BIOMECHANICAL ANALYSIS OF DISCUS THROWING AT 1996 ATLANTA OLYMPIC GAMES

Abstract

INTRODUCTION This project involved collecting video records of the discus throwing at the 1996 Atlanta Games, immediately uploaded the data to the Internet and analyzing the discus performances of the top four performers. METHODS Three video cameras positioned at distances from 50 to 80m recorded all discus throws at 60fps which were converted to Avi digital format and uploaded to the Internet. One camera was located at the back of the circle, camera 2 was to the side and camera 3 was situated, 45 deg. to the left-front of the circle. Dimensions of the circle and anatomical landmarks served as 9 calibration points used in the DLT conversion of 21 data points to real coordinates which were smoothed at 10 Hz with a digital lowpass filter. Verification of the circle s 250 cm diameter resulted in an average error of 2.9 cm (1.2%), range (0.6 cm to 3.4 cm) with trial errors ranging from 0.6 to 3.4 cm. RESULTS 1. The resultant release velocities calculated for the best 4 throws were 3080,27 19,2599, and 2498 cmlsec for Riedel, Dubrovschchik, Kaptyukh, and Washington, respectively. 2. Corresponding heights of the release of the discus were 1.5, 1.8, 1.6, and 1.2m for the top 4 throwers. 3. The elapsed times to complete the turns of the throw were 3.0,2.3, 1.9, and 1.6 sec for Riedel, Dubrovschchik, Kaptyukh, and Washington, respectively. 4. The combination of projection velocity, angle, and height of release resulted in medalist throws of 69.4 m (OR) by Riedel, 66.6 m, 65.8 m, and 65.4 m for Dubrovschchik, Katyukh, and Washington. The aerodynamic effect of the angle of attack was not determined. CONCLUSION Riedel, the gold medalist generated the fastest discus projection velocity (3170 cdsec) while taking the longest time to complete the throwing movement. In contrast, Washington took 46% less time but threw 28% slower. This would indicate that Washington s movement across the circle was too fast or the return of the stored elastic energy of the arm to the discus.