Williams sisters don't play enough: Navratilova

Los Angeles Aug. 10. For Martina Navratilova, the often-injured, often-absent Williams sisters don't have much staying power.

The 46-year-old legend, who is still going strong in doubles three decades after she began her career, said, ``even without an injury they've pulled out of more tournaments in a year than I did in my career.''

Navratilova, competing in doubles at this week's tournament in Los Angeles, speaks from experience as the winner of a record 167 WTA singles titles and 18 Grand Slams.

The ageless wonder suggests that top players should compete in at least 15 tournaments per season.

That's well over the average for Serena and Venus Williams, both looking in danger of missing the U.S. Open due to injury.

Serena is certain to be out of action during the New York event, starting August 25, after recent minor knee surgery, while Venus has been carrying an abdominal strain for four months and has not played since Wimbledon, when she lost another final to her sister.

It has never taken much of an excuse for either player to give their regrets to tournaments.

``I think they don't play enough, and the other women play too much,'' said Navratilova, who added that between 15 and 18 tournaments is about the right annual number.

Venus has managed just 10 tournaments in the last year while Serena has shown up at a dozen. In contrast, the hard-working Belgian Kim Clijsters, poised within days to take over the World No. 1 spot from Serena, had 22 tournaments to her credit.

Jelena Dokic has sometimes played 30 events in a 12-month season.