Running and swimming are as different as night and day- one is weight bearing, one is not. One uses the upper body significantly more than the other. Muscle recruitment is different. And so on.
Amy Burfoot, a one-time winner of the Boston Marathon, gives this colorful account in runnersworld.com of how he mastered swimming a mile non-stop.
Amby went to Total Immersion creator Terry Laughlin for guidance.