The last weeks I observed couple times that I am getting stiffness/muscle ache in the upper arms after a boulder session. What's special about this is that it is very delayed. For example I went to the gym yesterday in the evening. Today I had no problems at all while working on the bureau. Arriving at home tonight an intense pain in the upper arms starts. Sometimes the stiffness even comes two days after the boulder session.

I am not facing cramps during or after bouldering. The issues I have while climbing are the typical hard forearms, lacking strength in the hands and skin resistance. No problems with the upper arms while climbing.

When I am facing muscle ache after an exhausting endurance run or a soccer match they come directly after the sport or by no later than the next morning. Therefore I am really wondering what is going on here?

So besides the general opinion that my body needs minerals like magnesium/calcium and lots of liquid what would you suggest?