Standing tall in a sport once dubbed "boxing with rackets," Nicol David has a better analogy to define the particular rigors of squash.

She calls it "physical chess" -- a test of body and mind in equal measure which the 29-year-old has mastered like no other female player since 2005.

The Malaysian has deployed that magical mix of physical prowess and tactical awareness to win seven of the last eight world championships, becoming the undisputed queen of her sport despite her slight stature.

"Squash is all about dimensions," says David, who is only 1.63 meters tall and weighs in at just 50 kilograms.

"You are sharing the same space as your opponent, and not many racket sports have that element in their game, it's really like you and your opponent being in a gladiator ring," she told CNN's Human to Hero series.

"It's all about taking your space and control and using the space as well as you can, like physical chess."

Top-level squash is played in a glass walled arena of just under 50 square meters of floor space and there is nowhere to hide. It adds to the sense of the theater for the spectators, but is a daunting prospect for the players.

"Going in to the glass door and getting ready for battle, it's very, very intense," David says.

Despite her small frame, she packs the punch of a heavyweight as opponents are dispatched in double quick time -- and has earned the nickname of "the Duracell Bunny."

It's easy to see why.

On the court she is the epitome of perpetual motion and, like the figure advertising the long-lasting battery, she never seems to run out of power.

But it is also her mental strength that has helped her win the world title every year since 2008.

"It has really helped me in the last few years, all the visualization we do, and also setting a game plan that makes me certain that on court you just need to be ready for anything and stay on top of things straight away," she says.

Dream fulfilled

David was set on the course for squash stardom from an early age, playing her first games in the city of Penang when she was just five, encouraged by a sporting father and two elder sisters -- Lianne and Cheryl -- who both played to national standard.

From her early teens, David was recognized as a prodigious talent and her first world junior title in 1999 signaled a further breakthrough.

But the step up to the senior level proved a testing time and in 2003 she moved to the Dutch capital Amsterdam to work fulltime with Australia's former world No. 2 Liz Irving.

It has proved a formidable partnership, and David is quick to recognize the part Irving has played in her incredible success.

"I've learned some much from her, she's just been a true mentor for me to show me what's it like to be at the top."

Under Irving's guidance, success at world senior level first came in Hong Kong in 2005.

"It's everyone's dream to be world champion and when it actually did happen, I was just standing speechless. I could hardly imagine my dreams had been fulfilled," David said.

"I still have that same exact feeling when I won that world title because it just means so much to me."

To have stayed at the summit of her game since then underlines David's incredible appetite for success.

"If you are technically sound and really fit and strong and mentally strong, you can be a top squash player," she said.

Intense training