Originally Posted by
milkbaby
I like the broken seat post theory. Pics may give new meaning to "assploded"...
I don't see how you can snap a seat post while riding on the trainer. Also, I don't think he was even pedaling when this happened (or if he was, he stopped immediately) - note the blood pattern on the crank an the chain.
As someone mentioned in the thread, the most likely scenario is carbon saddle rail failure followed by the sharp end of the snapped rail in the glute.