New Automatic Algorithms for Computing Characteristics of Three Dimensional Pelvic and Lower Limb Motions in Race Walking

Optical motion systems are precise and thus they may be applied in analysis of athletes' performance. It is particularly important in the analysis of motion in walker sports where pelvic rotation translates into movement speed. The aim of this paper is to present and test algorithms that can be used in analysis of the workload on the pelvic hyperextension at the knee, and the resulting movement speed during race walking. The test data were obtained by organizing a motion capture session whose participant was a woman professional race walker and a member of the National Senior Team. The algorithms presented compute parameters that strictly characterize race walking. They include: race walking speed, pelvic rotation angles and knee deflection angles. The test recordings were made using a Vicon motion capture system. The frame rate was set to 100 frames per second. The session was conducted in a shaded room so that no additional reflections appeared. The equipment was supplied with Vicon's Nexus 2.0 software, which was used for system calibration, data recording and data processing. The participant was measured for the purpose of creating and scaling a new subject, which was in turn required for computing the motion parameters. The results include computed pelvis rotation, knee flexion angles, walking speed as well as execution times of the proposed algorithms. Execution times are very short. The longest execution time of 0.15 seconds was recorded for a C3D file consisting of 192 frames and containing a recording of race-walking on the distance of 5.3 meters.