The sacroiliac joint is where the upper body meets the lower body. It is the center of motion, the center of shock absorption, and the center of power transfer between the upper and lower body.  When we talk about core, this is what we are talking about, the sacroiliac joint, not the lumbar spine. 

Although lumbar disc herniation can lead to extremely severe pain due to pressure on a nerve, most of us don’t have extremely severe pain. The aches and pains that we learn to live with, that limit our activities and burden our lives are not usually caused by disc herniation.

Historically, the sacroiliac joint had been regarded as the main cause of back pain. But, in 1934, the lumbar disc was also found to be a potential source of pain and it gained prominence. Now, with the emergence of the science of biomechanics, the sacroiliac joint is regaining its standing as the main cause of back, pelvic, and hip pain, and may even be the underlying biomechanical cause of disc herniation.