I did 5 sets for DL today and during the last 2 I noticed my triceps felt sore. Like I've been doing tri extensions or something. Clearly I'm doing something wrong so since I have no one to ask in person, what could be causing this?
Do you train triceps directly? if you don't you need to, or they are tight and need to be stretched.
Your lats as well as your teres major attach to the humerus deep to the triceps. That is likely where the soreness is and you are just mistaking it for tricep soreness. Those muscles are both indirectly involved in the DL, so it's not surprising. I get soreness in this area if I do alot of heavy rowing or pull-ups/pulldowns.