The effects of work load and operation position on the spine during manualactivity

The objective of this research is to provide designers with efficient work posture guidance for the design of workplaces. Analysis of data produced th rough the use of electromyography (EMG) facilitated the achievement of this objective. In the experimental study, essential anthropometric data such as body link length, elbow flexion angles, body weight, and load weights were collected on the basis of a static a-dimensional model. Three different load weights and carrying positions were considered, and the muscle activity of the back musculature was recorded with EMG. The relationships among normalized EMG levels, muscle forces, compression f orces, and moments were analyzed. Finally, a linear regression equation of muscle forces at normalized EMG levels, as well as a quadratic regression e quation of normalized EMG levels on load weights and carrying positions, wa s developed. (C) 1999 John Wiley & Sons, Inc.