Liberty Mutual Manual Materials Handling (LM-MMH) Equations

Developed by: Liberty Mutual

Description: A scientific publication that summarizes 40 years of research done at the Liberty Mutual insurance company to predict maximum safe lifting, lowering, pushing, pulling, and carrying loads for males and females. The resource presents fourteen different equations in section 3 (“Results”) for users, with a description of where they came from, how to use them, and a rough indicator of accuracy. Each equation considers worker sex, durations and frequencies, as well as task-specific features like distance lifted, distance carried, and whether pushes/pulls are sustained or not. The resource provides an example calculation; users must implement the equations themselves.

Keywords: push, pull, lift, lower, carry, burst, sustained, initial, limit, safe, recommend, equation, hand, back, shoulder