Canada's top track and field athletes are vying for a chance to compete at the 2016 Olympics during trials in Edmonton this weekend.

But for every athlete who makes the team, there are dozens who won't get the times, distances, and heights they need to qualify. Among them, senior track stars on their final bid for Olympic gold.

For Jen Cotten the road to Rio ended on Friday when she placed fifth in her 400-meter hurdle event. Each of the four women who finished before Cotten qualified for the Olympics.

Jen Cotten narrowly missed her chance to compete as a 400m hurdler at the 2016 Olympics in Rio. (Zoe Todd/CBC) "It's a lot more broken dreams than dreams that are made," Cotten said about the track and field trials. "Putting yourself out there is not easy."

Cotten grew up as a 'military brat,' constantly moving between Canadian cities. She says athletics remained steadfast in her life, even when her family moved to small towns without competitive track teams.

During her university years, Cotten trained and competed as a heptathlete in a seven-event contest comprised of 100-meter hurdles, high jump, shot put, long jump, javelin, as well as a 200-meter and an 800-meter run.

It's a lot more broken dreams, than dreams that are made. - Jen Cotten

Cotten transitioned to 400-meter hurdles after university because, she said, her performance in running and jumping consistently outranked her ability to 'throw things.'

After failing to qualify as a hurdler for the 2016 Olympics, the 28-year-old said she's reevaluating her dedication to elite sport.

"It can be the lowest of lows and the highest of highs," she said,

"This is a small part of my life that will play out in the bigger scheme of my life. Even if I step away from athletics, I'm still an athlete at heart — competitive and driven. I look forward to applying 'me' to the rest of my life."

Cotten isn't the only senior athlete waking up from Olympic dreams.

Canadian heptathlete Jillian Drouin says she plans to retire after missing her chance at competing in the 2016 Olympics during trials in Edmonton. (Zoe Todd/CBC)

Jillian Drouin and Natasha Jackson contended for a chance to represent Canada as heptathletes.

Neither made the cut.

"I've done all that I can to prep for this moment, I've put everything I can into the exact moment," Drouin said. "All you can do is walk away knowing you've done everything that you can. It doesn't always take away the whole sting of disappointment."

Obviously not everyone can be a winner. - Jillian Drouin

Drouin, 29, who works part-time as a chiropractor, said she can feel the end of her athletic career looming. But the prospect of retiring from elite competition, and the pressures that come with it, is rekindling her passion for sport.

"Obviously not everyone can be a winner." Canadian heptathlete Natasha Jackson trains in Calgary but says she plans to retire after missing her chance to compete at the 2016 Olympics in Rio. (Zoe Todd/CBC) "It's very easy to get caught up and cycle away from that love of the sport and the reason you did it," she said.

Drouin's competitor, Natasha Jackson, is also turning off the Olympic road for good. Pounding over the white-chalk finish line in the final 800 meter run of her competitive career was a relief, she said.

"I'm not going to lie, I was pretty excited that I didn't have to feel that stress again," Jackson said about quitting elite sport. "It feels good to be done."

Jackson said she's ready to move to the United States with her husband, where she plans to grow her personal training business.

My performance and what I do on the track does not define me as a person. - Natasha Jackson

Before packing up her track shoes, the 27-year-old gave a nod to junior athletes warming up for their competitions.

"You can be brought so low by something not going your way, but it's not worth it," she said. "My performance and what I do on the track does not define me as a person."

Canada's official 2016 Olympic track and field team will be announced at 11 a.m. on Monday, July 11.

@ZoeHTodd