Imagine climbing to the peak of 7,000-foot mountain. Then, when you reach the top imagine being forced to sprint 20-yard segments over, and over and over with only 6 minutes of rest between each bout of sprints. Oh yeah, and the whole time you are running there are cannons shooting projectiles at you from three different angles.

Welcome to a day on the San Francisco 49er defense.

Every 49er defensive player was beyond exhausted. The anemic Arizona Cardinals, a team that was able to muster one touchdown in three games, ran 83 plays Sunday night. They wore down a 49er defense that entered the game missing its best defensive player in Julian Peterson and two starting defensive backs, Ahmed Plummer and Mike Rumph.

From the middle of the third quarter until the end of the game you could just see the energy escaping each 49er defensive player with every exhale, every 49er three-and-out, and every incomplete pass. I don't know that they had enough time to walk to the bench before they had to turn around and get back on the field. Early in the fourth quarter Bryant Young fended off a double team on the left end and managed to sack McCown for a loss. Instead of celebrating or jumping up and getting ready for another play Young just lay on the ground with his hands raised in celebration, unable to do much else since the energy needed to do so might have sent him into early retirement.

Yes, the 49er defense ranks last, or next to last in almost every statistical category. But really, they are not as bad as the stats make them seem. They have an explosive front 7 than can keep opposing running backs in check. Bryant Young leads the NFL with six sacks. Six times the Arizona Cardinals were moving the ball on the 49ers and six times the defense held and made them settle for three points. It looked more like fútbol than football with the number of field goals Neil Rackers had to kick. The defense even managed to outscore the offense (Two TDs to None), and has scored at least one touchdown in the last two games. The problem, however, is that they spend more time on the field than Michael Jackson spends in court.

The defenses problem so far, is the offense. So far this season, the 49ers' offense has not had the ball for more than 30 minutes in a game all season. Meaning that for more than half the game, and in some instances, almost two thirds of the game the defense is out on the field. The offense only has 47 first downs, 10 of which were earned on the ground. In other words, the 49ers don't move the ball very well.

The 49er have completed four weeks of what is sure to be a grueling sixteen week season and already fans are getting exhausted of the pattern. Start out strong, make a couple plays, and build up hope only to crumble near the end of the game. Mike Nolan has to find a way to break the pattern. He has to find a way to get the offense on track and put together a drive longer than 9 yards, or 9 seconds; preferably both. Unless Nolan can figure out how to create some offense his defense is going to be slowly swallowed up and devoured by the eventual breakdowns that occur as a result of exhaustion.

And when it comes time to play the blame game remember first what the defense has to play through before crucifying them.