I mean each group twice a week. i.e.
day 1 chest, tris, shoulders
day 2 back, bis, abs, forearms
day 3 legs, glutes
day 4 1
day 5 2
day 6 3
day 7 rest[/quote]
If I understand you correctly, you are working out six days in a row without taking a break. If that is correct, you need to insert a rest day between day 3 and 4. If you are working out with sufficient intensity, your body needs a break every few days in order to recover. Remember, just because you aren’t working the same muscles every day, you are working your nervous system. Recovery is critical.
But I suspect overtraining is not really the issue here. As a solution to stalled progress, I think instead of increasing frequency, you need to focus on increasing intensity. You haven’t given much indication of how you train, but by your training frequency, I would guess you train lighter weights with high reps. I would suggest lifting weights 80-95% of your max in low rep (3-5 reps) sets (5-8 sets) on the core lifts. If you are lifting hard enough you will soon realize the importance of recovery.
To sum it up, don’t lift more often LIFT HARDER!!!