Upper Limb Model, and Head and Neck Musculoskeletal Biomechanics Model. It has 46 degrees of freedom with 194 Hill-type muscle-tendon actuators. A description of how the model was assembled and evaluated is in Appendix 1 of our manuscript, Muscle Forces and Their Contributions to Vertical and Horizontal Acceleration of the Center of Mass during Sit-to-Stand Transfer in Young, Healthy Adults (see publications).
Watch this video to get a sneak peek of STS transfer simulation with the Full Body Model 2016.
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