I've heard a few:
1)Guy on my HS track team claimed to run a 5:20. He ran a 6:30 in his only 1600m the next year.
2)6' 200lbs football player claimed to run a 4:50 in fall weight training. During track he ran like a 1:00 400m.
3)Went back to my HS to do a 3xMile Workout, afterwards a guy on the XC and track team claimed to run a 5:30 mile. When I know that he hasn't even broken 21 minutes for the 5k.
Then again, I went to the school that just started XC my junior year and was coached by the head basketball coach. After he got done driving the bus. So he wanted to start practice at 4pm..in September..in North Carolina. It's like 95 degrees here easy at the time.