Appl Ergon. 1989 Dec;20(4):307-12. doi: 10.1016/0003-6870(89)90196-8.
Applied ergonomics
S E Johansson, G Ljunggren
PMID: 15676751 DOI: 10.1016/0003-6870(89)90196-8
Nine cleaners were monitored for four hours while performing their ordinary work. They rated their perceived exertion on Borg's CR-10 scale every five minutes and their heart rates were recorded every minute. It was found that the subjects worked on a physiological 'steady-state' level, meaning that their heart rates were about the same regardless of the work performed. Their ratings of perceived exertion varied, however, but were all 'fairly strong' or stronger. During more than 80% of the time, the work periods on the different tasks were shorter than 15 min. On the basis of the results of a bicycle ergometer test, it was determined that the actual level of exertion during the ordinary work corresponded to about 35% of the subjects' estimated maximal oxygen uptake. Most subjects had back symptoms and more than half of them reported symptoms involving the neck, shoulders, wrists and hands. The varying intensities indicate where the problems are most critical.
