CHULA VISTA, Calif. — Twice a week they would sprint on their bikes through the park down the street, each burning to beat an invisible time that ticked furiously against them. Whenever Sam Willoughby had a good day, his fiancee, Alise, did too. They always seemed connected that way.

They were young and fast and just about the best BMX bike racers in the world, each with an Olympic silver medal — his for Australia, hers for the United States — and certain that one day each of them would win gold.

But that was five years ago, before the day Sam’s bike flipped on the practice track at the Olympic Training Center, before the helicopter flew him to the hospital in San Diego, before the five hours of surgery, before the doctor said the words “permanent paralysis” and their dreams of each winning gold became their dreams of just her winning gold.

Now Sam parks his wheelchair on a path beside one of the other tracks at that same training center, watching with a timer in his hand as Alise races down the starting ramp. In the years since the accident, they got married, he became her coach, and she won a world championship. Instead of racing on the same day as Alise at the Tokyo Olympics, he will sit beside her in the pit.

“She’s better at this than I am and a better athlete than I was,” he says, glancing between the track and his phone. “Her strength in racing is, like, she can show up and she’s the calmest person in chaos.”

A few hundred yards behind him is the track where he was hurt, the one Alise calls “the elephant in the room.” They practice on it all the time, Sam watching Alise ride over the exact spot where he wrecked, knowing it is there but never acknowledging its presence. It stands as a silent reminder of how much they’ve been through, how much they’ve survived and how much has changed.

They can’t escape the past even if they want to. Alise is 30, and Sam turns 30 in August. Their entire adult lives have been built around the training center’s tracks, and they even live in the same house as before — the one two miles across the highway with the stucco walls and the words “I kiss better than I cook” painted above the kitchen stove.

Those bike sprints at the nearby park are some of Sam’s favorite memories. He loved the way they would tease each other by holding their times secret and then revealing them with big laughs. The best part wasn’t the winning but the days spent chasing it. That’s why he started coaching Alise, why he still comes to the training center every day, why he sits beside the elephant in the room and pretends nothing happened there.

“Our strengths and weaknesses kind of complement each other,” he says.

Then he presses a button on a motorized handlebar attached to his wheelchair. A motor whirs, and the chair jolts and hums down the dirt path. A plume of dust flies up behind the tires.

A small world

It started with a crush.

Back when he was 11 and a rising BMX racer in Adelaide, Australia, Sam was watching DVDs of championship BMX races in the United States when he noticed a girl his age. She wore a choker necklace. “She’s cute,” he remembers thinking. The DVD said her name was Alise Post and she was from St. Cloud, Minn. He wondered if they would ever meet.

BMX racing is a small world, and soon they were both among their countries’ top teenage racers, making national teams and flying to the same international competitions. At a 2006 race in Brazil, a friend introduced them. She had never heard of Sam Willoughby. He knew exactly who she was.

They talked again the next year at a world championship in China and kept talking even after returning home. A few months later, Sam told Alise he wanted to train in the United States. She asked him to come to Minnesota, then told her parents a boy she knew from Australia was coming to live with them.

“She said he was just a friend,” her father, Mark Post, says now. “But here comes this Australian boy with a big smile on his face when I open the door, and I’m saying, ‘Yeah, riiiiight.’ ”

Soon they were dating, and they fell in love. When Alise went to college at the University of San Diego, Sam followed her to California. They rented an apartment together, and a few years later they bought their house.

They went together to the 2012 Olympics in London, where Sam won silver and Alise crashed in the medal race. When Alise’s mother, Cheryl, died in January 2014, just months after being diagnosed with Stage 4 melanoma, Sam was almost as distraught as Alise. They both raced with Cheryl’s name on their bikes.

They got engaged a year before the 2016 Olympics in Rio de Janeiro, planning their wedding for the following spring. Sam went to Rio as one of Australia’s best gold medal hopes. But it turned out to be Alise who won in Rio, taking silver, while Sam — trying to ride on a torn ACL — finished sixth.

Afterward, she went back to Minnesota to celebrate and help run a charity race. Sam stayed in Chula Vista, hoping to understand what had gone wrong with his riding.

Everything changed

Sam remembers everything about Sept. 10, 2016.

He remembers how he went to the track for a casual workout, how distracted he was with his knee and the Rio finish, how he was just warming up when he rode into the row of small jumps called “the rhythm section” too much on his back wheel, how his bike flipped upside down in the air, how he landed on the top of his head, how when he hit the ground he could see his legs and it was as if they were somewhere in the distance, too far for him to reach.

He remembers it was a Saturday morning and there were several kids around the track. One of the kids’ fathers happened to be an EMT, and the father touched Sam’s toes, then his legs and then his chest. And each time the father touched him, Sam felt like he was wearing a wet suit filled with water.

He remembers the ambulance arriving and the paramedics worrying that the road was too bumpy and his back too unstable, so a helicopter was summoned. He sat alone in the back of an ambulance, waiting for the helicopter that would take him to the hospital in San Diego, and all he could think was how helpless he was going to become, what a burden he would be and how he had just taken his last ride on a BMX bike.

By the time Alise, who flew in from Minneapolis, got to the hospital that night, Sam was waking up from surgery. The doctor told him he had broken the C5, C6 and C7 bones on his vertebrae and that he would never walk again. She stood beside his bed, her hand on top of his, and they both remember Sam looking at her and saying: “You aren’t marrying me. You aren’t marrying a vegetable.”

