Objectives : To evaluate the clinical utility of Muscle Energy Techniques(MET) in Elector Spinae Muscle on subjects. Methods : We compared electrical activity between a before MET and a after MET in Elector Spinae Muscle on subjects in same group(n=26) in dynamic flexion-reextension state during five seconds. We analyzed amplitudes and areas of electrical activity and Asymmetry Index(AI) and Median Edge Frequency(MEF). Results : 1. After MET in Elector Spinae Muscle on subjects were lower electrical activity than before MET in Elector Spinae Muscle on subjects but it is not a pointless observation(p<0.05). 2. AI of the after MET in Elector Spinae Muscle on subjects significantly decreased compared with before MET in Elector Spinae Muscle on subjects(p<0.05). 3. MEF of the after MET in Elector Spinae Muscle on subjects decreased compared with before MET in Elector Spinae Muscle on subjects but it is not a pointless observation(p<0.05). Conclusions : According to above results, there is clinical effect MET on subjects.