ABSTRACT
Objective To study the role of transversus abdominis in lumbar spine stability,and to find a way to assess the abdominal muscles function.Methods 15 healthy subjects performed rapid arm flexion,abduction,and exten- sion.Electromyographic(EMG)activity of transversus abdominis,rectus abdominis,obliquus externus abdominis, obliquus internus abdominis and deltoid was evaluated with surface electrodes,latency between onset of the abdominal muscles and of the deltoid was calculated.Results The transversus abdominis invariably contracted before the deltoid and the other abdominal muscles,except the obliquus internus abdominis during arm extension.Conclusion(1)It's an effective way that latency between onset of abdominal muscles and of deltoid is used to assess the abdominal muscles function with arm movement as a factor of influencing the balance of spine.(2)Transversus abdominis,as deeper mus- cles acting earlier with all movements play an important role in maintaining the stability of lumbar spine.