THE RELATIONSHIPS AMONG ELECTROMYOGRAPHY, MECHANOMYOGRAPHY, AND PEAK TORQUE DURING REPEATED MAXIMAL CONCENTRIC ISOKINETIC MUSCLE ACTIONS

Abstract

365 The purpose of this study was to describe and compare the relationships among electromyography (EMG), mechanomyography (MMG), and peak torque (PT) during repeated maximal concentric isokinetic muscle actions. Nine adult males(age 22-26 years) volunteered to perform 50 maximal isokinetic concentric muscle actions of the leg extensors on a Cybex II. Bipolar surface EMG electrodes were placed over the vastus lateralis muscle with the piezoelectric MMG recording device placed between the EMG electrodes. Coefficient of determination (r2) was used to assess variance shared for EMG and MMG versus PT. One-way ANVOVA was used to examine the differences in percent (%) decline values between EMG, MMG and PT observed during the 50 repetitions. The r2 values for the EMG and MMG amplitudes versus PT values were 0.03 and 0.79, respectively. In addition, one-way ANOVA with Tukey Post Hoc tests indicated significant (p<0.05) differences in% decline values for EMG(-1.9±30.43%) and PT (65.5±6.03%), however% decline values for PT were not significantly (p>0.05) different from MMG (65.3±22.0). The results of this study demonstrated that MMG more accurately reflects torque output during fatiguing isokinetic contractions when compared to EMG.