Do crunches work?

Low bodyfat=see them abs!

Most people if they have been working their abs correctly over a number of months have fantastic set of well formed abdominal muscles. However, they will never be visible because of a layer of fat covering them as the last poster said. All the crunches in the world won't change that.

Work on reducing BF% if you want to see your abs. As it is not possible to spot reduce fat you have to work on lowering your overall BF% across your whole body. As a general rule of thumb women will start noticing their abs (the lines as you say) at about 20% with noticeable separation at about 18% and under.

The abs have a number of functions including protecting internal organs and providing core stability. However one of their principal functions is to bring the rib cage closer to the pelvis. Anything which provides that type movement will isolate the muscles and work them. This is why crunches work. However don't forget that the abs do not simply include the rectus abdominis (the ones in the middle.) They also include other muscles but particularly the oblique and transverse abdominis (the ones at the side) To work them on the basis of what was previously discussed you need to adopt a twisting motion from side to side. Unsuprisingly a twisting ab crunch works them effectively.

Next rep range. This is the subject of debate. However, my view that abdominal muscles are just that, MUSCLES. They should be worked like other muscles as a result. Doing hundreds of crunches at high speed will do very little but mimic a cardio workout and place excessive reptitive strain on your spine. Clearly not a good thing. In my opinion a lower rep range where you perform the exercise s-l-o-w-l-y through the full range of motion with good form is preferred For "big" exercise where the spine is supported such as bench press or DL a low rep range is up to about 4- 8 reps. With abs because your spine is enaged and in motion anything from 12 - 20 should be enough and considered "low."

Now, rest time. As with your muscles this is very important. My opinion is if you have worked hard enough then you should allow at least 48 hours before working your abs DIRECTLY again. So if you do crunches to work your rectus abdominis on Monday, don't do them again until Wednesday. There's nothing to stop you working alternate ab muscles on alternate days though. Eg crunches on Monday and side bends on Tuesday.

Finally, there's nothing wrong with exercising your abs INDIRECTLY every day through running or weight training exericse which involve core use. In fact that is beneficial as a strong core has numerous health benefits. In fact, it is possible to have a good set of abs without ever doing a single specific ab exercises due to this. However, your BF will need to be sufficiently low to see them as said right at the very beginning.

Even if you DO have fat covering your abs doing crunches before you lose all the weight works! No reason NOT to do the crunches even if you are fat! A strong core is necessary in so many ways. Then as the weight comes off you have some definition already.