Static lifting strengths at different exertion heights

Abstract

Twelve healthy right-handed male subjects were recruited to investigate their maximum static lifting strengths for right-handed, left-handed and two-handed exertions at five different exertion heights (10, 45, 75, 105, and 140 cm). The results showed that the highest lifting strength occurred in the interval of exertion height between 10 and 45 cm while the lowest lifting strength at the exertion height of 105 cm. The hand dexterity seemed to have little connection with lifting strengths especially for higher exertion heights. This study suggests that two-handed lifting should be encouraged since it resulted in both higher lifting strengths and less strains on load-bearing shoulder, elbow and wrist structures compared with one-handed lifting. Additionally, the sum of right-handed and left-handed lifting strengths was greater than the two-handed lifting strength for exertion height below 75 cm, while it was smaller than the two-handed lifting strength at 140 cm exertion height. Relevance to industry This study provides the lifting strength data for one-handed and two-handed manual lifting tasks. Practitioners can use the results of this study for ergonomic design of manual lifting tasks and equipments in industry.