BEIJING (AFP) - Yao Ming and many of China's other top athletes pledged "glory to the motherland" on Friday as the nation's biggest-ever Olympic team was unveiled for the Beijing Games. At a ceremony in Beijing to unveil the squad of 639 athletes, basketball star Yao, reigning 110m Olympic champion Liu Xiang and dozens of others vowed in unison to do the nation of 1.3 billion people proud. "For the glory of the motherland, I will, during the Beijing Olympics, doggedly struggle, summon all courage and energy to be first, compete with fairness and friendship, win without pride, and lose without losing spirit," they said, according to an account on the popular Web portal "We will achieve the twin goals of athletic success and civilised spirit, make a good showing for the nation's people and win honour for the motherland." They also vowed to "resolutely resist provocation". Footage on the national television news broadcast showed Yao towering above his teammates and raising a clenched fist as everyone chanted. China's Olympic team is its biggest for any Games and also outnumbers the 596 athletes being sent by the United States, its chief rival for medal-table supremacy. The number in each team is determined by a number of factors including reaching the Olympic standard in each discipline. China are hoping home advantage will help them knock the United States from the top of the table after finishing just behind them at the 2004 Games in Athens, when China sent 407 athletes. Steve Roush, chief of sport performance for the US Olympic Committee (USOC), said this week China's squad would give the United States a run for its money. "China has an incredibly strong team. Host nations generally have home-field advantage. There's a job to be done," Roush said. In Athens, the United States claimed 102 medals, 36 of them gold. Russia took 92 overall, 27 gold, while China had 63 overall with 32 gold. Despite China's high hopes, Deputy Sports Minister Cui Dalin in April played down expectations of a medals avalanche. "This is the first Olympics where our athletes are competing at home and they face a whole new competition environment and a whole series of difficulties never encountered before," he told state media. "The gap between the Chinese competitors' performances in swimming and athletics and those for foreign competitors is vast," he said. Defending hurdles champ Liu and London marathon winner Zhou Chunxiu are widely viewed as China's only realistic chances of gold in athletics or swimming. Hopes of topping the medals table are seen as hinged on sports where China is traditionally strong - table tennis, badminton, gymnastics and diving. It will also be aiming to add to the tally in lower profile disciplines such as canoeing, boxing, beach volleyball, synchronised swimming, women's weightlifting and shooting. In total, China will have a 1,099-member delegation comprising athletes, coaches - 38 of them foreign - support staff and officials.