I think from the crashes. On the positive note, like Armstrong, you gain from experience and be able to handle similar situations in future. so the accidents, they indirectly serves as a form of confidence builder.
On the other hand, Others may take a longer to rebuild or in fact never rebuild to the original level of confidence as fear and emotions of past experiences strikes in. These group will take more challenge to work with.
So, as a sports coach in general, accidents/failures do affect athletes, for better or worse. I think as a coach, I have to be aware of this and learn about the tell tale signs so that I can help my charges.