Yep. Other fitness doesn't translate back to the pool for some annoying reason.

In HS, the guys on the track team used to call it "swimmers' legs." If they tried to keep swimming competitively, they said it deadened their legs for sprints. Totally different use of the leg muscles. I never had a problem doing swimming and long-distance running, but I never tried to do sprints. But it is a very different use of the leg muscles. Likewise, most lifting routines are a very different use of the upper body and arm muscles. It is hard to design a lifting program that will increase (or even maintain) swimming performance. I think it is best to keep a well rounded approach to swimming and running and/or biking. I swim freestyle almost exclusively, which doesn't do much for my legs, so I really benefit from a lot of biking, especially long and steep hill-climbs. I find the two very complementary and would not want to focus one one to the exclusion of the others. I can't run anymore or I would also do lots of that--it was my first love. They are all great for cardiorespiratory fitness but very different muscle mechanics.