recently i have started to get serious cramps in my quads and hams when swimming.
it occurs when i push off at the start of each length.
i have read and been told that i may need salt tablets to aleviate the problem as i may be dehydrated, (even though i drink large amounts of water all day, and sports drinks while training).
i have also read that along with sodium i should be taking magnesium, potasium and calcium (calcium and magnesium are present in a one a day multi vitamin that i take, it doesn't say what quantities though).
i would imagine i would be hard pressed to find one product containing all of the above mentioned, but some advice on where i could purchase all of them would be welcome, as would advice on other supplements that may be of use to me.

I'd be inclined to doubt that your sodium's out of whack if you're drinking sports drinks while training - they contain a fair amount of sodium, but you might want to switch to one of the newer drinks for endurance athletes, which have more sodium in them. Try Gatorade Endurance, I think it's got like 330 mg of sodium per serving. As for potassium, you can get lots from potatoes and bananas, and the calcium / magnesium tablet you're taking should do the job for that part.

Leg cramps are commonly caused by low levels of calcium, so that'd be my first suspect. Make sure you get calcium from your diet as well, because a lot of calcium tablets are hard to absorb and not as easily utilized. Dairy, man!

Hopefully this will all help. Good luck!

I have the same problem, but don't drink sports drinks. I just started using Nuun's (a little effervesant that you drop in your water bottle). It has most of what you mentioned in it and tastes really good. Not strong at all, quite refreshing. It's worth a shot, although it sounds like calcium might be your problem.