This study explores the complex role of the diaphragm, traditionally considered essential in respiratory physiology, expanding understanding of its multifunctionality. Beyond respiratory mechanics, the diaphragm contributes to postural stabilization, lumbar support, and regulation of intra-abdominal pressure (IAP). By analyzing the diaphragm's eccentric contraction, we introduce two innovative concepts: "Diaphragm Antagonist Muscles" (DAM) and "Centration". DAM represents an evolution of the abdominal belt concept, integrating the pelvic floor and lower posterior trunk muscles. This muscular synergy is vital for respiratory dynamics and functions such as posture and integrity of the musculoskeletal, pressure, and postural systems. Centration, proposed as a conscious modulation skill of IAP, activates a neurophysiological interaction between the diaphragm, lower posterior trunk muscles, and the pelvic floor, revealing new implications of the diaphragm in sports, health, and kinesiological contexts.