Purpose : The purpose of this study is to define the change of lumbar asymmetry multifidus muscles when upper extremity PNF pattern. Methods : For this research, twenty-nine asymptomatic participants were voluntary attended. Under the identical conditions, Multifidus muscles were measured standing position and on L4,L5 vertebral level by MyLabOne (ESAOTE, Netherland with a 3.5MHz covex array transducer). The upper extrimity PNF pattern used to activate the multifidus ipsilateral and cotralateral. Results : Results of analysis showed that at the L4, L5 vertebral level, healthy asymtomativ subjects had asymmetry multifidus muscles size. The depth of the multifidus muscles were significantly increased at contralateral upper extrimity PNF pattern, but no significant differences were comparison ipsilateral with contralateral. Conclusion : The multifidus muscle in asymptomatic subjects clinical significance asymmetry. Contralateral upper extrimity PNF pattern seems to be the most suitable exercise for strenthen the smaller size of the multifidus. This study will be used as a prevention method of LBP.