So I'm preparing for this year of XC and I'll be capping out at about 50 mpw. I figure if I add anymore to this in mileage, I'll be injuring myself (Already bumping up a good amount). So I've looked to other methods for increasing my fitness gains before season starts. One of the methods that's easiest to do (I have a pool) is swimming. I have no experience with swimming training though, so I need some direction. Should I do intervals, or continuous swimming? If intervals, how many, how far, and how much rest? If continuous, how far/long? Lastly, how many times a week can I do this? Would I be okay doing it 4x/week?
Sorry for all of the questions, but I'm really clueless in this area.
TL;DR:
Incorporating swimming into X-training, running 50 mpw, what's the best way to do this?