During the Hundred, how does precise lateral thoracic breathing directly facilitate the engagement of the transversus abdominis to stabilize the lumbar spine against limb movement?

During The Hundred, a Pilates exercise involving supine arm and leg movements, precise lateral thoracic breathing directly facilitates transversus abdominis engagement to stabilize the lumbar spine. Lateral thoracic breathing, also known as lateral costal breathing, is a controlled breathing technique where the focus is on expanding the rib cage outward and sideways during inhalation, rather than primarily forward into the abdomen or upward into the chest. As you inhale, the diaphragm, the primary muscle of respiration, descends, and the lower ribs expand laterally. During exhalation, the diaphragm ascends, and the ribs gently draw back inward and downward. This controlled movement of t....