I recall reading some time ago a rather inspiring and interesting story about the importance of rest while training for a sport.
This specific story was about a runner in the 50s that was training very hard for a 5K or 10K Championship, probably the European Athletic Championships. Back in those days, stated the text I read, runners would train hard without interleaving some resting days. Apparently, the benefits of rest were undiscovered, so they assumed that the more your trained, the better the results would be.
However, that specific athlete had some serious health problem about a month before the race, leading him to remain at bed for a couple of weeks. Obviously, he could not train in all this period and he was very concerned about losing all his fitness for the race.
Despite this fear, the athlete decided to go and run the race, and then it became obvious that his fitness wasn't worse but way better: not even did he win the race, but he even lapped the rest of the runners (that is, they were more than 400 m after him).
I remember reading this some years ago in a book, but cannot recall more than the details I already mentioned. Some may be even wrong (maybe it was not in the 50s and maybe it was another championship). Since I somehow assumed he as Finnish, I did some research on some long-distance runners like Paavo Nurmi, but nothing arose from that.
Is this story true? Was there such situation?