1 Seated curl to standing dumbbell curl
A seemingly minor change that has paid off immensely for me was to stop alternating sides when curling with dumbbells. When alternating, I found that just holding the dumbbell while the other side was working really took a toll on my forearms. My grip strength would fail before my biceps did.
So now I do 15 reps seated for one arm without alternating, then stand up and continue with another 15 reps standing up with the same arm. Only then I do start with the opposite side.
2 Preacher curl to standing EZ-bar curl
Because I’m seated, this is a very strict movement in the beginning. That also limits the amount of weight I can use. With preachers, I go with a very narrow grip, and I don’t go all the way down because I find it puts too much stress on the biceps tendon.
With a shorter range of motion, I work on pumping and squeezing the biceps as much as possible. Then, when I finish the first 15 reps, I’ll transition to a standing position and use a wider grip. I’m using a little body English now, so I get some help to keep the set going. If I’m not totally gassed by the time I approach 15 reps, I’ll add in a few slow negative reps to make sure I hit failure when I should.