Two words on this Lee Iacocca. If you can't do what those you manage do, it is nearly impossible to properly allocate work. Also when crunch time comes you are unable to jump in and keep things running, a critical part of leadership. Before Iacocca took over at the helm of Chrysler he had done nearly every job in the business, and quickly secured the trust and buy in from the UAW that was critically needed to put the whole 80's bail out together and make it work. The line people respected him because they knew he had been one of them in the past. This should be mandatory for line managers.