Get a solid magnesium supplement, or start eating a lot more cashews (high in magnesium).
Basically magnesium is the "off" and calcium is the "on" for your muscles...get low on magnesium and calcium floods in = cramp.
Recommend jigsaw health's b/c its chelated and time released, meaning much more actual absorption than the cheap stuff at your local supermarket. (no financial interest in their products btw...) (
Sustained Release Magnesium Supplements | Jigsaw Magnesium w/SRT | Jigsaw Health)
The majority of people in the US are magnesium deficient and athletes tend to be even worse.
As a bonus, your cardio will likely shoot up from restoring your magnesium to proper levels...have seen studies showing that, and tested it on myself as well.