The acquisition and validation of the surface electromyogram signal for evaluating muscle fatigue

The advent of new USAF aircraft control concepts necessitates the investigation of muscle fatigue in complex dynamic environments. The Acceleration Effects Branch of the Aerospace Medical Research Laboratory at Wright-Patterson Air Force Base had undertaken such a study for evaluation of fatigue in lateral G environments. Investigation of the literature indicates that the Fast Fourier Transform (FFT) of the electromyogram (EMG) signal samples could be used to determine fatigue by analysis of the center frequencies and amplitudes of the sampled power spectra. Reproducibility of data, especially in a dynamic environment, proved to be a challenge. However, acquisition and processing of the EMG signal have been optimized to give consistently reproducible and useable data. The method of sampling data and its processing are discussed.