This page contains a Flash digital edition of a book.


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



Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76