Assessment of Low Back Muscle by Surface EMG

Abstract

Surface electromyography (EMG) is wide used to analyze back muscle activity. This tool is a non-invasive technique that allows the evaluation of muscle activity. Extensive researches were made to understand the surface EMG techniques and its application to the analysis of low back muscles for classifying healthy subjects and low back pain (LBP) patients, trained and non-trained subjects, subjects under rehabilitation treatments, as well as to access the muscle activity during labor tasks, sports practice or daily life activities. So, the development of biomechanical tests that enable identifying standards of muscular activity characteristic of a fatigue process, one of the causes for spine muscular-skeletal lesions, which emerges through the task repetitiveness and overload, may be a possibility of preventing lumbar lesions. The aim of this chapter is to provide a global understand of EMG parameters used to access low back muscle. For this it will be presented some issues that affect the surface EMG for low back muscle as: the reliability of low back muscle EMG; the behavior of low back muscle EMG during isometric contractions by means the analysis of the root mean square (RMS), median frequency (MF) and mean power frequency (MPF); the biomechanical parameter to identify the fatigue threshold known as Electromyographic Fatigue Threshold (EMGFT); the used of surface EMG to the assessing low back pain; and the influence of the manual load lifting to the EMG signal in low back muscle.