The role of spinal ligaments in causing spinal instability, injury and low back pain in two types of occupational activities will be investigated. It is hypothesized that mechano-receptors in the spinal ligaments, when deformed due to loading, initiate sustained reflex activity in the paraspinal muscles. As creep sets in the ligaments, over time, the receptors are desensitized and the reflexive muscular activity is lost, rendering the spine exposed to instability, injury and low back pain. This research, therefore, may provide an insight for a wide range of low back pain types, ranging from idiopathic pain due to ligament strain, to that resulting from the chain reaction of injury, disc herniation and nerve damage due to lack of musculature support. A three year experimental research program consisting of the feline model will systematically explore the relationship between the electrophysiological and mechanical properties of spinal ligaments in vivo and the activity of motor units of the paraspinal and abdominal muscles in cyclic and stationary loading conditions, when the ligaments are subjected to creep as well as their recovery pattern with rest. The results of this research will provide strong insight into the neurophysiology of low back pain in common occupational activities; provide an insight to the cause of lost muscle strength and coordination and prolongation of low back pain; and delineate occupational conditions that result in low back pain and other occupational conditions that may prevent it.