During inhalation, which area of the trunk expands most for a diaphragmatic breather?

The correct choice is the abdominal region because during diaphragmatic breathing, the diaphragm contracts and moves downward, allowing the lungs to expand. This movement increases the volume of the thoracic cavity, and as a result, the pressure inside the abdominal cavity decreases. Consequently, the abdominal wall pushes outward as air fills the lungs, leading to a noticeable expansion in this area. This is a key characteristic of diaphragmatic breathing, where the focus is on utilizing the diaphragm fully, promoting more efficient lung function and oxygen exchange.

In contrast, the chest region primarily involves upper chest expansion, which is more characteristic of shallow or thoracic breathing rather than diaphragmatic breathing. The back region may experience some expansion as a secondary effect but is not the primary focus during proper diaphragmatic breathing. The shoulder region generally remains stable, as diaphragmatic breathing encourages relaxed shoulder positioning and minimizes tension in that area. Thus, the abdominal region is the most affected area during this style of breathing.