Firstly, you do not have the responsibility for the performance and results of the men in your charge...that is their responsibility.
Secondly, don't ask them to go to the gym you woooss...tell them to go to the gym.
"Commanders must be quite clear that they have a continuous responsibility for the well-being of their subordinates, and that any disregard or abuse of that responsibility amounts to neglect."
http://www.army.mod.uk/servingsoldie...html#integrity
Sure, I know its 'only' army, but hey. Perhaps your version would read: "Commanders may be occasionally reminded that they have variable levels of responsibility for the well-being of some of their subordinates, and that occasionaly, disregard or abuse of that responsibility might possibly amount to neglect."?
I'm quite happy at telling men to go to the gym. Its just that in the Regiment, I didn't have to do it all that often.