Abstract
We evaluated the activity of the elector muscle of the spine with bipolar lead using electromyography during lifting of heavy loads in 11 healthy males. The weights of the load were 5%, 15%, and 30% of the body weight of each subject. The load was lifted from the floor to a table of half height of the subject. In both Preparation-Period and Carrying-Period, the %MVC was large when the weight of the load was unknown. As a result, when the weight of the load was unknown, the muscles appeared to react excessively, inducing fatigue, probably because of overestimation of the weight by the subjects. These results suggested the usefulness of the indication of the weight in handling work of heavy loads.
