[KSig RC]

It's pretty easy to mistake foot/calf/lower leg "cramping" with simply "soreness" - especially if you don't work out a lot, the culprit could be something much simpler than salts ... anything from improperly fit shoes to improper technique to difficulty getting loose.

Start from the ground up - if you haven't before, look at the wear pattern of your shoes and find styles that are designed to fit your footstrike. Next, get properly fit for a good pair of shoes that fit what you're using them for. Even something like moving from a "padded" running shoe to a "stability" shoe (think Asics Cumulus to Kayano) can make a huge difference in the pressure put on the foot and the small muscles of the foot/lower leg.

Try low-impact exercises as well, and build up slowly - this may help the muscles strengthen, particularly smaller 'support' muscles. Don't bite off too much at once. Things like yoga can really help too, increasing stability and working those muscles that don't get worked in normal, everyday tasks.

Once you've eliminated the mechanical or equipment issues, you can also work with a PT (or possibly very specialized trainer) to design a program to work around the cramping, too - but it may be easiest to start with the easiest things to change, and hope to get lucky. Good luck!