Inner Unit- Transverse Abdominis(TVA), Diaphragm, multifidus, pelvic floor
Outer Unit- Rectus Abdominis( 6 pack), Internal and External Obliques(muscles along the sides of your torso), Erector Spinae(larger muscles along spine)

Transverse Abdominis(TVA)
-your natural weight belt, stabilizes the core, major stabilizer of the low back.
-the transverse abdominis(TVA), multifidus, and pelvic floor muscles are on the same neurological loop, therefore if the TVA is not working properly, these muscles will also not function properly

Multifidus
-the multifidis are the stabilizers of the spine. They are small muscles that are very deep and right up against the vertebra. Originate from the sacrum up through the axis.
-multifidus abnormalities are associated with many back conditions such as acute low back pain, herniated discs, unstable vertebrae, scoliosis, and chronic back pain.
-the greater the lower limb muscle impairment, the greater the tendency toward atrophy of the multifidus muscle in patients with lumbar disc herniation.

Enjoy some nice California waves.