So, I started going to the gym about a month ago. Doing dumbell curls I started at 10lbs. I tried 50lbs at first.
Mistake!
Sized down until I got to 10lbs. I was looking for the first one I could do 20 reps. Then, as days went on, I kept moving up sizes. I’m currently at 25lbs. I keep wanting to move up to 30lbs, but my body gives way around the 12-15 rep range. So, not quite there yet. But the first 10 reps of 25lbs aren’t even hard anymore. It only gets increasingly more difficult after the 10 mark, but more often than not the 15 mark. 15-20 are the hard ones.
But with 30lbs it’s hard right from the start.
So, should I be doing the 30lbs reps, even if its less than 20 reps? Or do the 25lbs reps which I can easily do 3/4ths of before it becomes a struggle for the last few reps?
Anything between 5-30 reps is inside the hypertrophic sweet spot, but for isolation exercises you probably want to aim for ~12 reps and up.
My biggest concern reading this is that you seem quite fixated to the weight of the dumbells. Some body English is fine, but be careful to not make what should be a biceps exercise into a full body exercise.
Body English? :)