I'm not a sprinter so the following may be garbage, but what the heck.
Does anyone know of a good article that describes exactly how the measurement system operates? Pictures I've seen show a box mounted at the back of the starting block assembly but it is not apparent how it measures the start. I had assumed it was a load cell but it appeared to be behind the back mounting bracket and so out of the load path. So it could be an accelerometer but that would require rearward motion of the starting block to trigger the accelerometer. Or is it vertical? When the runner pushes off there will be both a horizontal and vertical vector. Does the vertical component result in the blocks compressing the track surface and so triggering the accelerometer?
I also wonder what effect the method of attaching the blocks to the track (bolts, pins dowels?) could have. Also whether the nature of the track surface can affect the system? A hard mount system would increase the response of a load cell system and decrease the response of an accelerometer. A soft mount would have the opposite effect deadening the load cell but increasing the reaction of an accelerometer.
It is obvious something was different at Eugene. Has anyone drawn up a list of all the variables. It could be something as simple as mounting bolts were supposed to be done up finger-tight but some one took a wrench to them and so changed the whole dynamic characteristic of the system.