Image copyright NHL via Getty Images Image caption New surgery could possibly allow Ryan Straschnitzki to stand on his own

A former Humboldt Broncos ice hockey player's life changed forever when his team bus collided with a lorry, leaving him paralysed from the chest down. The BBC spoke to the young athlete shortly after he underwent spinal surgery.

In a video posted by Ryan Straschnitzki's father Tom on social media, the 20-year-old is seen slowly moving his legs with the help of a therapist just days after undergoing epidural stimulator surgery.

At the end of the clip, the young athlete's expression switches from intense concentration and a grin washes over his face. He says when he watches the video he notices how happy he is in that moment.

"It was a crazy feeling," he told the BBC OS programme.

"I obviously didn't feel [the movement] but...I was able to control it on my own."

Mr Straschnitzki and his family have allowed Canadians into their lives since the horrific crash on 6 April 2018 on a rural road in the province of Saskatchewan.

Ten of his teammates, aged between 16 and 21, were killed along with six others, including members of the junior hockey team's staff and the bus driver. Another 13 were injured, most like Mr Straschnitzki seriously.

The tragedy shook the small community of Humboldt, where the team was based.

But people from across Canada and over 80 countries rallied around the victims and their families, raising over C$15m ($11m;£8.8m) in funds.

The Straschnitzkis have been open with the media about the tragedy, letting them document their son's challenges, and later his triumphs as he returned to the ice as a sledge hockey player, an adaptation of the sport designed for players who have a physical disability.

The latest milestone - his surgery in a clinic in Bangkok, Thailand in early November. The procedure is still relatively new and not available in Canada.

The treatment is no miracle cure, but it is considered a breakthrough procedure that, combined with intense physical therapy, could improve the health and quality of the life of those with spinal cord injuries.

It can potentially allow those with paralysis to recover some function, giving them the ability to stand on their own and have some independent movement. It can also increased muscle mass and strength in affected parts of the body.

Image copyright Getty Images Image caption Canada plays during the Paralympic Games - it's a dream of Ryan Straschnitzki's to play in Olympics

The procedure involves implanting a device in the spinal cord that sends electrical currents that connect nerve signals from the brain to spinal cord tissue.

Researched published in the New England Journal of Medicine last year documented two patients who regained a limited ability to walk with the use of a walker, though not all the patients in the study achieved that result.

Mr Straschnitzki says he now has the ability to control his core, has better sitting balance and limited leg movement. A video posted online by his father on 11 November showed him moving his right leg at the knee without help.

"Essentially it's supposed to rewire the nervous system - stuff like that - from the brain to the muscles below your injury," says Mr Straschnitzki.

Post-surgery, he has five weeks of intensive physical therapy and a "mapping" process used to enable patients to control their muscles.

"Ever since the surgery I've been able to move my legs in certain positions with certain programmes put into the device inside my back, so I'm continuing to work on those muscles and get them stronger to eventually hopefully take assisted walking to the next level and hope stand on my own and do things I wasn't able to do before," he says.

Doctors told him after the crash that he had no chance of ever walking or getting "anything back".

He says that being in wheelchair you "start to see how not accessible some places are", especially when he travels.

But through travel he has met people that "made me realise there's people out there who have it a lot worse than I do who aren't able to do what I do", he says.

"I'm very grateful for the way I am today and I kind of use that to motivate myself, thinking it could be a lot worse than it is. I take those thoughts and obviously my teammates who aren't able to do things anymore because they're not here… there's a lot of thoughts that go through my mind but I set goals for myself and surround myself with good support groups."

Earlier this year he signed a sponsorship deal with Adidas that has him starring in advertisements for the sportswear giant in Canada. He was also nominated alongside 16 other athletes for Canada's Sports Hall of Fame People's Choice Award.

And he recently made province of Alberta's para-ice hockey team and has his eyes set on Team Canada and the winter Paralympics.

"I know it's a lofty goal and it could be down the road at some point." he says. "If I don't make it at least I can say that I tried my best and that's all I can do."