Weird forearm temporary injury where muscle "locks up" in bicep curl motion - rolling over itself?

This is hard to describe, but wondering if anybody has faced anything similar.  I don't know exactly what it is causing it or the exact movement that's causing it, but it's happened in 2/3 of my last trad outings, yesterday it happened the worst and in both arms.  After some particularly strenuous crimpy corner movement the muscles in my forearms are "locking up" in a 90 degree bicep curl matter.  It feels that a muscle has rolled over itself and it prohibits any additional "bicep curl" upward movement until I apply some pressure on the forearm muscle and release it. I thought particularly odd that it's happened in both my arms....

I was doing some pretty strenuous lockoffs on the climb before...so maybe that's contributing to it.

Regardless, I was able to climb normal the rest of the day after the muscle rested a bit.

I think that is elbow tennonitis. Dehydration plays a factor too. 

Does it happen in your sport outings, or only your trad outings? You might need to do some sport outings and report back for a proper differential. 

See an orthopedist.

I have had a similar experience where I could bend my elbow to 90 degrees but had a hard time straightening it back out. I even had to use my other arm to straighten it. I was pulling the excess slack to put my second on belay. This was a couple days into a trip to red rock and I contributed it to fatigue and dehydration. 

If you are describing more of a cramping sensation in the back of your forearm (Posterior or aka the side that the back of your hand is on) during flexion of your elbow then it is probably your brachioradialis muscle cramping from dehydration; you find that you will cramp more with a pronated forearm while flexing the elbow (the position your forearm is most commonly in during climbing).  If this is what you are experiencing then you need to make sure you drink more fluids throughout the day. I find that "pre-loading" myself the day/evening before by drinking lots of water helps to decrease dehydration the day I am climbing; I've found that drinking a pedialyte the day before helps also. 

Sucks pretty bad when you're on a runout and the dang forearms start cramping again!!!

Choss Wrangler wrote:

If you are describing more of a cramping sensation in the back of your forearm (Posterior or aka the side that the back of your hand is on) during flexion of your elbow then it is probably your brachioradialis muscle cramping from dehydration; you find that you will cramp more with a pronated forearm while flexing the elbow (the position your forearm is most commonly in during climbing).  If this is what you are experiencing then you need to make sure you drink more fluids throughout the day. I find that "pre-loading" myself the day/evening before by drinking lots of water helps to decrease dehydration the day I am climbing; I've found that drinking a pedialyte the day before helps also. 

Sucks pretty bad when you're on a runout and the dang forearms start cramping again!!!

You described it well, however I felt the cramping on the inside of my arm, looks like the brachioradialis muscle also spans to the inside of the arm as well.  I bet that was it.  I don't get many other muscle cramps throughout my body, but this one felt more like my arm was "locked" almost like the muscle just stopped working and / or was rolled / twisted for a moment.  If that's what a cramp feels like then dang..that's crazy.  

This happens to me when I'm dehydrated and tired but still trying to push myself.