Which muscle group acts as the prime mover for lower back extension?

The prime mover for lower back extension is the erector spinae muscle group. This group consists of three major muscles—iliocostalis, longissimus, and spinalis—which run parallel to the spine and play a crucial role in extending the vertebral column. When these muscles contract, they work to arch the back and maintain an upright posture, counteracting the forces that pull the spine forward.

In the context of lower back extension, the erector spinae are essential for actions such as standing up from a bent position, lifting objects from the ground, and maintaining stability during various movements. Their anatomical position and function make them the primary muscles engaged in the extension of the lumbar region of the spine.

Other muscle groups play supportive or secondary roles in back extension or are involved in different movements altogether. For example, the gluteus maximus contributes to hip extension and overall posterior chain strength but is not the main driver for lumbar extension. Similarly, the rectus abdominis primarily engages in flexing the spine rather than extending it. The quadratus lumborum provides lateral stability and helps in lateral flexion rather than being a prime mover of back extension. Thus, the erector spinae are unequivocally