I am not aware of any information in the written or oral Torah which discusses what was involved in preparing Jewish army troops for battle, but I assume that soldiers would spar with each other and otherwise engage in physical combat to prepare themselves, similar to the battle preparations of other ancient cultures (e.g. Spartan Agoge). Assuming this is correct, what would the halacha be if one soldier injured another in practice combat? Would this follow the regular laws of damages? Would there be a dispensation because it is in the context of preparing for battle?
I assume similar issues have arisen in modern day Israel, I would accept an answer based on the halachic reasoning used in that context.