MECHANOMYOGRAPHIC SENSOR - A Triaxial Accelerometry Approach

Abstract

Recently, accelerometers have been used to acquire mechanomyography signals. These signals are due to muscle lateral oscillations during contraction. In this study, a sensor acquired such vibrations in three directions. A triaxial accelerometer-based sensor was constructed and tested with a controlled mechanical vibrator and subwoofer speaker (both from 10Hz up to 40Hz) during isokinetic muscle contraction (3 volunteers, 50 extensions at 300 degrees/s). With triaxial accelerometry it was possible to compute the MMG modulus signal. For normalised and average values, MMG amplitude presented strong correlation coefficients (R=0,89) with RMS and peak torque. Below 80% of normalised data, MMG amplitude and torque values (RMS and peak) seem to converge.