research shows that the order of exercises can significantly affect strength development so it is standard practice to set up a resistance-training routine to work large muscle groups before smaller ones. the reason is that a small muscle group that fatigues first will be the weakest link in the chain and prevent large muscle groups from working to full capacity. for example if you isolate and fatigue your biceps muscles with curls and then try to do lat pull-downs (which use biceps shoulders and back) you won't be able to do as much work for your shoulders and back because your biceps will already be fatigued.
how important is the order in which i perform my exercises?