Breathing pattern disorders, motor control, and low back pain

Motor control is a key component in injury prevention. Loss of motor control involves failure to control joints, commonly because of incoordination of the agonist-antagonist muscle co-activation. Three subsystems work together to maintain spinal stability: The central nervous subsystem (control), the osteoligamentous subsystem (passive), and the muscle subsystem (active). There is evidence that the effects of breathing pattern disorders, such as hyperventilation, result in a variety of negative psychological, biochemical, neurological and biomechanical influences and interferences, capable of modifying each of these three subsystems. Breathing pattern disorders (the extreme form of which is hyperventilation), automatically increase levels of anxiety and apprehension, which may be sufficient to alter motor control and to markedly influence balance control. Hyperventilation results in respiratory alkalosis, leading to reduced oxygenation of tissues (including the brain), smooth muscle constriction, heightened pain perception, speeding up of spinal reflexes, increased excitability of the corticospinal system, hyperirritability of motor and sensory axons, changes in serum calcium and magnesium levels, and encouragement of the development of myofascial trigger points – all or any of which, in one way or another, are capable of modifying normal motor control of skeletal musculature. Diaphragmatic and transversus abdominis tone are key features in provision of core stability, however it has been noted that reduction in the support offered to the spine, by the muscles of the torso, may occur if there is both a load challenge to the low back, combined with a breathing challenge. It has been demonstrated that, after approximately 60 seconds of hypercapneoa, the postural (tonic) and phasic functions of both the diaphragm and transversus abdominis are reduced or absent. Smooth muscle cells, now known to be widely embedded in connective tissues (including spinal discs, and lumbar fascia) constrict during periods of respiratory alkalosis, with as yet undetermined effects on joint stability and fascial tone. Breathing rehabilitation offers the potential for reducing the negative influences resulting from breathing pattern disorders.