I've only seen the first episode, but it looked like the actress did most of the fight scene at the end. The fight kind of suffered for it though, with poorly placed kicks landing two feet away from a bad guys face.
I'm sure they use stunt doubles though, like any other show, but since the faces of the characters/actresses are still shown after they change (unlike Rider or Super Sentai) they're kind of forced to keep the actress in there more.
I'm just kind of rambling at this point.