Chinese athletes had been warned by the country's Sports Ministry to avoid meat because it may contain clenbuterol, banned by the International Olympic Committee as a performance-enhancing substance.  China bans clenbuterol because of the chemical's noxious long-term effects on human health.  The World Anti-Doping Agency issued a warning last year about clenbuterol-tainted meat in China. Mexico also has a serious issue with it but pork farmers in China still use it because it produces leaner meat so the choice was avoidance or take risks. 

So Chinese volleyball players had not eaten meat for weeks (they spend billions, could they not import meat?) and, according to their coach, they paid the price.  Vegetarian diets are a fine lifestyle choice, of course, so is believing in astrology, but like astrology you should pick your spots.  A world-class athlete who is deprived of the complex proteins of meat, especially if they are not used to it, has a much more difficult time physiologically.

Clenbuterol has legitimate uses, just like steroids, it helps dilate the bronchial tubes and is used as an asthma treatment. But the coach of the Chinese volleyball team used no subtlety in blaming diet for the poor performance of his team last weekend at the World Grand Prix finals tournament:

“They have showed significant decline in their strength and fitness” coach Yu Juemin said of his squad after Sunday's defeat to the US. “We are wary of meat tainted by lean-meat powder, and we didn't eat any during the game period,” Yu told the Shanghai Daily newspaper.

In England they will have access to plenty of untainted meat, so they aren't forced to go vegetarian and they should be fine.  Just avoid the blood pudding.