I'm hoping that someone can make a suggestion or give me some insight.
I have started getting cramps in my calfs (calves?) and my hamstings in the afternoon and at night. The soreness lingers for 24-36 hours. The cramps never have occurred while riding and usually occur on my off days. I have been regularly recreationally riding (75 miles a week+/-) since May and not overstressing so it's not a change in my routine. Even though it's very hot in the North East, I make sure to hydrate. The other day I'm reading in a coffee house and suddenly my hamstring seizes up. This morning I awoke to my calf on fire. I'm getting very frustrated.
Any thoughts on why this is happening and what I can or should do to stop it.
If the cramps are happening on off days, I'd be suspicious of nutritional factors. Any chance you're deficient in E, Calcium, Magnesium, or Potassium? I'd suggest googling "muscle cramps" and some of the aforementioned vites/minerals, giving preference to scientifically authoritative sites and avoiding those with something to sell. Good luck!