well ive only started back to lifting like 2 weeks ago.. an i been trying to do Bis the same day as back.. so i start off with back an when i get to the biceps.. they are pretty tired an im not able to do a whole lot of reps or weight.. i feel like they are getting a half ass workout... should i just split the arms into a separate day or should i expect them to get accustomed to it after a while