Rory van Ulft lets out a grunt — or as close to one as she can muster — as she hoists roughly the equivalent of her body weight above her head.

For the past year or so Rory's been lifting weights at Ottawa's JustLift gym, perfecting her technique in the two traditional Olympic weightlifting disciplines: the snatch and the clean and jerk.

She's also just six years old.

"I started doing gymnastics, and then we noticed you could get really hurt from it. So I started doing this to help get stronger," she says, still flushed after her latest workout.

"I like a lot about it. I like how you move and stuff."

Rory is one of dozens of Canadian preteens taking up the sport, which has no official lower age limit in either the Canada or the U.S. During the 2018-19 season, Canada had at least 63 Olympic-style weightlifters between the ages of seven and 13 registered for competition. The U.S had more than 400.

Rory works out with her coach at Ottawa's JustLift weightlifting gym. She's one of a handful of children who train at the Churchill Avenue gym. (Trevor Pritchard/CBC)

"When she first started, I hated it," says Lindsay Noad, van Ulft's mother. "It was so scary watching [her] lift those heavy, heavy things that I could barely lift.

"Now I look at her and I just think, 'I am so proud of you!' She's really cool and she can do amazing things."

Is it safe?

The idea of a six-year-old taking up weightlifting might make some parents wince, but as long as the right precautions are taken it should be fine, says Dr. Sasha Carsen, a pediatric orthopedic surgeon at the Children's Hospital of Eastern Ontario and an assistant professor of surgery at the University of Ottawa.

Youth weightlifting has been on the radar since at least 1990, when the American Academy of Pediatrics issued a statement urging children to "avoid the practice of weightlifting, power lifting and bodybuilding" until data could show it was safe.

That [gym] culture has to be one where they're listening to the kids. - Dr. Sasha Carsen

Since then, sports medicine experts have increasingly concluded the sport is indeed safe for pre-pubescent children, as long as they're being properly trained.

"There actually isn't much evidence to suggest that it is inherently risky — despite the fact it does kind of feel like it sort of should be," Carsen says.

Carsen says the main concerns are that children might be injured if they lift too much weight without having the right technique — a risk for adult lifters, too — and that overtraining could lead to more "subtle" injuries that impede their development.

That's why he says parents need to find certified trainers who've fostered a gym culture with kids' best interests in mind.

"That culture has to be one where they're listening to the kids," says Carsen. "One where they appreciate that the musculoskeletal health and wellness of an eight-year old is quite a bit different than an 18-year-old."

WATCH: Trainer Greg Chin talks about how to safely introduce a preteen to weightlifting

Greg Chin of Ottawa's JustLift gym explains how to safely introduce a preteen to the world of weightlifting. 0:54

One injury is 'too many'

For Rory's parents, that person is Greg Chin.

"For myself and a lot of other coaches abroad, even one injury in a child is too many," says Chin, who opened JustLift Gym seven years ago, and has coached weightlifters at the national and international level.

"So for a child Rory's age, we never load her with what we would consider to be maximum weights."

Chin has been making sure Rory's training regime — and the regime followed by his three other youth weightlifters — is focused primarily on achieving proper technique.

On Mondays, Rory practises the snatch, in which a lifter hikes a barbell over their head in one clean motion. Tuesdays are for work on the clean and jerk, a two-stage lift from the floor to the shoulder area and then above the head.

There are also footwork drills, rope climbs, jumps and other exercises designed to give Rory a broad "foundation," Chin says — one that will keep her strong and healthy while also making her a better weightlifter.

One of the core principles of Rory's training is that she's never lifting 'maximum weights,' according to JustLift gym owner Greg Chin. (Trevor Pritchard/CBC)

Off to championships

All that training appears to be paying off: this summer, Rory headed to California for the U.S. National Youth Championships, competing in the 13-and-under girls' category.

She finished eighth out of 13 kids, despite being the youngest competitor by two years — and the smallest by nearly 10 kilograms.

"She was a superstar there. Nothing fazed her," says Noad. "Everybody was just incredibly amazed by this little kid and what she could do."

Her parents say they've spoken with both a general practitioner and a sports medicine pediatrician about their daughter's training. They're convinced of two things: that the forces Rory's limbs and joints experience when she lifts weights are less than what she'd experience in many other sports, and that her coaches are looking out for her best interests.

WATCH: Rory van Ulft, 6, works on her weightlifting technique

Rory van Ulft's mother Lindsay Noad says weightlifting has given her six-year-old daughter a big confidence boost. 0:35

There's also the fact, her mother says, that she's sharing the floor with other women weightlifters who are already serving as Rory's role models.

"They're so strong, and they are here to make themselves strong, and to show that they can do whatever anybody else can do. And they are so good to Rory," says Noad.

"It's given her so much confidence, and she's got so much poise. And I'm not afraid of it anymore. Now I just think, wow, why didn't we do this sooner?"