Last week I learned a fine tip from my personal trainer.
I had gone running 4 miles on a treadmill and then went straight down to the pool to do swimming with my personal trainer.
That is SO not a good idea!!! I got serious leg cramps about 4 laps in to swimming. I don't know what causes the leg cramps, but my personal trainer was telling me that it happens with him too.
So...just a word for the wise, if you're going to run and then go swim, take a BIG break in between. Spread it out. If I'm going to do this, I will run in the morning and then swim at night.