They use your body weight to strengthen and tone the core-stabilizing abdominal muscles. ... They promote good posture by working your lower back and gluteal muscles. With a larger range of motion, situps target more muscles than crunches and static core exercises. This makes them an ideal addition to your fitness program.

Will 100 sit-ups a day do anything?

Do sit-ups lead to six-packs? A sit-up is actually the least effective abs exercise you can do. Doing 100 sit-ups a day will not change your body in the slightest.

Will 30 situps a day do anything?

It also might be hard to find many people whose idea of a good time is doing hundreds of sit-ups. ... Are 30 sit-ups a day enough to sculpt you into hard-bellied warrior? The answer is: yes, absolutely — so long as you throw in the same number of crunches, leg-lifts, planks and other abdominal exercises.