I have been playing with my lighter Asian BLX 6.1 90's and my old Pro Staff 6.0 Original 95 and switched back to my old K Factor 6.1 90's. Its like hitting a turbo boost button switching back to a heavier stick. I can literally feel my opponent get pushed back by the weight of the strokes. They are almost surprised and wonder happened all of a sudden. If I can keep swinging my heavier racket without getting a lot more tired I will. If I get tired I'm considering going back and forth between the light and heavier rackets. The heavier racket takes a toll when I serve than the lighter racket. How many of you guys switch between differently weighted rackets ?