EVALUATION OF A SITTING AID - THE BACKUP

The effects of a portable back support, the Back-Up, were tested in 28 variables. Both subjective and objective physical load measures were recorded during sitting with and without Back-Up, most of them during VDU work. The main result was that the posture of the upper back and n eck/head was improved by the Back-Up. However, the knee straps induced unacceptable high pressure and increased significantly the discomfort in the legs. Based on these results the Back-Up was modified: the con tact area between the strap and the knee was enlarged. This modified B ack-Up was tested again for 13 variables with 10 new subjects. The kne e pressure turned out to be acceptable and the discomfort was equal to sitting without the Back-Up. Based on this research the Back-Up is co nsidered as a possible addition to more fundamental ergonomic improvem ents such as adjustable furniture and variation between sitting, stand ing and walking tasks, especially for improvement of the neck load. Ho wever, the Back-Up should not replace proper ergonomic workstation and work organization design or a backrest on the chair. Furthermore, the Back-Up should not be made obligatory, and it should be worn only for a part of the day, because it limits variation in postures.