Research in this area has been inconclusive. At the moment, more and more studies seem to find no advantage to wearing a back belt while lifting or doing repetitive tasks.
One study found that the pressure of back belts on the abdomen prevents deep breathing. Another study found that belts increase blood pressure. Muscle activity of the back and trunk increases with back belts according to some studies and decreases according to others. Still other studies found no difference in muscle activity due to back belts. Researchers are working to offer clearer answers on this issue.