Back Muscle Strength and Weight Limits in Lifting Burdens

Abstract

When lifting loads, the muscles of the back, rather than the ligaments and the bony structures of the spine, should overcome the gravitational forces. Formulas, based on measurements of the back muscle strength for prediction of maximum loads to be lifted, have been worked out and tested in practical situations. From tests with 50 male and female subjects, the simplest prediction formulas for maximum loads were as follows: for men, maximum load = 1.10 X isometric back muscles strength; for women, maximum load = 0.95 x isometric back muscle strength minus 8 kg.