Related Program: Morning Edition Polyester Strings Put More Spin On A Tennis Ball By editor • Aug 30, 2011 Related Program: Morning Edition TweetShareGoogle+Email Great tennis legends used to use heavy wooden rackets. Graphite arrived about 25 years ago. Since then, the technology hasn't change much. That is until now. More and more pros are using polyester strings in their rackets. TweetShareGoogle+EmailView the discussion thread.