Many people work the area around the abdomen by doing crunches or situps expecting to get a flatter stomach, but the opposite is often the case. Working the abdominal muscles with crunches builds the muscle, but crunches alone won't reduce fat in the abdomen -- spot reducing isn't possible. Your diet, hydration level and muscle-building are factors regarding why your stomach is bigger even after crunches.
When you lift weights or do any sort of resistance training, the muscles get strained and micro-tears occur in the muscle fibers. In the process of repairing the muscles, more fibers are added to prevent further injury. This amounts to hypertrophy, or enlargement, of the muscles. The stomach muscles also get shortened, which can lead to slouching. This could also contribute to the sensation that your stomach is bigger, as slouching pushes the belly out, creating a bulging appearance.
Spot reduction is the process of focusing exercises on a specific area of the body to reduce fat. The concept of spot reduction is now considered obsolete. According to the American Council on Exercise, situps will burn calories, which will contribute to fat loss only if you are burning more calories than you are consuming.
Stretching and Posture
One way to avoid the bulging that can be associated with crunches or situps is to stretch the muscles of the abdomen before and after performing the exercises. This will help keep the muscles loose and lengthened. Standing with your shoulders down and away from your neck, with your back straight and your head up can help keep the muscles lengthened and maintain good posture -- which will keep your belly from bulging and the muscles of the abdomen stretched.
Many times exercise can lead to overeating because it builds up such an appetite. Sometimes, this can also lead to drinking too much fluids. It's possible to gain weight when you exercise because of overeating. Monitoring your portion control after your workout can help avoid a larger stomach, and keep the weight off.
The only way to a flat stomach is by burning fat and reducing your overall weight. Crunches will build the muscle and offer definition once the fat is gone. Building and strengthening the muscles of the abdomen will also give your back support, offer balance and stability and make most physical tasks easier, according to Harvard Health Publications. If there is pain associated with the bulging of the abdominal muscles, an injury or hernia could be the cause. Call a doctor if this is the case.