In the photo from TIFF, Sydney stands in the ring: wearing shorts, a boxing tank top, with a mouthguard and gloves. Her face looks like she just knocked out her opponent. And that's no accident. The actress is playing a character who changed women's boxing in the US.
What the film's about
"Christy" tells the story of ring legend Christy Martin — world champion and the first female boxer inducted into the Nevada Boxing Hall of Fame.From the late '80s, she fought 59 bouts, became the first female boxer to appear on the cover of "Sports Illustrated" magazine, and even stepped into the ring on the same card as Mike Tyson. But her journey wasn't just athletic — her marriage to trainer Jim Martin ended with an attempt on her life.

Source:
tiff.net
Who's starring
Playing Christy is Sydney Sweeney , known from "Euphoria" and "The White Lotus." Jim Martin is played by Ben Foster, with Merritt Wever as Christy's girlfriend.The film also features Katy O'Brian, Jess Gabor, Ethan Embry, and Chad L. Coleman. The director is David Michôd, known for "The Rover" and "Animal Kingdom."
How Sydney Sweeney prepared for this role
We at zoomboola.com reported that during filming, Sweeney gained 30 pounds and went through training that included strength workouts, sparring in the ring, kickboxing, and a strict diet.
Source:
imdb.com