Before you search on line for ab exercise machines, here is a synopsis of five ab exercisers to to flatten abs.
The Ab King Pro ab exercise machine looks like a workout bench. It has a metal handle arching over it. The purpose of the handle is to grab it to help you do crunches. The upper part of the bench supports your neck and moves along with your upper body as you pull up during the crunch.
To use, you lie on the bench and place your legs on the floor or on the foot rest. You then grab the bar handle and do crunches. Really the only exercise that you can do with this machine is the basic crunch which you can do on the floor.
Ab Circle Pro
There are two exercises which you can do with Ab Circle Pro. The first exercise, called the flexion movement, works your abs by rotating your body from side to side. If this exercise is done quickly enough, it is suppose to give you a cardio workout.
The second exercise is known as the thigh and bun movement. A special pin is adjusted to allow the machine to work for this exercise. This position also allows for the advanced flexion movement. In this exercise you rotate your body from side to side with both legs close together.
and neck while the rolling cushion action gently massages the back.
There are three resistance levels, and several crunch style exercises that you can do with it.
Basically an ab roller is a bent metal frame that is used to assist you in doing a crunch. You lay down on the floor and rest your head on the pad. This helps you to maintain a straight neck. You grab the handle and use the roll of the machine to guide you through the crunch. You can do both straight and sideways crunches.
The Ab Coaster
Searching online and following links is a good way to find more information about ab exercises and ab exercise machines.