Odd, but supinated and neutral grip PU do not strain or place any discomfort on my elbow but pronated do, especially if I go slightly wider than shoulders or wide or scarecrow width for BFKPU.
I was playing around with this on T-day break in LA since my brothers have a pullup bar on their door (IronGym).
My left elbow has been bothering me for a quite awhile. I believe it stems from an armbar during training but well, that's training.
A lot of straight arm work like Back Levers or Wide Arm HS holds or Rings turned out support/dips can bother it.
These pullups were performed strict, not kipped though BFK PU during WODS generally toast my left elbow for awhile.
My left elbow tends to seem have a limited of volume before I just don't go on further. It has now become an annoying pain in the butt.
Thoughts, and Steve Low thinks it might be a lack of flexibility in the shoulder which is somewhat tight based on wallslides performance.
I think quite possibly the problem has been, besides the armbar in question, is that I have the ability to do wide-arm L-PU/Bulgarian PU or bulgarian/RTO dips, rope climb without legs, 2 rope climb (but not as well as I would like) but maybe it's just too much.
Support with the rings neutral doesn't bother it nor does MU.