ASSESSMENT OF LUMBAR EMG DURING STATIC AND DYNAMIC ACTIVITY IN PAIN-FREE NORMALS - IMPLICATIONS FOR MUSCLE SCANNING PROTOCOLS

The purpose of this study was to provide a thorough description of lum bar surface integrated electromyography (EMG) in pain-free normals dur ing a standardized assessment protocol of static isometric and unresis ted dynamic tasks. It has been proposed that in pain-free normals, sym metrical tasks that bend the trunk forward or extend the trunk backwar d produce symmetrical paraspinal EMG activity, and asymmetrical tasks that rotate or laterally bend the trunk produce asymmetrical paraspina l EMG activity. In addition, it has been observed that lumbar EMG asse ssment during static tasks has been more consistent than tasks involvi ng dynamic activities. Twenty-eight pain-free normals were assessed du ring symmetrical and asymmetrical tasks in both static and dynamic act ivities in a counterbalanced manner. The assessment of paraspinal EMG patterns was conducted while subjects were secured in a triaxial dynam ometer, which provided standardization of body position and concurrent measurement of torque, range of motion, and velocity. The results pro vided experimental evidence for the above-stated propositions. An impl ication derived from this research is that clinicians may be better se rved utilizing local norms when using EMG for classification purposes.