well, yes it does as it's harder work on the arms than swimming without paddles, but for upper arm wobble do tricep stuff -i guess you know that for toning do high reps low weights, but for bulk do low reps high weights? If you're coming back to swimming after a long lay off, don't get annoyed, it'll be a while of feeling cr#p and slow, but it'll come back quickly once you get past the initial cardio fitness bit.