Basketball star Yao Ming announced his retirement on Wednesday after a

trailblazing career that made him China's best-known athlete and helped

spur the game's global growth.

The towering 2.29m star made the

announcement, which had been widely expected, during a press conference

in his home city of Shanghai after his last two seasons with the Houston

Rockets were dogged by injuries.

Yao, 30, said he had "waited and hoped that I could return" from a broken foot last year.

"It

was a frustrating period and many thoughts crossed my mind. Today I

would like to announce my personal decision to formally retire as a

basketball player," he said.

Yao added he planned to focus on his

role as owner of the Shanghai Sharks, the team where he started his

professional career and which he bought in 2009.

The NBA

All-Star, who has used his fame to confront Chinese taboos ranging from

the treatment of people with HIV to boycotting shark fin soup, said he

would also promote philanthropy in China.

In a choreographed news

conference, Yao stayed composed as he stood at a custom-made oversized

podium and recalled receiving his first ball at age four and donning his

father's old number at 16 for the Shanghai Sharks.

Yao then

joined the Rockets as the first pick in the 2002 NBA draft amid

scepticism about whether the signature product of China's massive state

sports system would ever earn the affection of the league's fans.

But

he won over Americans and became an adored national icon in China

through his strong play — when fit — and his grace and poise. He was

not China's first player in the NBA, but he was certainly the

best-known.

He exhibited that same grace during his retirement

announcement, switching to English to offer a "special thanks" to the

city of Houston.

"I would like to thank you for giving me a great nine-year career," he said.

"Nine

years ago I came to Houston as a young, tall, skinny player and the

entire city and team changed me into a grown man, not only a basketball

player."

Although his size was his strength, the rigours of

top-flight basketball proved too much for Yao's massive frame and his

career has been marked by lengthy absences from the court due to a

succession of mostly foot and leg injuries.

Nonetheless, he was China's first global sports superstar with a personal brand valued at more than $1 billion.

The

eight-time NBA all-star routinely tops Forbes' list of China's most

valuable celebrities and his international appeal has in the past led to

endorsement deals with Nike, Pepsi, McDonald's and China Telecom.

But

the brand he has done the most to promote is the NBA. China has become

the league's biggest market outside the US since he began playing with

an estimated 300 million fans.

Fans had already begun mourning

his departure as reports of his planned retirement emerged in recent

weeks and on Wednesday Chinese web portals set up special pages for fans

to pay tribute.

"For Yao, it's closing a circle. For basketball fans, it's a pity," Jason Zhu, a 28-year-old Shanghai civil servant, said.

NBA commissioner David Stern praised Yao as a "transformational" player for the game.

"Since

entering the league as the number one pick in the 2002 draft, Yao Ming

has been a transformational player and a testament to the globalisation

of our game," he said in a statement.

"His dominant play and

endearing demeanour along with his extensive humanitarian efforts have

made him an international fan favourite and provided an extraordinary

bridge between basketball fans in the United States and China."