The "girls who kicks ass" trope has been going on for some years now, at least as far back as the Alias TV show. At least in Alias, Jennifer Garner was fairly athletic. I could suspend disbelief that, with the right martial arts training, she could take down a larger opponent.
Lately, this has just gotten ridiculous. When, for example, Zoe Saldana beats up muscle-bound men much larger than herself, I just have to roll my eyes. Probably the most ridiculous example was the pilot episode of the Hawaii Five-0 reboot. Grace Park, who maybe weighs 80 pounds soaking wet and has arms you could use as toothpicks, decks a huge bodybuilder guy about four times her size, and knocks him out cold. I think she had to stand on an apple crate just to reach his face.
Even if she'd put her entire weight into the punch and charged at him from a run, he probably wouldn't even feel it, much less flinch.