Paul Ryan seems to have something of a problem when it comes to telling the truth - his marathon "time" is an example. There was no reason to lie, but he did anyway.
The difference between an under 3 hour and a something over four hour time is enormous. To qualify in the NY Marathon you need a sub 3 hour time if you are male in the age range he mentions. A four hour tine is required for a male to qualify at age 70... Perhaps that's why he lied.