The Role of Electromyograms in Resolving Musculoskeletal Interactions in Able-Bodied and Disabled Human Individuals

Electromyography (EMG) is a significant indicator of muscle activity and constitutes a fundamental and important tool in the fields of biomechanics, kinesiology and exercise physiology. Clinically, it serves for diagnosis and treatment monitoring. However, the raw signal obtained from the EMG of a muscle is difficult to interpret without the application of appropriate signal processing techniques. If processed in the time domain, the envelope of the rectified EMG signal may serve, with further processing, for several applications including: indication of muscle activity (Rakos et al, 1999), or estimation of force (Genadry et al, 1988). If processed in the frequency domain, EMG may point to the development of muscle fatigue (De Luca, 1997; Mizrahi et al, 2001). The electromyographic signal may also be used as a bio-control signal in conjunction with bio-assistive motion (Langzam et al 2006a, 2007; Mizrahi et al 1994; Peasgood et al, 2000; Saxena et al 1995; Thorsen et al, 1999). This Chapter deals with the role of electromyography in facilitating the biomechanical solutions of musculo-skeletal systems characterized by neuro-muscular indeterminacies.