Looks like she freaked and pushed off with both arms. Left arm gets under her first and then the breasts make contact just before the helmet. Only wearing a tank top makes me cringe for the road rash factor.
I hope she is OK.
Just when you think people can't get anymore dumb here comes another example - please send her a get well soon card and in there write "please do not reproduce, you or your "speed bike" riding boyfriend, as the gene pool is already f'd up enough"