Anatomically-based, subject-specific modelling of lower limb motion during gait: PhD study

Musculoskeletal models, in combination with data from 3D gait analysis, allow investigation of muscle function during walking. The assessment of muscle function is of particular importance in a medical context if dysfunction of the neuromuscular system has resulted in impaired gait. Muscle structures in clinical gait analysis have commonly been modelled using a series of straight-line segments. This geometric simplification has significantly restricted the application of these models to more detailed analyses of muscle function during walking. The present PhD study was a combined effort between the Auckland Bioengineering Institute and the Department of Surgery, University of Auckland, for introducing anatomically-based, subject- specific modelling techniques into clinical gait analysis. In particular, the aim was to explore the potential use of anatomically-based musculoskeletal models in medical research related to Cerebral Palsy (CP). Three fields had to be merged in order to reach this target: subject-specific modelling of the musculoskeletal system, 3D gait analysis, and inverse kinematics for deriving soft-tissue deformation. The outcome of the present work has provided new insights into the architectural alterations in spastic muscles of children with CP, has demonstrated the usefulness of geometric- based modelling techniques in predicting muscle deformations during walking, has highlighted the errors that affect the accuracy of modelled muscle-tendon lengths, and has set the foundation for using 3D visualisation techniques in facilitating the teaching of gait.