What was the corruptible crown that the athletes ran for?
The corruptible crown the athletes ran for was merely a wreath of leaves and similar material. By the time they returned home it had dried up and become good for nothing. It was a perishable prize, contrasted with the incorruptible crown believers pursue.
Les explains that Paul in 1 Corinthians chapter 9 is writing to Gentile believers and alludes to the Olympic athletes. Those athletes trained and trained, but with temperateness, not destroying their bodies by overtraining or coming flabby and in no condition to run. They prepared with common sense for the races. Paul says they did it to obtain a corruptible crown, which was just a wreath of leaves and so forth. By the time they got home, it was all dried up and good for nothing. In contrast, believers who are running a race for reward look for an incorruptible crown, one that will never end.
And every man that striveth for the mastery is temperate in all things. Now they do it to obtain a corruptible crown; but we an incorruptible.