solution

A job requires a 20 lb. box to be lifted from a platform 5 inches above ground to a shelf through a vertical distance (D) of 20 inches. The expected frequency of lift is 60 times per hour for a 2-hour period. At the origin of the lift, the load center of mass is 10 inches away from lumbar spine, and at the end of the lift the horizontal distance is 20 inches. While performing the lift there is a 20 degrees angle of twist of the trunk from the medial plane. Assume the coupling between the hands and the box is good and all other assumptions of using the NIOSH lifting guideline are satisfied.