This was close. I guess anyone making this call would have to have a pretty high certification with the IAAF.
The only thing I can discern 100% from the videos is that Burka was never out of the lead until she went down.
It seemed to me that all of the distances races were extremely physical. The competition is getting denser at the top and we will prob. continue to see more races like this.
Looking at the 800 meter races it seems that they should go to lanes for the first 400m, or start on the track in such a way as to make the race a 3 curve event instead of 4.
I would prefer seeing a lot less contact but rule enforcement and the dynamic nature of running on the track is so complex I don't really see an obvious solution.