Table 2. AEMG values in each quadriceps femoris muscle (VL= vastus lateralis, VM = vastus medialis, RF = rectus femoris) measured before and after 20min of vibration and that of relative change after vibration in both study groups. Data are means (±SD). Muscles Type of contraction Pre-Vibration (mV) Post-Vibration (mV) F value P value VL Concentric .071 (.032) .062 (.190) Pre vs. Post 7.279 .0308 Eccentric .126 (.067) .105 (.057) Con vs. Ecc 7.188 .0315 Interaction .951 .3619 VM Concentric .074 (.015) .070 (.160) Pre vs. Post 9.556 .0175 Eccentric .130 (.050) .105 (.040) Con vs. Ecc 12.403 .0097 Interaction 7.037 .0328 RF Concentric .158 (.069) .149 (.072) Pre vs. Post .411 .5416 Eccentric .194 (.102) .161 (.085) Con vs. Ecc 4.176 .0803 Interaction 4.232 .0787