Yeah, that's useless...that even goes beyond high rep schemes for endurance training. You're just shredding muscle tissue at this point.
Stick to reps in the 6-10 range, and vary it. Do 6 reps for a few weeks, 8 reps for a few weeks (same weight if possible) and then 10 reps. Then drop back to 6 reps, and up the poundage, because you should be stronger AND bigger by this point.