i do competition swimming and yes it is the best, and yes it does stress out your shoulders.i actually prefer to do weights after swimming because lifting isnt a huge part of swimming. Like any other sport, you need to do it because it helps alot, but its not 100% necessary.I do mainly freestyle, i do the 50 and 100. but like they said, mix it up. oh and when i do weights i usually stay away from shoulders on swimming days, or ill maybe do my left shoulder, to keep it as strong as my right, if you use one arm too much, it sucks, trust me. If you just starting do a 100 warm up of each exercise, then do routines from there. My personal opinion to being a great, fast swimmer is to have extremely strong shoulders and legs (mostly quads). And having a strong chest and lats are also very helpful. So during the off season, id work my shoulders and quads more than anything. Also, train for endurance, not size, i have big legs but there just really weak i cant explain it so i have to mostly rely on my upper body. Dont let that happen to you.Being that this is only my second year swimming and weve only had one dual-meet so far, im not swimming all that fast, but here are my times from our first meet anyhow, set them as your goals too, because im only 16.
50 free-28sec.
100 free-1:08 i think (ouch...)
100 breast-1:32 i think (mega ouch, im new at that)
And our next meet my coach said hes put me in the 100 fly, which i cannot do, it is hard and ive never racedit before so im screwed. but anyhow good luck with swimming and you will see massive, and i mean massive, gains in your endurance as the season goes on.