I'm using a 50 pound dumbell. I do 5 reps of 5 sets. I could only lift it up once or twice on the first set but do use my other arm to help lift up the weight on the remaining rep. On set 2, I could lift it up at least once but use my other arm to help lift up the weight on the remaining reps. Sets 3-5, I always need to use my other arm to help lift up the weight. Am I doing this all wrong? I was told about lifting the heaviest shit for at least 8 to 10 reps, 3-4 sets only if I want mass. What I read, Schwarzenegger said 5 reps of 5 sets of the heaviest shit for biceps. Should I use an arm curl bar to build both arms at the same time once instead of separately working out each arm with a dumbell which actually takes longer time?