I'm pretty sure that if you are violently vomiting, a calf cramp would be a secondary worry, no matter how severe. The brain can only process so much at one time.

I'm kidding though, I'm sure that's not the reason it works. This article is being discussed all over the place right now and it amazes me how common it is that pickle juice is used at all kinds of sporting events. Road races, HS wrestling, football games, etc. I had no idea it was so popular!

I've also seen it mentioned that you can use raw organic apple cider vinegar in the same way.