Rectus Abdominis
Erector spinae
Erector Spinae are extensor muscles encompasing the neck and trunk. Extensor movement is antagonistic to flexor movement. Therefore, find a muscle of the neck and a muscle of the trunk that act as flexors. That should answer your question without giving away all of the milk and honey!
Rectus abdominis is the prime agonist and the superior and inferior oblique muscles are synergists. Erector spinae is an antagonist including a number of other muscles of the back.
The erector spinae
erector spinae group
Erector Spinae
Some effective erector spinae exercises to strengthen your back muscles include deadlifts, back extensions, and supermans.
erector spinae for spinal extension and quadratus lumborum for spinal abduction
The erector spinae is a group of muscles that run along the spine and help maintain posture by supporting the spine and keeping the body upright. These muscles also play a role in bending and rotating the spine.
erectus spinae
The erector spinae
Erector spinae