A Horrific Crash. A Mangled Leg. A Crazy Fast Comeback.

You remember Nina O’Brien.

The American Alpine skier tore down the giant slalom course at the Beijing Olympics and crashed in a violent tumble two gates from the finish, leaving her lower left leg and foot twisted in the wrong direction, bone protruding from her skin.

Just nine months after the crash and two months after easing down the gentlest of hills for the first time, O’Brien somehow pushed out of the starting gates in Finland last weekend at the first World Cup races of the season, completing one of two slalom runs. She will do it again and try to improve this weekend at Killington, in Vermont, where most eyes will be on Mikaela Shiffrin, who collected her 75th and 76th World Cup victories on Saturday and Sunday.

For O’Brien, Killington is the next step in a comeback that has stunned even the most optimistic of her coaches and doctors and shown once more that Alpine skiers are different from the rest of us.

“They do say broken bones heal back stronger,” O’Brien said during an interview earlier this month after a day of training north of the Arctic Circle in Finland. “You just never believe it.”

If O’Brien wanted to keep doing the thing she has done since she was a little girl growing up in California, she had to convince herself that her body could be as strong as it was before the crash. Comebacks to competition in skiing are a little different from those in nearly every other sport. They are mind-bending journeys during which there is no such thing as halfway.

A starting pitcher in baseball can ease back to full velocity with some minor league starts. Runners can race at 80 or 90 percent before stepping on the gas. Alpine ski racing requires skiers to careen down scary-steep sheets of ice at 80 miles per hour, and the recipe for safety is borderline irrational but true nevertheless.

“The safest way to ski is aggressively,” O’Brien said.

All O’Brien remembers of the moments before the crash is how fast the last series of gates seemed to be coming at her. Then she was off her skis and felt a twist in her knee. She was sure she had torn her anterior cruciate ligament. Before the pain hit her, she caught a glimpse of her lower leg and saw it was pointing in the wrong direction. She knew instantly it was badly broken.

Coaches and medical technicians surrounded her on the snow. One of them made the smart decision to inject some high-octane painkillers. In an exam room, it took all their strength to remove O’Brien’s super-stiff racing boot. When it came off, they saw her tibia and fibula sticking through her sock.

Just one member of her team, Dr. Jeff Harrison, an orthopedic surgeon and the head physician for the U.S. women’s team, could accompany O’Brien to the hospital, which was outside of the closed Olympic bubble that China had created as part of its zero Covid policy. He conferred with a Chinese surgeon to develop a plan to stabilize her broken tibia, fibula and talus bones so that she could travel back to the United States.

O’Brien awoke after the procedure and found a Medieval-looking metal contraption attached to her shin. She did not have access to the painkilling narcotics she would have received in the United States. For several days, she took only Aleve and Ibuprofen. On the night of her departure, her flight was delayed several hours. She sat in the nearly deserted and frigid airport terminal, her leg aching beyond imagination from hours of being jostled in transit and resting on her ski team duffel bag.

Back in the United States, X-rays revealed that Chinese surgeons had inserted the initial stabilizing pins directly into small fractures in the bone, increasing the risk of infection and requiring a quasi-emergency procedure to remove and replace them. On the bright side, she had not torn her A.C.L. but merely suffered a partial tear of the medial collateral ligament that did not require surgery.

By the next week, the swelling had finally subsided enough for Dr. Tom Hackett and Dr. Randy Viola, surgeons at the Steadman Clinic in Vail, Colo., to try to recreate her pre-injury anatomy.

“The average person, you restore it as close as you can and they never notice it,” Hackett said. For an elite athlete though, every millimeter is crucial.

Because the bones had punctured the skin, damaging tissue and veins, Hackett had assumed O’Brien would face a long recovery. Racing at this level so soon seemed a bit far-fetched. Maybe it’s because she is young, or because of the support she had from physical therapists and coaches, or maybe she was just lucky, he said.

O’Brien had been told the process might take anywhere from six months to two years. She spent five weeks on crutches and another eight weeks wearing a boot.

Before she could think about walking normally, she had to practice using the small muscles in her calf to rotate her foot once again. The idea of pointing her foot and jamming it into a ski boot — a miserable experience for recreational skiers who wear relatively soft and flexible boots but a whole other level of awful for elite ski racers — seemed preposterous.

She returned to Dartmouth, where she attends college in the off-season. She limped around campus, went to physical therapy nearly every day and tried to follow the seven-and-a-half-month “return to snow” timeline that the coaches and physiotherapists with the U.S. ski team had mapped out. First she had to walk without pain, then jog, then jump, and on and on, meeting certain criteria at each step before taking the next one.

O’Brien tried to view the timeline as a series of rough goals and not deadlines. A journey more important than the destination.

“She’s always been tough, and can handle more pain than the normal person, even the normal skier,” said Magnus Andersson, the head technical coach for the U.S. women’s ski team. That made it more vital for him and his colleagues to make sure she rested.

“She won’t rest if she has the choice,” he said.

In mid-September, it was time.

She and Andersson traveled to an indoor ski complex in Belgium with the gentlest of slopes, where she didn’t have to worry about sudden slick or soft patches of snow and a technician was just a few steps away to make equipment adjustments. Within a few runs, she felt like she was skiing again.

“I didn’t cry,” she said. “I just felt stupidly giddy.”

Within a few days, O’Brien was linking quick turns again. By the end of the week, Andersson thought she was skiing better than she had before the crash. In October, she traveled to Austria to rejoin her teammates. Before long, she was chasing speed again, just like they were. She would have raced at the season-opening competition in Soelden, Austria, last month, but it was canceled.

“We all want it so badly,” she said. “We all want to go fast.”

Every morning, she wakes up and spends a few moments taking the measure of her leg. After nearly every run she thinks, How does my shin feel? Do I have pain in my knee?

In a training run on the back side of a glacier in Austria, on a cloudy day last month, O’Brien put a little too much pressure on the inside edge of her ski, went down hard on her hip and slid into some soft snow. She’d been going fast.

Her first fall with her new, old leg was out of the way. She was fine.