AnyGait

Movement analysis has now become an important clinical tool to diagnose gait disorders. Specialist physicians are able to diagnose problems by inspecting the pattern of ground reaction forces, the nature of anatomical joint angles, joint torques and power. However, an estimation of muscle forces during a gait cycle will give precise information for the treatment of gait pathologies, particularly, in surgical cases. In this perspective, a universal gait model is being developed.

This is the first gait model using the different segments, joints and muscles of the lower extremity available in the full body repository. The lower extremity is modeled with 7 rigid segments (Thigh, Shank and Foot for both legs and the Pelvis) and 35 muscles in each leg. The hip joints are considered as spherical joints, where as the knee and ankle joints are considered as revolute joints. The drivers of the model are specified by joint angles. However, the origin of the pelvis is moved as well as it is rotated. Four force plates are provided for the gait analysis and they are labeled as: Left First, Left Second, Right First and Right Second. For 100% gait cycle, three force plates, namely, Left First, Right First and Right Second are required. The sample data is made from gait cycle data files, popularly known as GCD files. Since these are anatomical angles, there is a discrepancy in the movement. The direct computation of Euler angles from marker data available in binary C3D file or APAS 3D files is being worked out. An assisting standalone program, AnyGait (AnyGait.zip containing AnyGait.exe and AnyGait.pdf), is being developed for this purpose. Nirjhar Dhang (nirjhar@civil.iitkgp.ernet.in) is developing this model and the assisting program, and he may be directly contacted for any queries or improvement suggestions.