The use of non-amplitude components of the myoelectric signal in identifying differences in function between the low back injured and controls.

This article primarily reviews the assessment of the non-amplitude dependent components of the myoelectric signal in assessing lumbar function in the low back injured and how persons with low back injuries may differ from the non-injured. Assessment of anomalies in function can loosely be categorized into 4 separate protocols: 1. Assessing the pattern of myoelectric activation, 2. Assessing the EMG frequency spectrum during fatigue, 3. Assessing EMG onset timing during movement and stability challenges and 4. Assessing myoelectric function with link-segment models and EMG assisted spinal models. Assessing the EMG spectrum during fatigue can discriminate between populations; however, questions regarding across day repeatability limit its ability to identify change over time. The remaining techniques are relatively new, show statistically significant differences between the low back injured and normals and provide insight into aberrant spinal stability, motor control function and spinal loading. Their response to rehabilitation programs is largely unknown suggesting a need and avenue for future research.