[Redrum]

Maybe it is something to do w/ the different levels of conditioning, but I doubt it.

Defense is inherently more physically demanding, mostly because everyone is responsible for stopping the play no matter where it goes and how long it takes.  That means getting off blocks and continuing to pursue.  An OL can make his block and then, generally, his work is done.  Defensive players have to stay in motion, moving to the ball until the play is done.  That's very simplified but catches the essence of it.  Of course lots of offensive guys move downfield to assist the play,  but more often they don't because their job was, for example,  to take the blitzing linebacker.  Make contact, keep them out of the play and then, most often the play is over.

Also, when announcers and coaches talk about conditioning and fatigue affecting a game,  they're mostly talking about the line of scrimmage, linemen and linebackers,  who usually have contact and maximum effort on every play.  When fatigue starts to slow them down, decently called and executed plays seem to yield more yards and more breakaways.  Last night the game tilted in the second half when LSU began consistently winning the battles at the LOS.  Alabama rallied for the last drive but it also helped that LSU started coming at McCarron w/ fewer guys.

This asymmetry of effort expended is not fair,  but it wasn't fair when I played DL in high school and it hasn't changed much since.  At least, back then,  I was so slow to begin with that nobody seemed to notice when I got gassed.

* Oh, just thought of another Oregon specific one:  Their linemen are generally lighter and faster than a lot of schools'  O lines which feature 300lb + guys who are always welcome to carry more weight if it doesn't affect their blocking success.  At Oregon they recruit speed and mobility, even in their linemen, even if they are lighter.  If you look on their roster, it's the DL that are the behemoths,  more guys > 300 lbs.

[Redrum]

Maybe it is something to do w/ the different levels of conditioning, but I doubt it.

Defense is inherently more physically demanding, mostly because everyone is responsible for stopping the play no matter where it goes and how long it takes.  That means getting off blocks and continuing to pursue.  An OL can make his block and then, generally, his work is done.  Defensive players have to stay in motion, moving to the ball until the play is done.  That's very simplified but catches the essence of it.  Of course lots of offensive guys move downfield to assist the play,  but more often they don't because their job was, for example,  to take the blitzing linebacker.  Make contact, keep them out of the play and then, most often the play is over.

Also, when announcers and coaches talk about conditioning and fatigue affecting a game,  they're mostly talking about the line of scrimmage, linemen and linebackers,  who usually have contact and maximum effort on every play.  When fatigue starts to slow them down, decently called and executed plays seem to yield more yards and more breakaways.  Last night the game tilted in the second half when LSU began consistently winning the battles at the LOS.  Alabama rallied for the last drive but it also helped that LSU started coming at McCarron w/ fewer guys.

This asymmetry of effort expended is not fair,  but it wasn't fair when I played DL in high school and it hasn't changed much since.  At least, back then,  I was so slow to begin with that nobody seemed to notice when I got gassed.

* Oh, just thought of another Oregon specific one:  Their linemen are generally lighter and faster than a lot of schools'  O lines which feature 300lb + guys who are always welcome to carry more weight if it doesn't affect their blocking success.  At Oregon they recruit speed and mobility, even in their linemen, even if they are lighter.  If you look on their roster, it's the DL that are the behemoths,  more guys > 300 lbs.