Abstract: Objective To establish a new processing method for gait data on Matlab to evaluate the hindlimbs behavior of non-human primates. Methods Gait analysis was tested on three rhesus monkeys 6 weeks after spinal cord injury, and kinematics data of hindlimbs were obtained using the VICON system. The raw data of kinematics were filtered and extracted, which were achieved through VICON 3D motion capture system with the Excel link combining Matlab with Microsoft Excel, and calculated in the Matlab environment. Results The kinematic parameters such as step length, step height, knee joint angle, and malleolus joint angle were gained by calculating. The mean values of step length (F=2.869, P=0.088) and step height (F=1.148, P=0.344) showed no significant difference at three speeds, which implied a higher repeatability of the data model. Angle-time curve reflected the joint function and movement. This system initially described the foot gait trajectory which could be used in gait repetitive analysis, and also generated the gait 2D/3D trajectories of hindlimbs. Conclusion The implement of these functions makes the post-processing of data more flexible and open whitout VICON system, and the calculated parameters and space tracing of gait trajectory basically meet the need of hindlimb behavior evaluation for nonhuman primate.

Key words: non-human primates, gait, data processing, Matlab, gait parameters, gait trajectory, monkeys