TORONTO – When Mila Aung-Thwin attends film festivals around the world, the Canadian filmmaker said he sets a goal for himself: Try to briefly sneak away from the hustle of the industry event and find a trail to run on.
He acknowledged it can difficult to find the time, but worth it.
“You can do like one running excursion, and they’re so simple,” said Aung-Thwin, who co-founded the Montreal-based documentary production company EyeSteelFilm.
Aung-Thwin was fascinated with why some people push their bodies to run long distances. For nearly a decade, he thought about making a documentary about running – but without a captivating character, the idea sat dormant.
“I just find a lot of runners boring, to be honest,” said Aung-Thwin, who has worked on more than 40 documentaries including the Emmy Award-winning “Last Train Home” and the Independent Spirit Award-nominated “Up the Yangtze.”
Then Aung-Thwin met Romanian ultra-marathoner Tiberiu Useriu.
“He was very quiet, but he wasn’t boring,” the filmmaker said.
Useriu, also known as Romania’s Ice Man, a moniker he earned as a multi-time winner of a punishingly brutal ultra-marathon, the 6633 Arctic Ultra, is the subject of the Mung-Thwin-directed documentary “The Ultra Runner,” which is screening at the Toronto International Film Festival.
The film follows Useriu as he deals with physical exhaustion, sleep deprivation and frigid elements while competing in the multi-day, 612-kilometre foot race through the Canadian Arctic, where temperatures can fall to -50 C.
The on-the-ice action is spliced with re-enactments of the 52-year-old’s backstory, including his depiction of a turbulent childhood growing up in Communist Romania, followed by a period of criminal activity that eventually landed him in a high-security prison in Germany for armed robbery.
Aung-Thwin said he wanted to do Useriu’s story justice without leaning into the sensational elements of his past. The project grew from merely chronicling his extreme running pursuits to exploring how one man works through trauma to build a better future for himself and his family.
“I’ve never run more than a half-marathon and I know that you’re just telling yourself all the time you know you can just stop any time,” Aung-Thwin said. “Talking to Tibi and also studying ultra-runners, they specialize in fighting back against that self-talk.
“Tibi is like, ‘I run through my past, I run from my demons, I start to hallucinate,’ and I was like, ‘Oh, this film is about how you train your mind. It’s like, how do you go within yourself?’ And I love that idea. I love trying to explore something in cinema, which is like the internal landscape.”
Perhaps surprisingly, Useriu said he doesn’t particularly love running great distances. The first 10 kilometres is enjoyable, he said through his translator Iulia Muresan, “but anything above that is like painful and excruciating.”
“But nonetheless, running is what really saved (me) and has helped (me) tremendously in a therapeutic way,” he said.
It was in prison while serving his 23-year sentence that Useriu started running in the limited space available to him inside the guarded yard. That experience inspired the title for his autobiographic book, which translates to “27 Steps” in English, a reference to the finite number of steps at his disposal.
Useriu said he believes his traumatic past contributes to his ability to tolerate the physical and mental pain of racing hundreds of kilometres across difficult landscapes. And he said Transylvania gets quite cold in the winter, so he’s able to train in tough conditions.
Yet after completing — and winning — several ultra-marathons, Useriu said he doesn’t see himself as an elite athlete and he doesn’t view running as his purpose. Instead, he uses the exercise as a form of self-discovery.
“Because running distances like this makes you understand what you’re truly capable of, even when your body seems to not be able to do that, but your mind proves otherwise through running,” he said.
Following a rekindling of his relationship with his older brother, Alin Useriu, who is featured in the documentary, Tibi was released from prison after about a decade behind bars. Today, both brothers help run a group in Romania called Tasuleasa Social Association, which says it encourages young people to participate in civic engagement, volunteerism and environmental protection.
In Toronto this week alongside his older brother, Useriu joked he “never thought Canada could be warm.”
The film was made over a five-year period and combined pre-existing footage of Useriu running the 6633 Arctic Ultra in 2017, which he won with a time of 158 hours and 25 minutes. During a private screening of a rough cut, Useriu said watching himself traverse the Arctic was like “watching himself sort of in the third person.”
“Being an observer of your own experience, which is very different from what you are experiencing and feeling during the race,” he said. “And obviously, it’s way more fun to watch yourself do it than actually do it.”
Aung-Thwin said he hopes the takeaway from the film is “you can’t really pigeonhole people.”
“When you think of people like an ex-con or … you think of an ultra-marathon runner, you think of clichés. And I just love stories that just aren’t like that. They take you unexpected places.”
This report by The Canadian Press was first published Sept. 12, 2026.
