The hardest jump in figure skating is a remarkable achievement on the edge of what’s physically possible. Over the past few decades, the quadruple jump—consisting of four revolutions in the air—has become a dominant force in men’s figure skating. Quadruple jumps have effectively been a requirement for any male figure skater who wants to actually compete ever since the International Skating Union raised the point value of a quad in 2010 (after American Evan Lysacek won Olympic gold that year without attempting a single quad, even though the skater who won silver, Russian Evgeni Plushenko, actually landed one). The jump requires subverting basic survival instincts to spin faster than 400 rotations per minute (the wheels on a car going 60 miles per hour rotate about 800 times per minute) without losing control. “Some kids are a little more amenable to doing that than others—maybe they have less of a sense of self-preservation,” says Jim Richards, a kinesiology professor at the University of Delaware, who uses motion-capture technology to help skaters refine their jumps. The physics of a quadruple jump are fairly straightforward: skaters need to jump with the right combination of lift and spin, orient their bodies properly in the air, and then land gracefully despite impact forces equal to several times their body weight. When working with figure skaters, Richards concentrates on the portion of the jump that happens in the air: how high they jump (ideally, around 20 inches) and how efficiently they contract their bodies to maximize spin rate. More time in the air obviously means more time to spin the necessary 1440°, and body contraction helps thanks to conservation of angular momentum—stuff spins faster when it’s less spread out. There are different types of quadruple jumps, categorized based on their unique takeoffs, but the rotation in the air is basically the same for each. The techniques for the different types vary in difficulty, and are awarded points (pdf) accordingly in all figure-skating competitions. A quadruple toe loop (base score of 10.3 points, though points can be added for extraordinary technique or deducted for bad form) is worth less than a quadruple Salchow (10.5), and a quadruple flip jump (12.3) is worth a full point less than a quadruple Lutz (13.6). For perspective, Japanese skater Yuzuru Hanyu won the 2014 Olympic gold by a margin of less than five points. Between his short and long program, technical-element scores accounted for 145 of Hanyu’s 280 total points. Here’s an interactive visual of the quadruple Lutz, the hardest individual jump that’s ever been landed (American Vincent Zhou just became the first skater to land one at the Olympics). [protected-iframe id=”1b7a5d11ea9e3c2f897ed625ab801813-39587363-96682595″ info=”https://sketchfab.com/models/5be0d46ad0804c62ab322d6c05008e45/embed?autostart=1&transparent=1&ui_controls=0&ui_infos=0″ width=”640″ height=”480″ frameborder=”0″ allowfullscreen=””] Even the world’s best skaters can’t properly land most of their quads—almost two-thirds of jumping passes including quads (a “pass” is comprised of either an individual jump or a combination/sequence of jumps) get point reductions for sloppiness. But losing points is far from the worst possible outcome. Many skaters end up hurt, with anything from sprained ankles to fractured foot bones, shattered knees, and dislocated shoulders. Even American skater Nathan Chen, notorious for doing five quads in his free-skate program, messes up about one-third of his quad passes, according to data collected by SkatingScores. (He dashed his 2018 Olympic aspirations by falling on two quadruple jumps in his short program.) That’s not to mention more chronic issues that result from repeatedly practicing these jumps. Richards has long been concerned that young kids are practicing quads too many times as they work to master them, inflicting incredible stress on their bodies. Richards is particularly troubled by the stiff skates that the athletes use; figure skaters could mitigate the impact of their landings if they could bend their ankles, which would stop all the force of the landing hitting them at once. But, Richards says, manufacturers have no financial incentive to make safer skates. With so many injuries, the current backlash to quads has been unsurprising. Nothing undermines a performance like a nasty fall—especially when it leaves your hero injured and unable to compete—as when Hanyu, the Japanese skater, fell practicing a quadruple Lutz last November and then couldn’t compete for months. That said, there’s no indication that quadruple jumps are going away, even if many people wish they would. There are clear benefits to a scoring system that prioritizes technical aspects like jumps: it makes competitions more transparent, so skaters know what’s required to win. Figure-skating judges are notoriously biased when it comes to evaluating subjective performance, but technical scores are fairly objective. Female skaters may be headed for their own quad revolution. Figure-skating coach Tom Zakrajsek says women are fully capable of quadruple jumps. He should know, as the coach for both Zhou, who just landed the first Olympic quad Lutz, and Mirai Nagasu, the American skater who just became the first woman to land a triple axel at Olympic competition. A triple axel is a jump with three and a half rotations, made especially tricky because skaters enter facing forwards. Zakrajsek said Nagasu is close to landing a quad—she’s done one on a pole harness, a training tool that lets coaches guide their athletes through new jumps. It may be a while before women start attempting quadruple jumps at the Olympic level, though. One challenge is that many women have hips that prevent them from contracting their bodies tightly enough to reach the necessary spin rate. But it may also just be a matter of time: Canadian Kurt Browning landed the first officially ratified quadruple jump in 1988. It took 14 years for a woman, Japanese skater Miki Ando, to do the same. Though Nagasu likely won’t compete at the Olympics (or elsewhere) with a quad jump anytime soon, Zakrajsek says “there are no limits for women.” As for men, some spectators are already starting to speculate about a future where top male figure skaters are competing with quadruple axels, jumps that would involve four and a half rotations, or even quintuple jumps. But that would require even-faster rotation speeds, with even more risk for athletes to lose all control. And given how many fans wish figure skaters would simply go back to triple jumps, it’s not a future many people actually want.