The DVD assumes little-to-no experience with competitive swimming and starts off in the pool citing the need to build confidence in a controlled environment.
Mental toughness is skill. You need to learn how to suffer. You practice perseverance everyday when you are out training in the bad weather, when you ride or run further than you have ever gone.
My dog is an intelligent runner. She does a big stretch before she does anything. She starts out slowly and gradually builds up speed until we are running very fast.