Design of an electronic system for monitoring muscle activity in weight-lifting

Abstract

Electronic systems based on body area networks can be used to monitor sports performance. These systems use sensors to acquire signals from the athlete while performing the exercises, and a communication system to transmit the data to a computer or smart phone to analyze it. That information can be used to evaluate sport performance quantitatively, prevent and treat injuries, and design personalized training programs. Surface electromyography (SEMG) is used to study muscle function during dynamic activities, and can be used for the biomechanical analysis of gait, sports gesture, muscle fatigue, and sports performance. This paper describes the design, construction and evaluation of an electronic circuit for monitoring muscle activation during weight-lifting exercises. The system has the following stages: an instrumentation amplifier to amplify the electromyographic (EMG) signal and reduce common-mode noise, a band-pass filter to limit the frequency content to the range 30 to 500 Hz, a precision rectifier, and a low-pass filter with cut-off frequency of 35 Hz, to obtain the signal envelope. The system uses two 9 V batteries, and is portable. Preliminary tests have been done and the acquired EMG signal has amplitudes in the order of volts. © 2014 IEEE.