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The effects of isometric strength training of the quadriceps femoris on electromyography, mechanomyography, and peak torque
The purpose of the present investigation was to examine the electromyographic (EMG), mechanomyographic (MMG), and peak torque (PT) responses to eight weeks of isometric strength training of the quadriceps femoris. Thirteen adult male volunteers (age 19–29) were randomly assigned to a training (TRN) group (n = 6) or a control (CTL) group (n = 7). Maximal isometric PT of the quadriceps femoris was measured along with EMG amplitude and MMG amplitude for the vastus lateralis (VL) and the vastus medialis (VM) at leg flexion angles in which the Cybex II lever arm was 30°, 60°, and 90° below the horizontal plane. Measurements were collected three times during the study (week 0, week 4, and week 8). The TRN subjects performed eight weeks of unilateral isometric muscle actions with the non-dominant limb. During the first two weeks, subjects performed two sets of isometric muscle actions at 80% of their maximal isometric peak torque at 60° of leg flexion. For the remaining six weeks, subjects performed three sets of isometric muscle actions at 80% of their maximal isometric peak torque. Maximal isometric peak torque at 60° of leg flexion was reassessed at the end of the fourth week of training to adjust the training torque values. Each set consisted of ten repetitions with each repetition lasting six seconds. The subjects trained three times a week. The results indicated a significant increase in PT for the non-dominant limb of the TRN group at the training angle of 60° of leg flexion only. There was a significant increase in EMG amplitude as a result of training for the VL between week 0 and week 8. There was no training effect on MMG amplitude. These findings indicate that an increase in neural drive to the VL might be responsible for the training induced increase in PT. ^
Smith, Douglas Boyd, "The effects of isometric strength training of the quadriceps femoris on electromyography, mechanomyography, and peak torque" (2001). ETD collection for University of Nebraska - Lincoln. AAI3009737.