Will this help me get a flatter stomach?

i heard that situps dont really work. but i have this 5 pound weight, if i hold it to my chest, and do the situp/crunch like that, will i strengthen my abs better? thats my aim. not to lose weight, but to get really strong rock-hard abs, without weightlifting, because thats for men, and i dont want bulky muscles. do you think this would work?