Mark McMorris stood atop the big air snowboard jump at dusk. It was a Sunday, last February, during the semi-finals of an Air + Style contest. An almost-full moon floated above the horizon. The jump, built on scaffolding near downtown Los Angeles, was about 14 storeys high.

At 22, the Regina native was in the middle of an excellent winter; already a snowboard star for five years, he had been chosen snowboarder of the year by the sport's two leading magazines.

Big air, which makes its debut at the Winter Olympics next year in Pyeongchang, South Korea, was one of McMorris's specialties. He had planned a difficult trick involving three off-axis flips and four rotations of 360 degrees. It was the trick that scared him the most. He turned his board down the 42-degree slope of the jump – a grade rated double black diamond on ski hills.

After spinning and sailing 30 metres through the air, McMorris landed hard and fell on his backside. Two seconds later, he caught an edge on the bumpy landing. His body crumpled, and the forces collapsed on his right leg. His femur – the largest and strongest bone in the body, connecting the hip to the knee – snapped.

In an instant, he flipped over, spun on his back and slid to a stop. He screamed in pain. He knew exactly what was wrong – and how long it would take to get better. His season was over, and the next winter, ahead of the Olympics, was crucial. Fighting back from the worst injury of his career, he would have to prove himself all over again among the world's top snowboarders.

Behind McMorris's rehabilitation, there was a lot at stake. His primary backers are two of the biggest names in action sports: Red Bull, one of the world's top beverage brands, and Burton Snowboards, the sport's leading company.

For Burton, McMorris is the bright young light in an industry where sales and participation are in decline after years of rapid growth. For Red Bull, which paid for McMorris's medical care, the snowboarder is part of the machine that sells six billion cans of energy drink each year; the brand's value is underpinned by the exploits of athletes hurling themselves into space – athletes like Mark McMorris.

An old soul

A week after the crash and surgery, McMorris welcomed Jake Burton Carpenter to his home south of Los Angeles.

McMorris had been barely able to sleep and didn't move much. Painkillers muddied his dreams during the little rest he got.

"A lot of the times I'd just be running away or running somewhere," McMorris recalled. "When I'd wake up, I'd be like, 'What?' – and then feel my leg start throbbing."

Carpenter, in his early sixties, is the patriarch of snowboarding. He founded Burton in 1977. Through the decades he has been a benefactor, mentor and friend to the sport's best – stars such as Craig Kelly and Shaun White.

Carpenter and McMorris have forged an especially close bond.

In 2015, Carpenter was felled by Miller Fisher syndrome, a nerve disease that caused almost complete paralysis. McMorris was by his side through a long, arduous convalescence.

"When Mark walked in the room, he just lit it up," Carpenter said. "Others almost were in tears, I looked so bad."

He described McMorris as an old soul.

"When you look at Mark, he's a kid that came out of the flattest part of the world and made himself a world-class snowboarder. I would do anything for that kid, really," Carpenter said. "He saw me come back – from talking to my kids about suicide. I've showed him how low you can go and still come back."

Canada, for all its mountains, has never produced a more successful snowboarder than McMorris. At 18, in early 2012, he began his winning spree at the Winter X Games. In 2014, at the Sochi Winter Olympics, he won a bronze – just two weeks after he broke a rib at the X Games.

His buoyant, easygoing personality – and resilience on the mountain – made him a fan favourite.

He has since starred in his own snowboarding movie. A video game, Mark McMorris Infinite Air, came out last fall. On Instagram, he has 534,000 followers. And while snowboarding remains a niche sport, McMorris emits a broader cool than the typical Canadian athlete. Last summer, when he had again been nominated for an ESPY Award in the best male action sports athlete category, Prime Minister Justin Trudeau tweeted: "Keep representing Canada as stylishly as you do." McMorris responded: "Appreciate the support my dude."

Surgery

His surgery took place at the Keck Hospital of USC in Los Angeles the day after the crash. The break was transverse – a relatively clear crack across the bone. There was no damage to the hip or knee.

"It's lucky is what it is," said Seth Gamradt, a sports doctor at USC who co-ordinated the surgery.

Geoffrey Marecek, a specialist in fracture trauma surgeries, led the work. An incision was made below the hip on McMorris's right buttock. Two more small incisions were made at the break point to insert small hooks and align the femur.

A device called a reamer was run through the middle of the femur – the medullary cavity – to smooth it. A titanium intramedullary nail, about a centimetre in diameter, was then inserted. Two screws near the hip and two near the knee fixed the nail in place.

