This paper presents methods and the first results of experiments designed to test the hypothesis that individuals in many situations generate muscle loads in excess of those necessary to maintain postural stability. Excess muscle loads of this kind are demonstrated in experiments where specific movements are performed under various constraints and where VDU-based psychophysical tests are performed with a high level of arousal. Most recordings from the psychophysical tests showed a near identical tension pattern for all muscles tested, with very low variability apart from sudden or slow changes in mean load. There were considerable inter-individual differences in tension patterns, and some implications of these findings in terms of health effects in real-life work situations are discussed.