Abstract
The purpose of this study was to investigate trunk muscle activity on lifting with trunk rotation (6.8 kg weight, elevation from knee to shoulder, 50cm lateral shift). Twenty healthy male volunteers participated in this study. Muscle activities of the elector spinae and the oblique muscles were measured bilaterally using a surface electromyograph. Muscle activity of the subjects -with or without lumbar belt-were compared in with each subject peforming the same task. Myoelectric activities (%MVC) of the elector spinae muscles were 4.6 times larger than those of oblique muscles. No differences were observed between right and left muscle groupes. Muscle activity was significantly reduced when subjects wore the lumbar belt; elector spinae muscles by 14.6%, oblique muscles by 18.9%. Conclusion, elector spinae muscles played a greater role in lifting tasks involving trunk rotation, and the use of a lumbar belt reduced the load of both trunk muscles.
