Hilary Swank portrayed Mary Margaret "Maggie" Fitzgerald, an aspiring boxer in the 2004 sports drama Million Dollar Baby. To be convincing in that role, the producers asked Hilary to gain 10 pounds of muscle mass, but she gained 19 instead.

To obtain the physique of a boxer, she trained six times a week, dedicating two and a half hours to boxing and an hour and a half to two hours to lifting weights. On top of that, she was strictly following what she ate as to gain muscle she had to maintain a high protein intake.

But the training led to the actress getting blisters and she was popping them in the bathtub, which resulted in an infection that almost reached her heart, which would have been detrimental.