Japan's national sport of sumo conjures up visions of very large loincloth-clad men crashing into one another. But lately, a new breed of sumo wrestler is stepping into the ring.

At just over 50 pounds, Mei Kigawa may not look like a sumo wrestler, but the shy fifth-grader is no pushover.

"She's had plenty of bruises," her mom said. "But so far no broken bones."

Kigawa was one of the young girls who competed in a national tournament in Osaka, CBS News correspondent Lucy Kraft reports. The girls trained for a whole year for matches that are over in seconds – sometimes one second.

Aside from modified attire and separate weight classes, the rules for female sumo wrestlers are identical to professional sumo. And despite sumo's reputation as a contact sport for brawling behemoths, coaches say it's the ideal workout for just about anyone.

"Sumo is good exercise, but it's also the most painful thing you can do," said Irish native John Gunning, a Tokyo-based sports writer and former amateur sumo wrestler.

The reigning lightweight queen is 26-year-old Miku Yamanaka, who has perfected her initial charge.

"I focus on crouching as low as possible, charging in fast, as hard as I can. After that, I just leave it up to my training and don't think about anything," Yamanaka said.

Women's sumo gained visibility with a 2018 Netflix film "Little Miss Sumo," documenting the struggles of females to gain respect in an ancient sport. Yet despite their rising profiles and achievements, females are still barred from competing in sumo's mecca, the Ryōgoku Kokugikan arena in Tokyo, which President Trump visited this year.

"Kokugikan has a magic all its own. Even the lighting is special. All women sumo wrestlers take pride in Japan's national sport and want to compete there," Yamanaka said.

While many support opening arenas to female wrestlers, a pro women's division seems like a pipe dream.

Without the big arenas, TV exposure, and lavish budget of pro sumo, women's amateur sumo remains a tiny niche of the sports universe.