Its not that stiff IMO, just really headlight. If you are worried, use a soft string, dont go BG80. Maybe drop the tension a tiny bit. One thing I must mention is not to give it up too fast. To really use it I think other than adjusting swing, there must also be some tactics adjustment to use the NS9900 properly and abuse its superfast headspeed and minimize the effects of crappy outright power. I went from a medium balance racket to NS9900, and its opened a few doors, while closing a few. The points have become a bit longer (fun!), since harder to smash them out, but also harder for them to smash me out. Its really really really fast, so you can stand a bit closer to the net when defending, which allows you to better counterattack or play a transition kind of shot to try to get the initiative back (shuttle is higher). Its easy to quickly slow down the head and not very bouncy, so nice to play double/triple deceptions or soft tight net shots. The last time I switch back to my old racket I got hit in the face . Was standing near the front as usual, and when the shuttle smash comes i tried to raise my racket, but it was in slo-mo. Full-power arm smashes are kinda wasting time IMO with this racket, and may even be a cause of the injuries mentioned since the racket goes too fast for the arm to keep up (a bit like driving a car in 1st gear). I think you really want to use maximum wrist snap while making a special effort to push the racket head through otherwise the head will slow down alot on contact. The headheavier rackets dont slow down nearly as much. Also, dont expect to one-shot people from the backcourt, probably better to aim for accuracy and better recovery and be prepared to use 3,4,5 pointsmashes/drops (easy to get decent speed, and its really accurate cos headlight and stiff) to work your opponents out. Even if it goes a bit wrong and they manage to counter you should be set for the drive wars and will have a good defence. Flatshot drive wars should be quite good for you, also you can go forwards more and maybe even throw in the drop (easy to do). In general the more you can get the shot frequency (less time between shots) up the better you will do.