Yup!!! Thought id try it out in my Ai98 (quite a soft, muted racket) at 53lbs. Instant arm pains!!! No play for a week. Gave it a hit yesterday and it does seem to have become more playable...but only slightly. Spin can be outrageously good with it but its just a killer for the arm sadly. Poly Tour Spin still my favourite. Has anyone tried the YPTSG under 50lbs?