When doing breathing exercises, there are many muscles involved in the movement, most notably the intercostal muscles and diaphragm, the diaphragm will have contraction and diastole when breathing, which will make the chest cavity bigger or smaller, and will also affect the abdomen, which will cause changes in the abdominal cavity, and the abdominal muscles will contract when breathing hard, which will participate in the breathing exercise. Both of these conditions will feel the stomach move, and can be seen from the body surface, will be able to breathe up and down with the movement, can increase the breathing movement, can provide the body with more oxygen, is a normal physiological phenomenon, belong to the abdominal breathing. Children and men abdominal breathing will be obvious, women mainly chest breathing, but usually when you can also see the stomach movement, but the amplitude will be small.