Ex-champs, namely Erdei MADAR Zsolt, Darius TIGER Michalczewski and Istvan KOKO Istvan ran on the Budapest marathon and needed only 3h30min for the 42km distance. I think it is pretty amazing, especially for the out of shaped version of Der Tiger. This content is protected http://translate.google.com/translate?hl=sl&sl=hu&tl=en&u=http://profiboksz.hu/2010/09/29/erdei/
I'm pretty sure he got in shape if he ran a marathon in 3 and 1/2 hours. You can't do that unless you've trained for it.
*In before posts about Dirrell, Mayweather ETC* (Yes, I know they've never won a WBO but this is the General, afterall)