ABSTRACT
Electromyography and dynamography are the only basic methods in biomechanical motion analysis that provide information about non-visible activities and forces. For example, lifting a leg from a horizontal position requires the generation of a force greater than opposing force of gravity before motion becomes visible. While dynamography is usually limited to the description of a resultant force, electromyography is useful because it can show the time, duration and with some restrictions the degree of activity of a particular muscle participating in motion. Electromyography acquires special significance when dynamography is not applicable, e.g. during flight phase in sprint running. Thus exact knowledge of the electromechanical delay (EMD) as the distinct time shift between the onset of electrical activity (EMG) and the onset of the mechanical response (force) can provide important conclusions for the motion analysis of the mechanical effectiveness of a particular muscle whose activity is made evident via the corresponding EMG.
