Very interesting. Thank you travlerajm for this wonderful info. I feel enlightened about racquet tuning. Before this, I would just get dozens of racquets and demo them and choose the one that felt good. I am happy to report that the ones I have chosen have passed the MgR/I test and vice versa for ones I didn't like. About swingweight I understand that high weights benefit professionals but I think it's worth noting they train hours every day, developing strength and advanced technique to make swinging them easier for them. They also have balls coming at them at a much greater speed. My feeling is that really heavy racquets may possibly be detrimental to performance for club players if swinging them becomes difficult and that sufficient stability can be achieved with slightly lighter racquets given the slower paced balls they have to deal with. Somewhere in the threads you mentioned you were writing a book on this subject. I was wondering how that is coming along and would like to express my enthusiasm at obtaining a copy when it is complete. Cheers!