Sept 10 (Reuters) - Manchester United forward Cristiano Ronaldo is capable of playing until he is 40 as he has adapted his playing style to extend his career, former captain Wayne Rooney said. Ronaldo, 36, spent six seasons at Old Trafford between 2003-09, winning eight major trophies, and rejoined United from Juventus last month on a two-year contract. "His ability is obviously one thing, but then he's also looked after himself massively ... he's still in great condition. It wouldn't surprise me if he's playing until he's 40, like Ryan Giggs did, and still scoring goals. Ronaldo, who scored 118 goals for United during his first spell, is expected to feature when they take on Newcastle United in the Premier League on Saturday.
