How to do a bodybuilding 45 minute back workout

Here is a killer 45 minute back workout that you can do at home with just a set of dumbbells and a pullup bar. This is a back (lats,latissimus dorsi)workout for the advanced bodybuilder. Make sure you have done warm-up sets for both biceps and triceps before starting this workout because we start in with really heavy weights and you don't want to get injured.