I was just at the lake for a swim. I ended up getting such knots/ cramps in my stomach (high like just under the rib cage). If I do sit ups or some strain like getting out of a kayak it can occur and it is concerning because you really can t move until you try to message or press on it a while and breath. I do get really good leg cramps occasionally that will drive me out of the bed and hobble around. I was hydrated, plenty of calcium I am of average or lean weight, healthy, eat well, I do not take anything I am 59 years old. in all other regards work, active etc. etc.