Abstract
It is important to use a device that can objectively evaluate muscle fatigue in subjects during strength training. The purpose of this study was to determine whether the values of torque, electromyogram (EMG), and mechanomyogram (MMG) during isokinetic knee extension show statistically similar fluctuation to each other. Thirty healthy men and women (age 23.7 ± 2.1 years, height 164.9 ± 7.0 cm, weight 56.4 ± 8.0 kg) performed 50 repetitions of isokinetic knee extension (60 deg/s) at maximum voluntary contraction. EMG and MMG were recorded from the vastus lateralis (VL) and vastus medialis (VM), and the root mean square (RMS) and medium power frequency (MDF) were calculated. Torque, VL･VM EMG RMS, VL･VM MMG RMS and VL･VM EMG MDF variability were analyzed using parallel line analysis. The results indicated that only the VL MMG RMS proved to be parallel to the torque (p≥0.05). Clinically, the degree of muscle fatigue may be quantitatively and easily assessed by using VL MMG RMS during strength training, such as knee extension resistance exercise.
