A Biomechanical Comparison Of Single, Double, and Triple Axels
Keywords:winter sport, figure skater, axels
AbstractTo be competitive at the national and international levrels, figure skaters today must perform complex athletic skills such as triple axels and quadruple toe loops. While numerous skaters now attemping these jumps in competition, very few are executing them consistently, particularly at the end of their program or in combination with other jumps. In this study, a 3D kinematic analysis of five elite male skaters was undertaken to compare characteristics of single, double, and triple axels. If figure skating coaches can learn what these skaters do differently when executing a triple axel as compared to a single or double axel, perhaps they will be able to more successfully teach this difficult skill to developing skaters. In this study, three 60 Hz video cameras were focused on a "jump zone" in which skaters were instructed to take off for all jumps. Three attempts of each jump type per skater were recorded, and each skater's best jump of each type, as evaluated by two coaches, was digitized using the PEAK Performance, Inc. motion analysis system. Numerous kinematic parameters including jump height, take-off angle, take-off velocity, and rotational velocity were computed and compared for the different jump types and different skaters. Additional measurements such as jump distance, skid distance, and skid width were made from skaters' marks on the ice. The results of this study show that despite diversity in skaters' indivitual jump styles, consistent differences between single, double, and triple axels can be observed. For example, skaters increase their number of revolutions by increasing their rotational velocity, not by increasng their jump height or time in the air. The study also shows that skaters triple axels travel only 70 percent of thc distance of their single axels, an observation attributable to skaters' greater skid distance, greater take-off angle, and consequently lower horizontal velocity at take-off in their triple axels as compared to their angle or double axels. Such observations suggest that achieving a high rotational (in excess of 5 revolutions per second) by generating angular momentum at take-off and by "pulling in" tightly to minimize the moment of inertia about the spin axis is a key to consistently performing the triple axel jump.