Roman legions completed more than one-and-a-half marathons a day carrying more than half their body weight in equipment.
Athens employed 30,000 rowers who could all exceed the achievements of modern oarsmen.
Australian aboriginals threw a hardwood spear 110 meters or more (the current world javelin record is 98.48).And much more.
So Dirk Benedict's lament for the pansification of the American Male. as evidenced by the Battlestar Gallactica remake with his manly Starbuck being replaced by... well, a manly Starbuck, is perhaps just another step down a ladder we have been descending for a millenium.
UPDATE: Paul Kedrosky says liar, liar, pant's on fire:
While it's possible that ancient oarsmen were super-rowers, isn't it at least as plausible that our data about ancient feats is suspect? If history is written by the victors, sports history is written by the over-testostoroned victors.