2335 PURPOSE: The present investigation examined the peak torque (PT), mechanomyographic (MMG), and electromyographic (EMG) responses of the vastus medialis (VM) to eight weeks of isometric leg extension strength training. METHODS: Thirteen adult male volunteers (age19-29) were randomly assigned to a training (TRN) group (n = 6) or a control (CTL) group (n = 7). Maximal isometric PT for leg extension was measured along with EMG and MMG amplitude at leg flexion angles of 30°, 60°, and 90°. Measurements were collected three times during the study (weeks 0, 4, and 8). The TRN subjects performed unilateral isometric muscle actions with the non-dominant (ND) limb at 60° of leg flexion. The first two weeks, subjects performed two sets of muscle actions at 80% of their maximal isometric PT at 60°. For the remaining six weeks, subjects performed three sets of muscle actions at 80% of their maximal isometric PT. Maximal PT at 60° was reassessed at the end of the fourth week of training to adjust the training torque values. Each set consisted of ten repetitions lasting six seconds each. The subjects trained three times a week. RESULTS: The results indicated significant (p<0.05) increases in PT for the ND limb of the TRN group between week 0 and week 4 and between week 0 and week 8 of 9.8% and 14.8% respectively, at 60°. There was also a significant (p<0.05) increase in EMG amplitude for the ND limb of the TRN group between week 0 and week 8 of 46% at 60°. There was no training effect on MMG amplitude. CONCLUSION: These findings indicated that changes in muscle activation of the vastus medialis might be responsible for the training-induced increase in PT. The findings also indicated that there was no cross-training effect in the untrained limb of the TRN group for PT, MMG amplitude, and EMG amplitude.