Maaaaan this is a tricky one. One the one hand, she was being aggressive toward the cop and needed to be detained. On the other hand, did he use excessive force to do so? I mean, there's always the chance the person has a weapon, and a tiny woman can stab you as easily as a burly man--in the case of a weapon, the safest thing to do is end the threat quickly and efficiently, in which case he is justified. But given her attire (skin tight clothing with no place to hide a weapon, both hands visibly not holding a weapon) and size, I would say there is an argument to be made for excessive force here.
All that being said, I'm not a lawyer and she was kind of acting like she needed to be popped one good time.