Consider a worker standing on the ground lifting crates of vegetables (10 in. high and 10 in. deep, 30 lbs) from the ground to the flat bed of the truck where another worker will move the box and position it properly in the truck. Assume that the lift from the ground is fairly optimal, but that the reach onto the truck is fairly bad at a horizontal distance of 20 inches. How many crates per minute can he loaded for an 8-hour shift so as to be acceptable according to NIOSH guidelines? Redesign the job, so as to maintain the expected quota of 10 crates per minute but still keep back strain to acceptable levels. Would back belts be an acceptable control measure? Why or why not?