“…and by halfway through the second day my elbows were killing me.”
“…is this common”

It is not common with lightweight poles. Also, forearm fatigue is not common with lightweight poles (though you didn’t mention it, I just thought I would throw that into there).

I’ve enjoyed my 2.4oz poles from GG: http://www.gossamergear.com/cgi-bin/gossamergear/Lightrek3_Trekking_Poles.html

-Barry