Entering the age of attitude adjustment

The Williams sisters and Roger Federer are proof that being on the north side of 30 is no barrier to success on the tennis court - but they have had to adjust to stay on top.

More than 40 players at this year's Australian Open are over 30, with Japan's remarkable Kimiko Date-Krumm the oldest at 44. She played her first Grand Slam in 1989.

Others still going strong include Francesa Schiavone, Vera Zvonareva, Daniela Hantuchova and Zheng Jie.