Here is part of my leg workout. Now what percentages of my one rep max should I do for sets 1-4. I tried doing 50% for set 1, 70% for set 2, 75% for set 3 and 80% for set 4. However, I was pooped by the middle of the second set and I couldn't do anymore after that. So I am asking what percentage of my one rep max should I do for each set. Also, is the first set a warm-up set?