He regrets that word now. Vegetable. But in that moment he didn’t have the vocabulary for what he felt. All he could think about was the 25-year-old woman, an Olympic silver medalist, standing beside his bed and how her life was going to be spent pushing him around — and how he couldn’t stand to do that to her.

Sitting in their kitchen now, Alise goes silent.

“Yeah,” she finally says. “That wasn’t good.”

“What do you say to that?” Alise continues. “I know what he was going through. … That’s going to be what his response is going to be, you know, like, ‘I need to not be a burden on anyone and push everyone away.’ ”

She told herself she would be strong for Sam, that she would remind him that he was the same person as before the accident, that their engagement meant they would stay together no matter what. They moved to a rehabilitation hospital in Colorado. She barely left his room.

They came home to Chula Vista on New Year’s Day of 2017, but the return was not happy. Sam hated that they had to install an elevator so he could get upstairs to their bedroom and that he could no longer reach things on the kitchen shelf. He refused to go out to dinner, worried about how he would get to the bathroom. He became obsessed with walking again, certain that would solve everything, determined to be standing when they got married. Some days, he only got out of bed for therapy. They postponed the wedding.

Alise kept falling during her practice runs. She could tell her mind wasn’t on racing. She split with her coach and dropped out of races. She began to think about quitting BMX.

But leaving Sam was never an option. One day, she snapped at Sam, shouting, “If my dad could have my mom back alive in a wheelchair, I know what he’d do to have that!”

The memory still makes her cry.

“My mom was just 53 when she passed away, and it all happened in like nine months,” she says. “And my dad, you know, he didn’t sign up for that, either. …Nobody signs up for the stuff, but they’re there for the person and everything else, like, and it’s like I don’t know how to explain it, but [there’s] never enough time. Why would I cut that time short?”

Getting on with it

Sam’s brother, Matt, flew up from Australia to help. Knowing Sam loved car racing, Matt called a friend of Sam’s who worked for NASCAR and got passes for a race in Fontana, Calif. He needed something to get Sam out of the house. The friend introduced them to some drivers, including Jimmie Johnson, Richard Petty and Kasey Kahne. Then the friend took them to meet Bootie Barker, a crew chief who was in a wheelchair, too. Sam told Barker that he was working to walk again.

“Cool! That’s great!” Sam remembers Barker saying. “Then what?”

Sam was silent. He didn’t know.

So, Barker talked. He said that when he was paralyzed in a car accident, he “didn’t do no rehab,” leaving the hospital on the day he could put on his shoes, which was three weeks after he came in. He didn’t change his house or buy special furniture. When he goes to bed, he climbs up onto his mattress and “fights it every night.”

“You got to get on with it, brother,” he said.

And right there in the trailer, something changed for Sam.

“I had this newfound motivation to be independent,” Sam says. “And it was just something that clicked. For the first time, I met someone [who’s] actually living [life] and was giving me this whole new world of advice of: ‘Just do whatever you want; try it and find a way.’ ”

A few weeks after meeting Barker, Sam raised the idea of coaching Alise. It was something he had been thinking about even before the accident. He has always had an analytical mind, spending hours watching video of their races and breaking down data in detailed lists on his computer. But Barker’s words kept ringing in his head. He needed something to do. He needed a purpose. Perhaps, he thought, that could be it.

They started training — Sam as the coach and Alise as the racer. On New Year’s Eve, a year after coming home from the hospital in Denver, Sam and Alise were married. That night, with help from several of his friends holding his arms, Sam stood up and even took a few halting steps.

A new vision

Lately, Sam has had this dream where he is in his wheelchair at the starting gate of a big race. As the gate drops, he’s suddenly transferred onto a bike, pedaling furiously, feeling every jump and turn until he crosses the finish line and goes back into his chair.

He isn’t sure what the dream means. For the first few years after the accident, he had a lot of dreams in which he was walking. To Alise, it’s clear he sees himself differently now, understanding that he has “ticked all the boxes” in his riding career and is moving on to something else.

He doesn’t miss being on a bike, but sometimes at big events, when the lights go off before the main races and the air fills with anticipation, he longs for the rush that comes when the gate drops. He still gets some of that from coaching Alise and the handful of other riders he has started to train, but there’s that control from being in the race itself that he can’t duplicate.

So he competes how he can, doing everything for Alise the way Barker does for his NASCAR teams. He drives her equipment to the training center, sets her schedule and makes her lunch. When the pandemic hit and their gym closed, he ordered weight equipment and turned their garage into a gym. A pair of 100-pound dumbbells rest on the ground. Those are his, a gift from Alise.

Her workouts now are harder than they were before, but Sam has a reason. Nine out of 10 BMX races are won at the bottom of the starting ramp, he says. Whoever has the lead going into the first set of bumps can usually control the race. Passing is hard. At 5-foot-2 and 125 pounds, Alise is smaller than most riders, and the only way to match their size is to build muscle.

“Momentum is your friend,” she says.

Today’s session will go for almost two hours into the late afternoon. By then, Alise will have pulled the two stationary bikes into the driveway, lifted 90 pounds of free weights and jumped from a standstill onto a three-foot pile of pads. She will be tired. Her legs will hurt.

But as the sun falls, lighting the hills around them, they will fall into a sweet, silent rhythm, neither of them needing to say a word. They are a husband and a wife working for the same purpose in a love story that didn’t turn out the way they thought but is perfect just the same.