"I don't dance too much anymore, because my body really hurts - my knees hurt, my hips hurt," she told AAP.
A new documentary following Bartho's students at the Brent St dance school in Sydney goes some way to explaining why that might be: elite dancers must be very, very tough to succeed.
In one scene, Bartho puts her shoulder out during a rehearsal, only to strap on an ice pack and keep on going, while in another, one aspiring dancer ends up in hospital after a lift that goes wrong.
The students in Dance Life are not short of drive or ambition. (HANDOUT/AMAZON PRIME VIDEO)
A former Brent St student herself, Bartho graduated just after the heyday of the television program So You Think You Can Dance, a time of huge demand for professional dancers in Australia.
She hopes the Amazon Prime series titled Dance Life will serve as a showcase for local dancers that will lead to a resurgence in the discipline.
"I want to put dance in the forefront again, I want everyone to want to work with dancers and get our industry going again," she said.
The students in Dance Life are not short of drive or ambition: one says she wants to be on every stage and billboard in Sydney.
Yet becoming a professional dancer is, on the numbers, only for the very few.
Of more than 2000 students who audition for the school's full-time program, only 90 are accepted each year, and of those, only five or 10 might have a professional career.
There are also industry expectations about how dancers should look - everyone has to fit into a box, according to former student Emily Smith, from Emu Plains in western Sydney.
Emily Smith (far left) struggled to see herself as good enough to dance with her classmates. (HANDOUT/AMAZON PRIME VIDEO)
Part of the class of 2022 featured in the series, Smith struggled to fit in and see herself as good enough to dance with her classmates.
"I've always been less confident in myself because I've never really fit a certain box in the dance industry, which has always been quite stressful," she told AAP.
Dance Life also reveals the toughness required to survive dance school isn't just physical - the students are also coping with life outside the rehearsal studio.
Smith, for example, reveals she was subject to extreme family violence growing up, and was raised by her grandparents after her mother died and her father abandoned her.
But as the series builds towards the class of 2022's make-or-break graduate performances in front of family, friends and all-important potential agents, she finds confidence and purpose, and hopes her grandparents would be proud.
"We've all been through a lot together, the three of us, and I would not be here without them," she said.
The students and teachers watched the five-hour series together in a Sydney cinema, which Bartho found nerve-wracking as she discovered what her students say about her behind her back.
Success on the stage is not about talent so much as determination and sheer hard work. (HANDOUT/AMAZON PRIME VIDEO)
"I forget sometimes how much impact you have on a kid's life ... sometimes you need to remember that you might say one thing, but it might stay with them for the rest of their life," she said.
She agrees her teaching is just as tough as it appears on screen, but with good reason - dancers need to be at the top of their game ahead of a big performance.
Ultimately, success on the stage is not about talent so much as determination and sheer hard work, according to Bartho - all showcased in Dance Life.
"Our kids are amazing, our industry is amazing, I want everyone to see it," she said.
Dance Life premieres on Prime Video Australia on Friday.
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