Traumatic disappointment and delayed healing

I was just on a call with an interesting elite athlete, and he's been injured. 
 
He had one particular injury in his foot and then started having a completely different injury, as soon as that injury in his foot was starting to heal.
 
We were talking about how disappointment can lead to more and more setbacks.

The phrase he used struck me. 

He said, “I think it might be traumatic disappointment.”

What is traumatic disappointment and what kind of effect can it have on delayed healing in an injured runner? 
 
Well, that's what we're talking about today on the Doc On The Run Podcast.