A common reason for calling a chiropractor: “I threw my back out!” Most often, there was nothing as dramatic as throwing involved, and the patient noticed problems after they bent over to pick something off the floor. Did that sock increase its own personal gravity and become the heaviest sock in the universe? Or is there a more reasonable explanation?
Let’s look at the muscle control of the low back, since that is the region of the spine that most often is “thrown out.” The outer layers include erector spinae, quadratus lumborum, and psoas muscles that are like long fingers connecting the lumbar spine to the pelvis, thoracic spine, and rib cage. The inner layers are multifidus, interspinalis, intertransversarii, and rotatores that are shorter fingers that go between 2-4 adjacent spinal levels. So when you bend over, there are literally dozens of spinal muscles that need to work as a well-coordinated team.
Remember that muscles get their signals to contract and relax from the nervous system. Most of this coordination happens on a subconscious level, using different pathways than for “gym muscles.” For example, you can flex your bicep and your deltoid, but you can’t isolate and flex the muscle that goes between the bottom two bones in your low back. Go ahead and try it.
Your nervous system controls and coordinates all of these low back muscles. If there is a malfunction in the neurospinal system, muscles cannot coordinate themselves properly. Information from the low back to the brain is distorted and scrambled. Following the principle of “garbage in, garbage out,” signals from the brain to the low back can be ineffective. There may be too much contraction, too little, too early, too late – it’s impossible to predict exactly what will happen, but it’s a predictable fact of physiology that something subpar will occur. Like a patient throwing their back out.
The most updated research shows that chiropractic adjustments improve muscle coordination and sensorimotor integration. In 2008, the laboratory of Dr. Heidi Haavik reported using transcranial magnetic stimulation to stimulate a region of the brain to cause hand muscles to contract. After a chiropractic adjustment, muscle reaction times changed significantly.