i had done back/bi, chest/tri, leg/sholder 2X per week. it took my about 4 years to realize i'd been over training. i went on a trip and didn't work out for over a week and when i came back was stronger than i had ever been. i didn't think a whole lot of it until i read an artical on signs you're over training.
now i go
Mon back
tues bi
wed chest/tri
thurs legs
fri shoulders
sat off
sun off.
i've grown more on this schedule than ever before. i love it