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MOTION ANALYSIS SYSTEM JUMPIN’ AHEAD


ISP ATHLETES USING 3D SIMULATION SYSTEM TO MASTER TRIPLES, QUADS


by PETER ZAPALO For more than four years, U.S. International


Selection Pool (ISP) athletes have used a high- tech system to help them figure out how to exe- cute the most difficult jumps in competition. Te motion analysis system (MAS) is the


brainchild of Jim Richards of the University of Delaware and Tom Kepple of C-Motion Inc. Both Richards and Kepple are biomechanists, scientists who study the mechanics of human movement. Te project team later added gradu- ate student Kat Arbour, who was at the university pursuing her PhD in biomechanics. She used the system in part to collect data for her jump impact research.


Te MAS primarily impacts those who are learning triple jumps, triple-triple combinations (getting the second jump clean, in particular) and, of course, quadruple jumps. Te MAS takes a two-step approach: motion capture and then simulation. Te simulation uses a comput- er model of the skater’s performance to show the


athlete how to successfully perform a particular jump by improving his or her in-air body posi- tion.


First, the athlete is carefully marked with


highly reflective dots. Tis allows the computer to reconstruct an accurate 3D model of the ath- lete’s body. Next, the athlete is filmed attempting the jump that he or she wishes to analyze. Once the biomechanists confirm that they have a clean capture of the athlete’s jump attempt, the athlete and coach go into the analysis laboratory. Tere, they view two images on screen: one


showing what he or she actually executed and an- other showing a mathematical model based on the jump execution. However, the model can be posed — kind of like a virtual mannequin — and the athlete, coach and biomechanist can modify the positions of the athlete’s body and the timing of the jump. Once changes have been made to the model, the simulation will show how chang- es made would alter the jump. Te scientists are


Ashley Cain and Max Aaron are two of the athletes who have improved their jump technique through the motion analysis system.


usually able to show the athlete that by making small changes in rotational technique, e.g., elim- inating imbalances and getting into a tight posi- tion more quickly, the skater will be able to exe- cute the jump cleanly. Te key is that the system allows the athlete and coach to play the “what if game” and then see the results both visually and numerically — all without putting the skater’s body at risk.


U.S. champion Max Aaron used the system


to master his now-trademark quad Salchow with- in a couple of weeks of using the system. “It [the MAS] was not just helping my con- fidence, it was exciting to see myself on the screen rotating the jump,” Aaron said. “It was amazing to learn that it was such a tiny correction — a small change in my arms — that would make the difference of getting around cleanly.” Te MAS, Aaron’s coach Tom Zakrajsek


said, showed his star pupil that he had the proper technique and jump height, and only needed to pull into a tighter rotation to successfully com- plete the jump.


“Tis feedback eliminated much trial and er-


ror in the learning process,” Zakrajsek said. “Max could see that if he adjusted his arms inward just by a few degrees as opposed to adjusting other as- pects of the jump, it helped him narrow his focus on what specifically he needed to do to achieve the rotation.”


U.S. junior silver medalist Ashley Cain


probably holds the record for quickest correc- tion after using the system last summer. Cain is coached by her parents, Darlene and Peter Cain.


“I was trying triple flip-triple toe and I used the system in the morning,” Cain said. “I went out with my dad on the next [freestyle] session and started landing the combinations completely clean. Even now, when I have a bad day on the ice, my dad tells me to remember Delaware and how to get my arms and leg in tight. Tat usually does the trick. I also remember Dr. Richards tell- ing me to come back when I want to learn triple Axel!”


Dr. Richards reminds athletes that, despite some of the immediate successes they have seen, these technical changes do not happen overnight. He often uses an analogy of an athlete having an internal speedometer that tells the skater to limit his or her spin rate. “If someone asked you to drive your car at 200 miles per hour (on a closed track of course), you probably wouldn’t because you’d be worried


20 AUGUST/SEPTEMBER 2013


PHOTO COURTESY OF BY PETER ZAPALO


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