Final answer:
The multifidi and obliques muscles should be emphasized for postural stability.
Step-by-step explanation:
For postural stability, the two muscles that should be emphasized are the multifidi and the obliques. The multifidi muscle of the lumbar region helps extend and laterally flex the vertebral column, while the obliques play a key role in stabilizing the abdominal wall and maintaining posture. These muscles work together to provide stability and support for the body in maintaining an upright posture.