Turning Point Trajectory Analysis for Skiers

s p r i n g 2 0 0 7 www.insidegnss.com www.insidegnss.com s p r i n g 2 0 0 7 InsideGNSS 25 In many sports, the margin between victory and defeat may be a matter of a few hundredths of a second. Certainly that is true of skiing competition where the demands on equipment and the performance pressure on athletes are tremendous — and not just on elite skiers, but increasingly on participants at every skill level. In preparing for competition, every detail is important. Equipment is thoroughly tested and race preparation focuses on local factors (weather conditions, slope, quality of snow on the course, and so forth). Traditionally, development and testing of materials or equipment has been based on repeated measurements with resources including timing cells or wind tunnels. Similarly, the analysis of athletes’ performance has relied on techniques such as measuring race segments (chronometry) and video recordings. These methods, however, appear vulnerable to changing meteorological conditions and the difficulty of replicating the posture and movements of test subjects from one trial to the next due to such factors as improved performance stemming from cumulative experience in the trials or decreased performance due to fatigue. Furthermore, chronometry has a discrete character while researchers, coaches, and athletes are interested in observing certain phenomena continuously. Therefore, new methods are being sought that offer precise measurements during trials and subsequent evaluation of positions, velocities, accelerations, and forces. Turning point Trajectory Analysis for skiers