A femur typically heals in three months, and patients return to a regular routine by six months. Complete recovery, however, takes longer.

"For anyone," Marecek said, "it's going to take a year to be at the best you're going to be."

Mid-March

McMorris hobbled in on crutches. It was his fourth day of rehabilitation at the Fortius Sport & Health centre in Burnaby, B.C.

His program was guided by a director at the centre, physiotherapist Damien Moroney. They had worked together since McMorris's first gold medals at the X Games. The plan was to rebuild strength and restore movement so the break would eventually leave no trace beyond the small scars.

The daily sessions lasted three or four hours. McMorris started on a stationary bike.

A massage followed. Moroney worked on the injured right leg with a therapy known as myofascial release – to loosen the quadriceps and stimulate blood flow. When the body suffers trauma, Moroney explained, it doesn't heal in an optimal way – with the muscles contracting to serve as a kind of cast. "You have to tell the body what its role is and what it's supposed to do," Moroney said.

Later, McMorris was on his back on a leg-press machine.

"Keep the pelvis still," Moroney said. "Think of the pelvis as an anchor."

McMorris's eyes narrowed, like he was readying for a snowboarding contest. "Oh my God," he said after a series of light reps. "It's just intense. It doesn't feel like it'll support it."

Soon after, he was up to his chest in water. The machine was an underwater treadmill called a HydroWorx. A spongy platform submerges, and the patient is buoyed by the water – allowing him to walk well before actual walking is possible.

McMorris stepped along at 1.5 miles an hour. "New world record," he said with a laugh. On his first day, he managed only one mile an hour and had to hold a railing. "It feels so nuts to be walking."

Back out of the water, reality returned. "It's gnarly when you stop," he said. "Oh, my leg is still broken."

He reached for his crutches. "I just wish I didn't have these things. These really bum me out."

Early April

The usual swirl of McMorris's work and life had slowed. "I'm never anywhere for three weeks," he said, eating breakfast near downtown Vancouver. "It's nice to go to the same coffee shop every day."

The crutches were gone. He wanted a "badass" cane, so he talked to Greg Dacyshyn, Burton's chief creative officer, who sent him a sleek wooden cane with a bone handle.

"Mark is the prototype of what we look for in a rider," Dacyshyn said. "Works incredibly hard and is very humble. And he wants to do things that haven't been done before."

Back at the Fortius centre, McMorris and Moroney worked through exercises. McMorris walked up a set of 28 stairs – without the cane. "Can't stop the kid," Moroney said encouragingly.

"I'm feeling a lot more like a human," McMorris said. "It's sweet."

In the HydroWorx pool, his progress was measurable: He twice jogged a half-mile at 4.5 miles an hour.

Then came the cold pool. Research suggests the optimal time and temperature for muscle recovery is about 12 minutes at 12C.

"It's so cold," McMorris said, dipping in.

"Oh, you love it," Moroney joked.

McMorris laughed. "I hate it."

Late April

A turning point. Downtown, near his apartment, McMorris started to cross the street when the light turned yellow. He jogged the rest of the way. It wasn't much, but it felt like a lot.

The end of May

At Fortius at 10 a.m., back on the stationary bike – three months and a week since the crash.

"It feels," McMorris said, "like it's been for-ev-ver. I'm way ahead of schedule for a femur but I know I'm not remotely close to snowboarding like I can."

But a sense of normalcy had returned. He'd been on the move, out east for Burton work and Carpenter's birthday and west for more work. At a photo shoot at Mammoth Mountain in California, he made a few hesitant turns on a snowboard in some slushy snow. "I was so happy," he said. "And I realized how much more I needed to do."

In San Francisco, shooting a Burton video, he was greeted outside an Amoeba Music store by Danny Davis, who several years ago had recovered from a more complicated broken femur.

"A couple months into a femur break and he's just rolling – no crutches, no cane, no nothing," said an impressed Davis.

Back at Fortius, McMorris did a session on force plates, an array of square measuring instruments on the floor. Sean Mc Keown, a strength coach, instructed McMorris in a series of jumps. On the adjacent computer screen, lines indicated the power output. His left and right legs were even at the start, but then the right leg was shown to be weaker.

The challenge was in the vastus medialis, the inner thigh that connects with the knee. It helps channel power from the hips to the feet. The femur was almost healed. Rebuilding the muscle would take longer.

"It just dies," Mc Keown said to McMorris, pointing at the screen. "There's nothing there."

