Also known as the transverse abdominus, this is the deepest of the four main abdominal muscles, and it is the most crucial to lower back support. This is one dedicated muscle. It does not bend the spine, nor does it twist it or cause the spine to bend sideways. Its only action and purpose is to stabilize and support the lower back.
When you contract this muscle your waist tightens, your belly button pulls in, and the pelvis and back are stabilized.
The transverse abdominus is sometimes referred to as the “natural girdle.” It is certainly the most important single muscle when it comes to spinal stability and lower back health.
