Muscles response to imposed demands. They can be made "uncomfortable" and forced to grow simply by adding weight or repetitions. My advice to you is to change your routine with a purpose in mind. Training in a more traditional strength range of less than 8 repetitions going all the way down to singles, form permitting, will further force adaptation, albeit different than your 25 rep example. Name a goal- learn how to train for that specific goal (not making muscle uncomfortable)- train for that goal.