The Diaphragm Is More Than a Breathing Muscle

Its Well-Known Role

The diaphragm is most widely recognised as the primary muscle of quiet breathing — a dome-shaped sheet of muscle separating the thoracic and abdominal cavities that contracts and flattens to draw air into the lungs. This is true, but it is only part of the story.

A Second, Less Obvious Job: Spinal Stability

The diaphragm also plays a critical role in spinal postural control, working together with the deep abdominal and pelvic floor muscles to regulate intra-abdominal pressure and provide a stable base from which the limbs can move. Research using fine-wire EMG found the diaphragm contracts in anticipation of limb movement, independent of its respiratory rhythm, specifically to support the spine before a postural challenge arrives (Hodges & Gandevia, 2000).

Why This Dual Role Matters Clinically

Because breathing and postural control share the same muscle, a diaphragm that is working hard purely to breathe — due to poor breathing mechanics, anxiety-driven over-breathing, or chronic upper-chest breathing patterns — has less capacity left over to perform its stabilising role, and vice versa. This is one reason breathing pattern assessment can be a genuinely relevant part of addressing recurrent low back or thoracic pain, not an unrelated tangent (Bordoni & Zanier, 2013).