Abstract
This paper discusses the maximum amount of weight that an individual can be expected to lift comfortably and without strain. Recommendations based on empirical estimates, biomechanical techniques, and psychophysical methods are reviewed, including those of the International Labour Office, the Swiss Accident Insurance Institute, the Danish National Association for Infantile Paralysis, and the U. S. Air Force. The approach used in two Air Force experiments is identified as a variation of the psychophysical method of magnitude production. An improved experimental design is described which includes the following advantages: (1) The control of additional variables not considered in previous studies. (2) Experimental controls and statistical procedures found necessary for use in psychophysical experiments. (3) Instructions and tasks which are more applicable to industrial situations. (4) Subjects who are experienced industrial workers, older and better conditioned to the lifting task. The results collected to date are discussed and compared with those of other investigators.
