I have had a fair amount of physical jobs. Warehouses, factories, and construction. One thing I've tended to notice is jobs that pride themselves on being super physical are either A. Lacking equipment, B. Have Poorly thought out production flows. Rather then using conveyer belts, forklifts, carts, etc they just throw a bunch of manpower at a problem. People constantly get injured, or it slowly wears on you until you're basically disabled.
The employees will talk about how you have to be super strong or tough to work there. I worked at a tire distribution center for awhile. The pickers would bring the pallets to the trailers. Then we would stack them one by one into the trailer. It just seemed incredibly inefficient. Why not just put the tires on pallets, or in bins then onto the trailer? These places also can never keep a full staff.