On some of my muscles specifically biceps and shoulders my strength seems to dwindle as the exercises progress. I'll be precher curling close to 40 each side, but when I'm down to my last exercise (3rd) for biceps I'm doing single dumbbell curls of only 25 and not having the easiest time. However if I start with dumbbell curls, I'm doing 40s. Does this mean my body probably has a higher composition of white fibers than it does for red? Orrrr I dunno guys I'm stumped, any answers? I understand you'll never be as strong as your first exercise but 15-20lb drop off for biceps in your last exercise is a lot when you think about it...close to 50% less.