You would run an unpowered signal (as Waldo said) up to the stage - put your power amps close to the stage, and then you can run the cables from the amps to the speakers pretty easily.
There's a couple of advantages to this:
- noise - as waldo also mentioned. a long run of powered cable is susceptible to noise and signal loss. It's better to keep them as short as you can get away with.
- snakes commonly come setup for this - without speaker cable runs in them. Often you can get them with 1/4" balanced lines that are used for sending the unpowered signal. you can get dedicated separate speaker cable snakes if you really need to do this.
- speaker cables are pretty expensive - long runs of speaker cables cost quite a bit.
All that said - if you have to settle for one that just has XLR connectors, you can get adapters to go from XLR to 1/4" to run whatever you need. If you order one you should be able to get one with 1/4" runs in it though.