Abstract

The purpose of this research was to evaluate the estimation methods of the hip joint centre (HJC) location for calculating kinematic parameters of knee and hip joints during dynamic movement, in this reserch, instep kicking motion. Twelve skilled soccer players participated in the experiment. To estimate the HJC location, they were instructed to do ad hoc movements including hip flexion/extension and abduction/adduction movements performed on several planes of different orientations, followed by a circumduction movement. Then, subjects performed their maximal instep kick, which were recorded using motion capture system at 250Hz. The coordinates of the HJC were estimated using three methods and compared. The first used marker coordinates on left and right greater trochanters, the second empirical relations between the HJC location and the length between anterior superior illiac spines, which had been called predictive method, and third bias compensated least squares method, which had been called functional method. Then, maximal hip extention and knee flexion angles during instep kicking motion were calculated based on three methods, and compared statistically. As a result, the hip joint centre location estimated by first method changed so much in the pelvic anatomical frame during dynamic exercise, and maximal hip extension and knee flexion angles were different from results by other two methods significantly. However, predictive methods gave almost the same results as functional method which had been said to be most accurate method in a previous study. Consequently, method using markers on the greater trochanters could not be appropriate for kinematic analysis during dynamic exercise, and predictive method was recommended for use because of its accuracy and easiness for application. Verf.-Referat