you really think your bicep needs a whole week to recover ? do your curl 400 pounds for reps and do 30 sets ,, do you cause that much homeostatic stress to that one muscle that it really needs a whole week to recover ??
highly unlikely . look the reason the whole "one body part per week" idea really got started was because big bad mother fuckers that bench press 500+ pounds for reps set after set after set really did need a whole week off to recover their chest from that type of load .. but all you average guys like me that bench 315 we do not cause that much homeostatic stress and really do not need that whole week of recovery ,, we will be ready to hit chest again in a couple days. (but again if your a 290 pound monster benching 500 , go ahead and take that one body part per week approach cause you need it)