That Chinese girl was amazing, she came out of nowhere and took a huge lead in only 100m. Great stuff!
Personally, as I have been competing in times past and currently teach and coach swimming, I wasn't too surprised that the Chinese girl surged ahead at the 400 IM event.
400 IM events is always a tricky event to compete well in, even to win in against good swimmers. Its all down to how 8 swimmers swim each different strokes at the pace that they have decided before the race and how they feel on the day.
The Chinese girl strongest stroke seems to be freestyle at that point, however I suspect it was the strokes before it that lead up to her eventually taking the No.1 spot as she may have conserved her energy for the final 100 metres sprint to win the race. For a 16 year old to do that time in the Olympics.... Stunning! But she didn't come from nowhere as she was still in the top 3 swimmers during that race before the final 100 metres.
You do have to remember that when it comes to the last 100 metres or the last 50 metres freestyle of the 400 IM, swimmers often either tense up a lot and waste a lot of energy or just relax and swim out of their skin. She just lucked out at that time and managed to relax and swim out of her skin.
It was awesome to see that at the time.
Really sad about Hannah Miley coming 5th, however I suspect she still swam extremely well for her ability and when it comes to such a difficult event as that, you have to take what you can.