i recently moved from VA to WA to live with my dad. in VA i had a weight set with dumb bells and a barbell. for bicep curls i did 10, 15, 20 each arm with dumb bells. but then i go to WA and i have a cable machine there. i do the two-handed bicep curls with the cable machine and i can barely do 10, 20, 30 with two hands! can anybody explain why that is?..... thank you.