Would it be better to do chest and shoulders in the one session or back and shoulders? Also should muscle groups like arm and chest be the single focus of a session or would it be ok to combine arm/chest in one session?
If your doing a split routine, then you could do your shoulders with chest as some chest exercises work the shoulder also. I wouldnt just focus your arms in just one session either, as that would mean you doing too many isolation exercies.
