Skeletal Muscular Patterning: Topographical Analysis of the Integrated Electromyogram

Abstract
The extraction of mean amplitude from integrated electromyographic (IEMG) responses provides a valid but limited measure of muscle action potentials (MAPs). More comprehensive topographical analyses of IEMG responses based on frequency analyses are unsatisfactory since IEMG responses are aperiodic, and autoregressive procedures may be unsatisfactory since autocorrelations constitute an irreversible transformation of the original waveform, represent a substantial loss of information in contrast to the original waveform, and harbor little apparent relationship to MAPs. In a Theoretical Investigation, a mathematical procedure is developed to quantify topographical features of both the amplitude and temporal dimensions of the IEMG response. Procedures for extracting these parameters and the relationship between each and the recruitment of MAPs are illustrated. In a Validation Study, surface electromyograms are recorded from the preferred forearm under various conditions of mild isometric forearm contraction. Results support the viability, reproducibility, and validity of the topographical analysis.