Crunchies or sit ups are the most commonly used and probably the best that I know of. If you're looking to define your abs more, make sure to do them the regular way and alternate going left to right as well. This will add more definition in the long run.
There are many ab exercises and you can do the P90x that has a great workout or work out videos form YouTube. It has many different routines that can keep you excited and still get a good workout.
There are several good quality ab machines available. Examples would include the Swiss ball, ab lounger, ab wheel, exercise chair, and abdominal bench.
There are many places that someone can order ab exercise equipment. Online from an exercise equipment store, a sears catalog, or even an infomercial advertising ab exercise equipment.
ab crunches work out your ab muscles.
There are several ab exercise tools on the market today. We do not know which one you are referring to.
No ab machines are not good because they don't accomplish what they are bought for. To get abs you don't need to train them, but you actually need to decrease the percentage of your body fat through any exercise. Therefore, ab machines are extremely useless.
The abdominal wheel has gotten good reviews. Here is an example: http://ezinearticles.com/?Is-the-Abdominal-Wheel-the-Most-Important-Piece-of-Exercise-Equipment-Ever?&id=1917654 There are also many stomach/ab exercises that require no equipment at all that you can do at home.
no actually any exercise is good during your period.
The Ab Doer Exercise is different from conventional ab exercises because it supports parts of your body normal exercises don't do, and it is designed to work out muscles that don't normally get worked out if you do normal ab exercises.
it is recommended to do an ab doer exercise 3 times a week for best results. It can have some consequences if you do it everyday. once you start doing exercise do ab doer just 15 times.
Many people think that sit-ups are the best ab exercises, but that is not always the case. For women, the Pilates beginner 100 exercise is very helpful for ab strengthening.
Ab exersizes focuse on your core muscels. It is a good work out for becoming more conditioned in your core area. A basic crunch would be a good starting point for ab workouts.
Crunches