SHANGHAI, Oct 1, 2007 (AFP) - Shanghai kicks off the Special Olympics World Summer Games on Tuesday with a rousing opening ceremony to welcome a record 7,300 mentally disabled athletes to China's financial capital.

"All the preparations are completed and we are ready after five years of considerable preparations," Shanghai Vice Mayor Zhou Taitong told a press conference here on Monday.

Zhou, the vice chairman of the organising committee, said 7,300 athletes from 164 countries and regions, a record participation for the Games, would compete in 21 medal sports and four demonstration competitions.

The event begins with Tuesday's opening ceremony at the Shanghai Stadium, attended by the city's most famous sporting sons -- basketball icon Yao Ming, a Special Olympics ambassador, and Liu Xiang, the world and Olympic champion 110m hurdler.

Teams of athletes will march into the stadium to a theme song especially composed for the event by Chinese-American Tan Dun, composer of the Oscar-winning soundtrack for "Crouching Tiger, Hidden Dragon."

Flags, banners, and billboards advertising the Games have sprung up around this city of 17 million people while 40,000 volunteers are on hand at 30 competition venues refurbished at a cost of 66 million dollars to provide barrier-free access to athletes in wheelchairs.

"I know I can" is the slogan of the Games originated by Eunice Kennedy Shriver, the sister of John F. Kennedy, inspired by the life of their mentally disabled sister Rosemary Kennedy who died in 2005 at age 86.

She lived most of her life in an institution following a lobotomy at age 23 and Kennedy Shriver saw sport as a vehicle to improve the lives of an estimated 180 million people who share similar mental disabilities.

Special Olympics have been held regularly since the 1960s. In 2003 they were staged in Dublin, Ireland, the first time the Games were ever held outside the United States. Special Olympic Winter Games were hosted by Japan in 2005.

China, which hosts the Beijing Olympics and the Paralympics for physically handicapped people next year, has pledged to improve the living conditions of its 83 million disabled people, some 13 million of whom are intellectually challenged.

Efforts will include providing more sports facilities, vocational training, employment, health and education services, Vice Premier Hui Liangyu, an honorary president of the organising committee of the Special Olympics, said last week.