Mirai Nagasu’s Jumps Defy Physics—and Pummel Her Body
Skaters make it look easy, but lifting off and spinning three-and-a-half times is brutal on the body—we just don't know how yet.
Mirai Nagasu’s zippy triple axel made her the first woman in American figure skating history to land the jump in Olympic competition. Nathan Chen makes quadruple jumps look as easy as spinning a top with a flick of a wrist.
However you call it—jump, loop, or axel—the visual of a skater spinning through the air is trademark Winter Olympics fare, when we all join commentators every four years in analyzing how many times a figure skater swivels in midair, grimacing in the split second before they either land triumphantly on the ice or topple over and take a tumble.
But how these gravity-defying jumps actually affect the human body remains a bit of a mystery. Deborah King is a professor in exercise and sport science at Ithaca College, and she’s studied the biomechanics of ice skating for about a decade. She’s also written what’s perhaps the most definitive study of the biomechanics of triple and quadruple jumps.
Still, King says we don’t really know much about how jumps affect the body, though we have some faint clues. “Long term, we know that figure skaters have fairly prevalent overuse injuries,” she told The Daily Beast. “But we don’t really know the impacts and stress on [figure skaters’] bodies.”
That’s because launching a body into the air to garner technical points only became important after a July 1990 change in judging that essentially demoted the “figure” part of figure skating, which referred to making etches in ice based on how the blade tilted on a skater’s boot. Until then, judges awarded points based on how a skater could glide across ice and essentially make patterns; the more intricate and clean, the better their points. That meant the artistry of skating often came down to a more balletic dance routine that was objective and led to accusations of cheating and unfair judging, along with the more salient fact that it made for bland, mind-numbing television.
The 1990 World Championships were figures’ last hurrah, and instantaneously, the sport changed, with points and wins favoring jumps. “When figure skaters stopped skating figures, they started doing free skates and short programs, and that means they have to train more in technical spins and footwork,” King said. “The skills that are high demand are more stressful, and put a lot of demand on bodies.”
As Deadspin pointed out last year, the judging change immediately, radically transformed how skaters were awarded points, making the sport more rigorous and athletic with its higher valuation on jumps. Kristi Yamaguchi nailed a gold in the very next Olympics (1992, in Albertville) with a meteoric rise to the top that was attributable to the fact that she wasn’t great at figures, but could nail jumps and spins.
The movie I, Tonya showcases the fundamental rift that occurred after judging changed, with Nancy Kerrigan’s artistry, beauty, and grace pitted against Tonya Harding’s more difficult leaps into the air. (Prior to Mirai Nagasu’s landing the triple axel on Sunday night in the team competition at the Olympics, Harding had tried, nailing it at the 1991 U.S. Figure Skating championships but unable to repeat it at the 1992 Albertville Olympics, where Yamaguchi scored gold.)
What makes the triple axel so difficult to land—and why Nagasu is only the third woman in Olympic history to stick it—is the momentum it takes to launch a skater into the air, spin three-and-a-half times in about a second, and land on one gliding skate, and also the hard landing, which does a number on the skater’s joints.
“In the singles events, there’s knee injuries, tendinitis, stress fractures,” King ticked off. The seeming effortlessness and grace of lifting oneself off to spin a few times midair is part of the magic; as the University of Manitoba’s sports biomechanics department points out, the more rotations desired, the higher the jump necessary, the deeper the knee flexion, or the dip in the knee before a skater lifts off.
Jumping in the air takes a lot of vertical velocity, which means coming back down leads to a lot of pressure on joints, King said. And that’s only once; the more a skater jumps and lands (skaters can easily do more than 60 jumps a day as they train, according to King), the more pressure they are putting on their joints, the more likely they’re going to get irritated and suffer from “overuse injuries.”
“Overuse injuries come from too much load and not enough recovery time,” King said. “You can get into a cycle where [muscles] continues to break down, particularly in the knee, lower leg, ankle, and foot.”
But King and her fellow exercise physiologists have been unable to figure out exactly what happens to a body as it undergoes the immense stress of landing jumps and quads. King is currently trying to measure impact loads—or the shock the leg and foot are taking when they land—by placing sensors under the boot and around the leg. King is also studying skaters in her laboratory, having them simulate landings onto “force plates,” which measure how much force skaters are landing with.
That’s important, because as of now, it’s an unknown quantity, so we don’t quite know how much pressure is being put on skater joints. King said that while some researchers have tried to estimate that statistic with motion data and calculating it as a ratio of the speed and weight of the skater, it’s still a range.
“Generally, the sport [has gotten to the point] where almost every male in the top 12 will be doing quads, some more than others,” she said. For those skaters—Nathan Chen has previously landed five quadruple jumps, Vincent Zhou was the first junior to land a quadruple jump—that means the force is going to be between five and eight times the person’s body weight.
That’s huge. Take Mirai Nagasu, who comes in at 125 pounds. Landing that triple axel means that the amount of force she’s coming down with is between 625 and 1,000 pounds. That’s up to a half a ton of weight that Nagasu is coming down with as she lands. With men, “they’re carrying more energy through jumps and larger forces”—making the pressures that Chen and Zhou are potentially placing on their bodies that much more forceful. But that shouldn’t take away from Nagasu’s ability to do the triple axel and its rarity: Women have a harder time having the mass and power to defy gravity and whip around in the air, which means she had to really train. As Nagasu mentions in the video below, “I had to put my butt pads in so I could take the falls.”
What’s more, Nagasu is coming down with that much weight on her frame on a single foot, over and over again. That makes skating’s jumps that much harder on the body, King said: “It’s the same foot and leg taking all the force.”
That’s a lot of pressure Nagasu is putting her body through, which means many skaters at her level are looking for a way to ease the pressure they’re putting on their bodies. Nagasu’s use of kiniseo tape (mistaken by many Olympics fans as a thigh tattoo) could ease things—or just be a placebo, King said, noting that the research isn’t quite there yet.
“The likelihood that it lessens the force going up the body are slim,” she said. “Where the benefits are coming from are not known.” King surmised that kineseo tape helps skaters like Nagasu be “more aware of how they’re using their muscles and body and technique”—maybe bending their knees when their skates touch ice to soften the landing, or using a bigger range of motion to allow powerful jumpers like Chen to use a bigger range of motion before hurtling themselves through the air.
King emphasized that there is still a lot of research to be done not only in understanding what a skater’s body is going through as they fling themselves against the laws of gravity but also understanding the long-term effects, especially because the rule change in skating that favored jumps was so recent. “Are they going to have higher incidences of arthritis? Are they going to get joint replacements at a younger age for wear and tear? We don’t know that yet,” King said. “We see these in a few skaters but we don’t know necessarily yet. If the International Skating Union wants to understand impact loads on the body, then we have to understand these [jumping] skills and how skaters train.”