There were still spikes of pain. "This metallic thing," as McMorris described the feeling in the back of his right knee when squatting. "The screws and everything makes this so foreign."

The end of June

It was sunny, breezy and quiet at the Ambleside Skatepark near the water in West Vancouver. McMorris booted around on his skateboard with restrained ease. On a two-sided quarter ramp, he rode up, ollied into the air and over the top, then landed and rode away, pushing with his recovering right leg.

He was 9 when he landed his first sponsorship from a local skateboard shop. "Super young – got lucky," he said.

His femur was solid again. He stumbled on one trick. "It'll get better."

Late July

McMorris, back in Vancouver after the ESPYs, showed off for Moroney at Fortius: a standing backflip.

"I just wanted to show Damien I could do one again," he said.

Moroney then arranged several large blocks for standing jumps. McMorris leaped up 85 centimetres, two blocks high. He bounced down to a lower block and spun 180 degrees as he jumped back to the floor. After a series of these, Moroney rearranged the blocks.

"Can you make it?" he asked McMorris of the new 110-centimetre height.

"No problem," McMorris said.

He jumped up five times. On the last two, he spun 360 degrees as he jumped off.

"I finally feel like myself again," he said.

In a week, he would fly south – for the winter. New Zealand was up first – a week for a Burton catalogue shoot – then to Australia in mid-August. The Perisher Valley, five hours south of Sydney, is an off-season training destination for pro riders, with big jumps. It was where McMorris would first truly test himself since the crash.

Rehab, Moroney said, is as much mental as physical – rebuilding confidence is almost more challenging than rebuilding muscle. Outwardly, McMorris was poised – but doubts floated through his head. He couldn't help but wonder if he could be the same snowboarder he had been before he crashed in L.A.

Half a year

On a Thursday in late August, six months and three days since the surgery, McMorris popped a series of jumps at Perisher. First, a smooth 720-degree spin with a tail grab. Off the second jump, he arched an easy 180. Riding backward up and off the third jump, he spun 900 degrees – 21/2 times around.

"Missed this feeling!!!" he posted on Instagram.

Four days later, he was going notably bigger – a double-cork 1080, two off-axis flips, three spins with a mute-to-tail grab, two hands on the board. The work in rehab had paid off; he was quickly coming into form.

"Sometimes you have to grunt it out," he wrote on Instagram. "Stoked to get this one back."

The start of winter

Training on a glacier in Austria, south of Innsbruck, McMorris was ready. His calendar was busy with a series of events before Christmas and then the big ones thereafter.

Winter X Games in Aspen, Colo., where he first made his name, were coming up in late January and the Olympics would be only a year away.

He had unfinished business. He savoured the Olympic bronze medal he won in slopestyle in 2014 in Sochi after rallying so quickly from the broken rib. But he was still chasing the gold. In Pyeongchang in February, 2018, McMorris will have two shots at it – in slopestyle and big air.

His right leg was solid. He didn't think about it any more.

"Obviously, going into competition, it's a little psychy. Scared – a little bit," he said by phone from Austria. "Not scared about anything injury-wise. I just want to come back and win everything, be like I was when I left off. That's always a little nerve-racking."

He paused.

"I'm pretty excited, too, you know?"

In his return to competition, at a big air event in Milan, he was third. Then, at an Air + Style in Beijing, he was first going into the finals but finished fifth.

It all came together in South Korea in late November, at the big-air test event ahead of the Olympics. McMorris won. It was the first time since his crash that he tried the trick that went so awry in L.A., a frontside triple-cork 1440. It was the one that always scared him. The rider flies half-blind through the air and has barely any time to spot the landing. McMorris nailed it.

In a video for ESPN, shot earlier in the fall, McMorris skateboards through the streets of New York City. In a voiceover, he speaks about the pressure at contests, standing at the top of a run – his legs turning to butterscotch pudding. His mind quiets. The dogma of positive thinking carries him. His voiceover chimes: "You create your destiny."

In early December, the contest tour was in Breckenridge, Colo., for a modified two-day slopestyle event. McMorris won it and was joined on the podium by Canadians Max Parrot in second and Sébastien Toutant in third.

The first day, Dec. 9, was McMorris's 23rd birthday. There was a pounding snowstorm. McMorris landed another frontside triple-cork 1440, with the snow swirling and the sky a thick grey – difficult to distinguish from the ground. "You are officially back," an interviewer declared.

McMorris was ecstatic. It was a birthday present to himself.

"I'm super-amped."