So I'm considering buying a training racket to improve my strength a little. I expected them to be cheap, but they're actually a little pricier than expected with the Yonex one reaching almost £45. -Would you guys rate training rackets as worthwhile? -Do you own or practise with any training rackets? -Could training rackets not effect your timing/make your timing poor with a faster racket? -Are they worth the money? -Which training racket would you recommend? -What sort of string tension should a training racket be used at with plastic? 20lbs? Thanks in advance!