Kim Clijsters on her second comeback, motherhood and being an inspiration to others

Kim Clijsters says the guilt of being a mother competing in top level sport has assuaged as she prepares to return to tennis at the age of 36.

The Belgian, a former world No 1 and four-time Grand Slam winner, is quietly building towards one of the most unlikely sporting comebacks in history.

Seven years after quitting tennis and now a mother to three children - Jada, 11, Jack, 6, and Blake, 3 - she believes she can still compete with the best players in the world.

"Some people think I'm mad but to me it feels fine because I'm following a feeling," she said. "Something got triggered and I'm following that emotion. I wouldn't be able to do it if I felt I was pushing myself. But I have to believe I can do this."

Clijsters had intended to return at the Australian Open this week but was delayed by a knee injury and will begin what she is calling her "third career" in March.

She is already the architect of one of the greatest sporting comebacks of all time.

In 2009, after two years away from the Tour - during which time she gave birth to her first child - she decided to return.

The tennis world was stunned when she won the US Open in her third tournament back as an unranked player, lifting the trophy while cradling daughter Jada in her other arm.

"I remember when Jada was younger and I had to go to practice and she would be crying at the glass back door and I would feel guilty," she said.

"You lose a bit of that guilt as your kids get older and the more kids you have. Now I'm a bit older and I leave and the kids are at school. They don't know I have hours of practice, because they haven't seen that and their schedule hasn't really changed.

"I can now talk to Jada about whether she wants to travel with me. And she'll say: 'if the hotel's nice and there's a really good breakfast, I'll come to the tournament'."

Clijsters, who runs a tennis academy for young players bearing her name, has always preferred to live a quiet life and certainly does not court the fame which inevitably accompanies her success.

She was raised in the city of Bree in the Flemish region of Belgium, home to around 15,000 people and still lives here with husband Bryan, a former professional basketball player, and their children. It was not Clijsters' intention to be viewed as an inspirational figure to other mothers but she says that is a happy part of the venture.

"I think if it happens naturally, that's great," she said. "When I think of women I look up to, it's when I feel there's a passion behind what they're doing. In the past when I started playing again after I had Jada, I got letters from women who were inspired.

"I've got women who come up to me now who say they started running because of me. I'm sure there's other women who think, 'why can't you just stay home?' but I was just mum for a long time and it feels good to come back and know that the kids aren't too impacted by my decision. I want to be able to go running, play paddle and do basketball in the back yard."

Some coaches of rival players have cast doubt on whether Clijsters can cope with the increase in power in the women's game since she last played. But she points to the likes of Serena and Venus Williams and Roger Federer as examples of why tennis is an older person's game presently.

"It certainly seems to be that way," she laughed. "I do feel that I have improved but it's been so many years that it's hard to compare to how I felt when I was 21 years old. I'm sure I was a lot quicker, my reactions were better and my eyesight was better."

Does she still believe she can win tennis tournaments?

"I don't know," she said. "But I would like to see if it's possible. I want to see how far I can push myself. I have to believe I can do it, I have to keep pushing."