You don't need expensive exercise aids to work out your stomach muscles. Quite a few of them utilize something as simple as a wall. Using a wall in your abdominal exercises has the added benefit of keeping your spine straight while these exercises help to tone and tighten your stomach.
The stomach vacuum is an exercise that is simple to do, but it may be one of the most important exercises you do. The deepest muscle of your abs, your transverse abdominis, is strengthened by performing the stomach vacuum. The exercise may be done lying on your back or with your back against a wall. Your spine should be held straight. By pressing your back against a solid surface, you isolate the muscles of your abs. Stand against the wall with your lower back in a neutral position, which simply means that your lower back follows the natural curve of your spine. There is about a hand-width distance between your back and the wall when it is in neutral. The exact distance varies per person. Then, take a deep breath to relax your abs. Breathe out fully and pull in your abs as if trying to make your stomach touch your spine. Exhaling helps you activate your abs. Hold this position for as long as you can.
The pelvic tilt is another exercise for the stomach that may be done against a wall or lying on the floor. Unlike the stomach vacuum, this exercise works the rectus abdominis. The rectus abdominis is the "six-pack" muscle. To do the pelvic tilt against a wall, stand with your back against a wall and your legs straight. Press your arms and palms flat against wall. Allow your lower back to arch away from the wall, but keep your head, shoulders and buttocks touching the wall. Then, tuck your pelvis and squeeze your abs to press your back flat against the wall. This is one repetition.
The side bends exercise strengthens the lateral abs, also called the obliques. To isolate the obliques, you must stand up straight and then bend sideways without rotating your spine. Placing your back against a wall ensures that you use correct technique to bend sideways without twisting. Begin standing against a wall with your arms hanging at your sides. The feet are placed about shoulder's width distance apart. Raise your left arm over your head and lean to the right, keeping your shoulders and back in contact with the wall. The right hand slides down the wall with the arm straight. Stand back up straight and switch the position of your arms to lean to the left and work the opposite side.