Abstract

Three common data smoothing techniques, i.e. digital filter, spline function, and five-point moving arc, were applied to the trajectory-time coordinates of b arbell motion for a snatch and clean lift performed by a world champion weightlifter in order to determine the associated kinematics. Film data were collected during an international competition. The results showed that all three smoothing techniques produced similar kinematic values for barbell trajectory, velocity, and acceleration. For the digital filter method, optimal cut-off frequencies for the snatch lift were determined to be 4 Hz for vertical motion and 5 Hz for horizontal motion. For the clean lift the corresplonding values were 5 and 6 Hz, respectively. Optimal error estimates for the spline function method were 2.7 mm for both movement directions. Due to the simplicity of themoving arc technique, and the close agreement of kinematics obtained in comparison with the other two methods, it seems appropriate and advantageous to use the moving arc method in weightlifting analyses. Verf.-Referat