If anyone could have completed a quadruple axel at the Beijing 2022 Winter Olympics, it would have been Hanyu, says Sarah Ridge, a biomechanist at Brigham Young University. “The thing about him is that he’s built for this perfectly”—and has the skills and talent to match. Landing the quadruple axel in the future, she adds, is not out of the question for Hanyu. A quadruple jump requires a grueling four full revolutions in the air. The axel, the only figure skating jump that involves taking off facing forward and then landing backward, elevates the challenge, demanding skaters tack on an additional half revolution to their mighty vault. According to The Washington Post, 2022 Olympics men’s figure skating gold medallist Nathan Chen mastered all the quadruple jumps except for the axel. A sequence of complicated events needs to occur for a skater to complete any spinning jump on the ice. Before they take the leap, the contender creates rotational momentum while on solid ground, by extending the limbs and twisting the body like a preloaded spring. Then, they must propel into the air. (The higher they jump, the more time they spend aloft.) Once airborne, the skater snaps into a ramrod straight position, tucking the arms and legs into the center of the body and axis of rotation. This reduces the body’s moment of inertia, or resistance to spinning, and speeds up the rotation. Upon landing, they once again spread out their limbs to increase the moment of inertia and essentially halt rotation, all the while keeping balance on a razor-thin blade. It’s an astonishing amount of physical changes and decision making packed into a split second. The margin of error gets even smaller when an athlete tries to stitch more revolutions into a seamless stunt, says Deborah King, a biomechanist at Ithaca College. Given the limited air time, skaters need to reach their maximum rotational speed as soon as they leave the ice to finish their target revolutions. Once they’re at top speed, they must hold their body positions and whirl away for as long as possible, right up until the landing. For now, no female or male figure skater has broken the upper limits of four spins, or a quadruple. That puts four-and-a-half revolutions, or a quadruple axel, tantalizingly within reach, says Ridge. But is it possible to push beyond that number? The Olympics motto—faster, higher, stronger—adds another ideal when it comes to skating: lighter. King says that the maximum number of rotations possible is limited by the figure skater’s moment of inertia, which in turn is dependent on body mass and shape. A slight constitution naturally gives them the advantage of a low rotational resistance. But no matter how much an athlete contracts and elongates their bodies during a jump, they can only squeeze as small as the width of their shoulders and hips, King explains. “If you watch a skater when they jump and you look at their position in the air while they’re doing quads, they’re already pretty much as small as they can get,” she says. Another requirement is that figure skaters need to be strong, without the cost of increasing muscle mass. (Hanyu himself only weighs about 125 pounds and stands 5 foot 8 inches tall.) More strength translates to higher jumps and the ability to hold the body tightly while spinning in the air—an exhausting process despite how easy the pros make it look. The faster a skater spins, the more centrifugal force acts on their limbs, causing them to fling away from the body and out of the ideal rotational form. In some sequences, the twirler might feel a force of up to one-and-a-half times their body weight on their arms. Still, there’s only so fast an athlete can spin, and there’s only so high they can jump. “You can’t put all your effort into rotating; you can’t put all your effort into jumping. There’s a fine balance,” says King. Figure skaters typically hover in the air for about half a second, but hardly more than that, she says. With that math, she thinks five revolutions is probably the highest number of spins possible. Six spins or higher is nearly unfathomable. “I really cannot see that happening,” she says, “I would love to be proven wrong.” Other experts agree that a quintuple jump might be the most spins that the sport can dream for. Ridge herself has measured the spinning rate of top American figure skating athletes. Even for those topping 2,000 degrees per second, the highest measurable range of Ridge’s instruments, she doesn’t expect anything higher than five revolutions in a single jump. “Maybe it is possible, and I just don’t have enough imagination,” she notes. The only way the number would be beaten, Ridge says, is with a drastic revamp in ice skating equipment to allow athletes to better harness their motion for stunts. But given that skaters only have their boots and blades to work with, there’s not a lot of wiggle room to engineer a way into a more impressive feat. Mirai Nagasu, the first American female figure skater to land a triple axel at the Olympics back in 2018, also thinks a quintuple is within the realm of possibility. She says younger athletes like “quad god” Ilia Malinin will be inspired by the record-breaking achievements of current skaters to push the boundaries of the sport in the years to come. But landing new feats only counts if it can be done safely, she adds. “We need more protection for these young athletes who are pushing their bodies because they want to win so badly,” Nagasu says. While learning the triple axel, she tore her lower labrum and had to undergo multiple hip surgeries. Breaking records in the sport may not be worth it, she says, if figure skaters exchange a heartbeat of glory for a lifetime of physical pain. As much as the public delights in thrilling new athletic displays, in the end, it takes Olympians many sacrifices to make the impossible possible. Correction (February 14, 2022): The story previously stated that centripetal force causes a skater’s limbs to push away from their body as they spin. It should be centrifugal force.