Sudden movements of the spinal column during health-care work

Sudden loading of the spine is believed to contribute to the development of low back disorders for people performing patient-handling tasks. A method was developed to detect sudden movements of the spine during work. Seven women working as nursing aides at a hospital served as subjects. Anterior/posterior acceleration of the spine was measured during work on the back at the level of the first thoracolumbar segment and recorded on a data logger as were electromyographic signals from the erector spinae muscle. Static reference contractions were performed 5 times during the workday. An alarm sounded each time the acceleration exceeded 0.7g and the subjects were instructed to describe the situation that led to the acceleration. During one workday, the acceleration level exceeded 0.7g on average 5.3 times (1-12). The subjects registered 4.2 (0-11) of the alarms and 2.5 (0-8) of these occurred during patient-handling tasks. When the acceleration was in the anterior direction (forward) the maximal EMG was 30.7% (8.7-88.1) of the maximal static EMG before the situation and 87.2% (33.0-202.2) afterwards. No evidence of muscle fatigue was found based on the reference contractions. The method developed during this study is suitable to detect sudden movements during work. Relevance to industry Sudden loading or sudden movements have not been directly measured during work. Hence. it is important to develop a method to detect sudden movements during work to be able to describe the frequency of such movements. (C) 2001 Elsevier Science B.V. All rights reserved.