Can Figure Skaters Master the Head-Spinning Physics of a Quintuple Jump?

When American figure skater Nathan Chen performs at this year’s Winter Olympics, he’ll be looking to make history. The first and only skater in the world competing with five different types of quadruple jump—the salchow, loop, toe loop, flip, and lutz—he is poised to become the first athlete in the sport’s history to execute these five variations in a single program. It would be another iconic first for Chen, who last year, at the age of 17, became the first person to land five quads in a single performance.

“He has defined the current limit of the sport,” says retired figure skater Tim Goebel, an Olympic bronze medalist who, in 1998, became the first American figure skater to land a quadruple jump in competition. Once known as the “Quad King,” Goebel has watched quads transform from a nigh-impossible feat into an essential element in the routine of any male figure skater hoping to compete at the elite level—a transformation that has culminated with Nathan Chen. “For the time being,” Goebel says, “he’s set the standard.”

For the time being. As in: Greater aerial feats await. Even as recently as a few years ago, a quintuple jump seemed out of the question. But today, Goebel says, it seems more like a matter of when than if.

Exactly when is difficult to say. But even harder to say is how. “I really don’t think a quint is possible,” says James Richards, a kinesiologist at the University of Delaware and an expert in the dynamics of figure skating spins. Using high speed cameras and motion-capture equipment, Richards has worked with many of the best figure skaters on Earth to deconstruct triple and quadruple jumps into their anatomically dependent variables, and explore the physiological limits to factors like hang time and rotations per minute.

Consider the vertical leap of a spinning figure skater, which isn’t as high as you might expect. Men who perform quads rarely clear 18 inches (many NBA players, by comparison, post standing vertical leaps in excess of 30 inches). That’s partly because skates are heavy, but it’s also because figure skaters have to balance the energy they put into their jump with the energy they put into their rotation. With a foot and a half of air, figure skaters have less than two-thirds of a second to perform their spins.

To pull off a quad, they need an average rotational frequency of around 340 rpm—but their peak rotational frequency is typically 80 to 100 rpm higher. By whipping their arms and legs in towards their bodies as soon as their jump begins, a skater keeps their mass as close to the axis of rotation as possible, decreasing their moment of inertia. Because the skater’s angular momentum remains the same, their rotational frequency gets a boost—to greater than 400 rpm—to compensate. (At its highest setting, a typical Kitchenaid stand mixer spins at 255 rpm.)

But to pull five rotations in the air, skaters will need to spin even faster—and Richards doesn’t think they can. “On the quad, we see the arms coming almost right in against the body which means they’re maxing out their in-air position,” he says, and they do it the instant their skates leave the ice. “So there’s really no way for them to get tighter to spin faster.” He points to his measurements. An athlete performing a quint would require an average rotational speed of around 400 rpm and a peak rotation of close to 500 rpm. “But the highest we’ve ever seen in the lab is in the 430, 440 range,” Richards says. “So I really don’t think we’re going to see quints any time soon—at least, not without assistance.” (The New York Times reports that Nathan Chen tops out a little shy of 440.)

What kind of assistance? New skate tech could do it; a boot with a pivoting hinge could give skaters an improved range of motion, for more powerful launches. Weighted gloves could help, too. Having the extra mass far from their axis of rotation upon takeoff would increase a skater’s angular momentum, causing them to spin faster than normal when they brought the weights in toward their bodies. “If skaters were to use that weight and were able to pull their arms to the same position, they would end up with a higher rotation speed during the jump,” says Sarah Ridge, a biomechanist at Brigham Young University who has studied the spin-boosting effects of weighted gloves. At least, that’s the idea. Weirdly, Ridge found that test subjects in gloves as light as six ounces tended to over-rotate on their first few jumps—suggesting that the weight does, in fact, help increase spin. But the skaters quickly adapted to the presence of the weights, and after a few more tries had returned to their normal spin rates.

Goebel, for one, is unmoved by Richards’ metrics. He thinks an unaided quint is in the cards. In fact, he says it could even precede the quad axel, a singularly technical four-revolution jump not even Nathan Chen has mastered. The quad axel is the only spinning jump in which the athlete takes off facing forward from the edge of their blade, rather than their toe pick, which lends some much-needed stability at the initiation of a spin. “Once your toe pick’s in the ice, you’re pretty much safe to go up and do your jump,” says Goebel. “But with the axel, if you push too quick, or you’re leaning too far forward, or you’re leaning too far into the curve, you’re going to go right off the side of your blade and instead of rotating vertically, you’re going to rotate horizontally and it’s going to end really, really, badly.”

Which is why Goebel landed a quad in practice before he landed a triple axel, and why he thinks we’ll see a quint before we see a quad axel. It probably won’t happen in the present crop of skaters, or even the next. But in a couple Olympic cycles? “I wouldn’t be surprised if, in six, seven years, you see the best and brightest trying quintuple jumps in competition.”

Leave a Reply

Your email address will not be published. Required fields are marked *