For all of those who do not know me, I have been a consistent reader of BCC for over a year.  I'm 17 and go to high school in Jacksonville, FL.  I hardly comment, but I've made it my mission now to be a more active member. 

   I am a big fan of statistics.  Though there are many intangibles that factor into the game, such as 'want-to' and desire, I have figured that the most telling characteristics of an effective NFL rushing attack its the experience of the offensive line and the age of the running back.  See more after the jump.

   I did two statistical analyses on how to measure effectiveness of an NFL rushing game.  I would generally consider an effective running game to average around 100 to 120 rushing yards per game or better.  I did the tests using data from last year, and as to make the test more accurate to solely running backs, I omitted any rushing yards that quarterbacks gained (sorry, David Garrard). My reasoning for excluding quarterbacks was because quarterbacks are, on average, older than running backs, and therefore offset data.  Also, the data was taken from the 2009 season.

   I believe that younger running backs have more productive seasons on average than older ones do, but this statistic can be overturned when a good offensive line is available (see: Tomlinson with inexperienced line last year and producing with experienced Jets line).

Here is the data table I created so that you can see all of the information.

The first test compared the total combined games of experience of each NFL offensive line with the average rushing yards per game. A few interesting stats popped out at me-

1) The Cowboys had the most experienced line.  However, they had 578 combined starts, which actually is concerning and explains why their offensive line blew up this season.  Since their line was so old, they could not hold much longer. There was a clear correlation between combined starts and rushing productivity - they averaged about 122 yards per game on the ground.

2) The Jets, who have also experienced similar offensive line struggles this year, (but not to the degree of the Cowboys') had 560 combined starts.  Clearly, there is a correlation between age of offensive line and the likelihood of breaking down, as they did this season.  They led the NFL in rush yards per game at about 155.

3) Sometimes, stats do not tell the whole story.  The Colts had an ideal combined starts number (386) - but they were primarily excellent in pass blocking (not run blocking).  The Colts were last in the NFL with about 75 rush yards per game.  And here is an example of why quarterbacks do make a difference in the run game - without Garrard, the Jaguars averaged about 100 yards per game on the ground, but with him?  125 yards per game.  The same goes for the Packers and Aaron Rodgers.

   Basically, what I found from that test was that offensive line experience plays a huge factor in determining effectiveness of running the ball.  There are enough anomalies, such an injury and 'off-seasons' to denounce stats, but they are extremely useful when looking at the big picture.

The next test compared the average age of running backs on each team with the average rushing yards per game.  Here were some interesting qualities of this experiment:

1) Just because the running backs are young on a team does not mean that they will be extremely successful. While I predicted that age would play a larger factor, I was mostly wrong.  The Cardinals had the youngest average age of running backs (once again, excluding quarterbacks and running backs who did not manage to rush for 100 yards).  However, the Cardinals also had one of the lowest rushing averages per game.  Though Beanie Wells had a good rookie season, he was young and still learning the ropes of the NFL.  Yes, he was young - but some experience is needed to truly excel.

2) So what young running backs with NFL experience broke out? Chris Johnson.  The Titans had what I considered to be the perfect average age at 24.  In his sophomore season, CJ dominated because of his skill, experience, and youth.  He also had a dominant offensive line. Arian Foster is a great example of what Chris Johnson was doing last year, except not to the same degree.

3) Teams with old running backs still performed well. The top three oldest ages on average belonged to the Patriots , the Dolphins, and the Jets.  None of these teams had a designated number one running back, but they still performed due to a decent offensive line and experience of running backs.  Signs of age were clear, however, as Ronnie Brown and Fred Taylor both went down.

I hoped you liked this analysis.  If there's enough interest I will do more.