Exercise enthusiast Paul Ryan back peddled Monday on his claim of a marathon time of under three hours, attributing the mistake to over two decades of time passed and a back injury.

Ryan said in an August radio interview with Hugh Hewitt that his best marathon time was under three hours, which would mean the fit Wisconsin congressman and Republican vice presidential candidate held under seven minute miles for the 26.2 miles race--an impressive feat for even the most avid runners.

Runner's World magazine raised questions about Ryan's time last Friday, shortly after the Republican National Convention in Tampa, Florida.

Then Ryan's staff issued a statement to the magazine last Friday where he admitted mistating his time by over an hour, finishing the 1990 Grandma's Marathon in Duluth, Minnesota race in just over four hours. The GOP vice presidential candidate said his brother pointed out his mistake, in the statement published on the magazine's website on August 31.

"The race was more than 20 years ago, but my brother Tobin-who ran Boston last year-reminds me that he is the owner of the fastest marathon in the family and has never himself ran a sub-three. If I were to do any rounding, it would certainly be to four hours, not three. He gave me a good ribbing over this at dinner tonight," Ryan said in the statement, which the campaign confirms was sent to the magazine.

Ryan blamed the fudged personal record on time passed and a back injury in an interview with WTOL in Toledo on Monday.

"I literally thought that was my time. It was 22 years ago," he said in the interview. "You forget sort of these things. I hurt my back when I was in my mid twenties, so obviously my perception of races and times were off."

Health and Human Services secretary Kathleen Sebelius, who is also an active runner, jumped on the mistake Tuesday linking Ryan's exaggerated marathon time to his character.

"I must confess, I do not do an under-3 hour marathon," Sebelius joked to the Ohio delegation at the Democratic National Convention. "Anyone who starts with the notion that you have to make up your marathon time tells you all you need to know about Paul Ryan."