rugby is constant impact pretty much, the only rest they get is running at another player about to hit you or waiting in a lineout for 10 seconds getting ready to be hit again

and i dont think youre giving rugby players enough credit djwolford. theyre pretty freakin tough, even amateurs and novices.
heck, school kids would probably stand up to that guy. they probably wouldnt hit him back as hard, but they could take a hit and get back up to make ground.