The purpose of this investigation was to examine the effects of velocity of contraction on the electromyographic (EMG) and acoustic (AMG) responses to eccentric isokinetic exercise. Eight adult males (age=20-25 yrs) performed maximal eccentric contraction of the leg extensors at velocities of 60, 90, 120, and 180°·s-1 on a Cybex 6000 isokinetic dynamometer. Bipolar surface EMG electrodes were placed over the vastus lateralis muscle with a piezoelectric AMG recording device placed between the EMG electrodes. One-way repeated measures ANOVAs with Tukey post-hoc procedures were used to determine differences across the velocities for peak torque, EMG, and AMG.Table Although there was no change in eccentric peak torque, there were increases across the velocity for EMG and AMG. These findings suggest a velocity related association between the electrical (EMG) and mechanical (AMG) aspects of muscle contraction which is independent of peak torque production for eccentric isokinetic exercise.