A coworkers son was on his high school's track team. He decided to run a marathon before the track season started. His coach warned him that if he would be DONE for the season. The son ran it anyway. He did not run track for his team. My coworker said the problem was son thought he wouldn't miss-a-beat and he would immediately run and train like always. He ended up injuring himself by ignoring any post-marathon recovery.