I've recently started working out again (2 months). I started doing a light full body work out 3 times a week. After getting into a routine and figuring how to fit it in (and, honestly, just seeing if it was something I wanted to stick with), I decided I wanted to chang my workout to add some mass. I met with the trainer at golds and he set me up with a work out plan for 3 days a week. Chest/triceps, back/biceps, and legs/shoulders. I'm working abs every workout. Question I have is, he has me doing lat pull downs, which hit the target muscle, but my arms are giving out before my lats do. I can tell my lats still have a lot of work left in them, but I just can't do another rep. Am I doing it wrong? Thanks in advance