Constant physical work is the leading cause of low back pain (LBP) in nurses, which affects their well-being and working efficiency. With this study, we aimed to explore the features of lumbar muscles including multifidi (MF) and musculus tiansversus abdominis (MTA) of nurses with LBP suffering from lumbar disc herniation (LDH). We estimated the degree of lumbar muscle strain by compaiiug the lumbar muscle thickness between nurses with LDH and healthy subjects. In this experiment participated thirty-one patients with LDH and 37 healthy controls. We asked the subjects to perform five cycles of forward and backward bending from a standing position. Meanwhile, we captured sonomyographic images of multifidi (MF) and musculi trausversus abdominis (MTA). As results, the muscle thickness of MTA from light side showed significant difference between healthy female subjects and female nurses with LDH (p=0.00K0.05 ). LDH subjects exhibited a lower muscle thickness than that of healthy subjects duiing forward bending. Also, the MTA thickness of controls was lower than that of LDH nurses duiing backward bending. We also found that higher age of LDH nurses was associated with higher muscle thickness of the mo explored muscles. Higher scores from the Oswestry Disability Questionnaire scores correspond to a higher thickness of light MF and left MTA and lower thickness of the light MTA, respectively.