What Criteria Exist for Determining How Much Load Can Be Lifted Safely?

Abstract

A literature survey on recommendations for the maximum weight of the load and work loads is presented. Three different criteria are reviewed to determine the "safe" weight and permissible work loads that a person can lift. These are biomechanical, psychophysical, and metabolic/heart rate. A comparison of recommended load limits based on each of the three criteria is presented. Maximum weight of the load and work loads based on the three criteria are also compared. The comparison shows that (1) the recommendations based on a given criterion are not in agreement, (2) the maximum permissible weights of the load based on psychophysical studies are lower than those based on biomechanical criteria, and (3) the psychophysical fatigue criteria, as compared to physiological fatigue criteria, will result in greater work loads at higher frequencies of lifting. Load-pace tradeoff and effects of lifting technique and location of load on acceptable work loads are also discussed.