Trunk muscle forces during desk work

Abstract

Myoelectric activities of several trunk muscles were measured when subjects performed several common table-work tasks. At the same time, the contraction forces of these muscles were calculated using a biomechanical model. The measured myoelectric activities were transformed from microvolt to force data by means of regression analysis using a set of calibration experiments over the force range of interest. We suggest that that technique is more meaningful than relating the myoelectric data to, for example, a maximum voluntary contraction.

Loading of the spine was generally low in office table work. Further, the load levels were only marginally influenced by such factors as table-chair adjustment, manuscript location, and work tasks. We believe that the type of table work studied here does not influence the spine by imposing high loads, but rather by its static nature.

Keywords:

• Table work
• Back load
• Electromyography
• Mathematical model
• Spine biomechanics