Last spring I was reading a book called "The Brain That Changes Itself", by Norman Dodge M.D.. It's mostly about revolutionary techniques being used to rehabilitate stroke and brain-damage patients, but much of the neuroplasticity advice could apply to the rest of us in everyday life, especially when learning something like swimming.
I experienced a little of this neuroplasticity when I developed nerve problems shortly after making the switch from manual to CAD drafting back in the mid-90s. After having to learn to work left-handed, I discovered that other activities (using a screw-driver etc.) became easier with the left hand as well.