The effect of leg extension training on the mean power frequency of the mechanomyographic signal

The purpose of the present investigation was to examine the effect of conce ntric isokinetic leg extension training on the mean power frequency (MPF) o f the mechanomyographic (MMG) signal. Twenty-one men were assigned into a t raining (TRN; n = 12) or control (CTL; n = 9) group. The TRN group performe d six sets of leg extensions 3 days per week for 12 weeks at a velocity of 90 degrees/s. Ail subjects were tested every 4 weeks for peak torque (PT), while MMG was recorded from the vastus lateralis. PT increased, but there w as no significant (P > 0.05) change in the MMG MPF over the 12-week trainin g period. These results indicate that MMG MPF, measured from the vastus lat eralis, was not sensitive to training-induced increases in leg-extension st rength, possibly due to competing influences of hypertrophy on the MMG sign al and/or training-induced adaptations in muscles other than the vastus lat eralis. (C) 2000 John Wiley & Sons, Inc.