Truncal stress measurement during manual handling

Abstract

The development of techniques for monitoring the trunk during exertion, such as intra-discal pressure, has made significant contributions to efforts aimed at preventing back pain at work. A new method of truncal stress measurement using strain gauges incorporated in a belt, and which is non-invasive, easily performed and relatively inexpensive, is described. The equipment response is shown to be reliable. Following a simple protocol, test of dynamic lifting from floor to knuckle height were performed by 14 male volunteers in order to determine the accuracy and repeatability of measures, and to explore associations between the load, subject and the truncal response. Testing was carried out at the place of work, and no subjects reported any difficulties with the apparatus.

The measures were reasonably reliable within sessions, errors decreasing relatively with increasing load. Between-session repeatability was generally good, exceptions pointing to improvements in the protocol. Analysis of variance and elementary regression analyses established that the individual's measured trunk stress was significantly associated (P<0·01) with the load lifted in nearly all the tests. Possible developments of the method are suggested.

Keywords:

• Back
• Abdomen
• Exertion
• Monitoring
• Physiological
• Equipment design
• Evaluation studies