After qualifying for the semi-finals of the 200 meters women's individual medley, this Monday, Chinese swimmer Ye Shiwen rejected any implications that she had doped in order to produce her stunning performances to date in the London Olympic Games.

The 16 year-old caused a sensation in the Olympic pool on Saturday when she won the gold medal in the 400 meters medley and set a world record time of 4:28.43, knocking over a second off the previous record, which had been held by Australian Stephanie Rice and five seconds off her own personal best.

What made Ye's win all the more incredible is that she swam the last 50 meters of the race faster than men's 400 meters medley winner Ryan Lochte had done earlier in the evening.

When asked about that feat, Lochte said that Ye's swim had been a topic of conversation over the dinner table, but it appears some have questioned how Ye could produce such an incredible feat.

After the race, BBC presenter, Claire Balding asked the station's swimming expert in the studio, Mark Foster, himself a former swimmer: "How many questions will there be about how someone who can swim so much faster than she has ever swum before?"

Foster said he believed that Ye's feat was within the realms of possibility: 'bearing in mind she is 16 years of age, and when you are young you do some big best times...it can be done,"he explained.

However, some have seen Balding's question as implying Ye had doped in order to produce her stunning time. The question provoked a storm of comments on Twitter with some people agreeing with Balding and others saying it was wrong to accuse Ye of cheating.

Such was the controversy that on Sunday night the BBC was forced to release a statement defending the presented and saying that she had not accused Ye of doing anything wrong.

'The Chinese swimmer had just knocked five seconds off her personal best to break a world record; in her role as a presenter it is Clare's job to ask the experts (in this case Mark Foster), how she managed to do it. There was absolutely no implication of doping,"said the BBC.

Nevertheless, following her comfortable win in her heat of the 200 meters medley on Monday, Ye was asked about the question and rejected any accusations outright.

"There is no doping, the Chinese team has always had a firm anti-doping policy,"she said.

On Sunday night she had put her win and world record down to hard work and training.

"I think that we have good and scientific training: that is why we progress. I'm very lucky because from childhood we have trained in a very scientific way, so it is not difficult for me to work hard."

"I am excited. It must be because I have been training really hard recently, that is why I got such a good result,"she explained.