What was going on with running backs in 2003?

It seems like so many RBs had insane seasons in 2003. Most memorably Jamal Lewis rushed for 2k yards and Priest Holmes set the (since broken) rushing and scrimmage TD record, but so many other RBs were so good this year too. LT led the league in scrimmage yards with 2370 and had the best year of his career aside from his historic 2006 season. Deuce McAllister, Ahman Green, and arguably Clinton Portis and Fred Taylor all had their best seasons of their careers in 2003. Ahman Green had 2250 scrimmage yards and 20 total TDs and didn’t even make an all-pro team. Fred Taylor had his career high in rushing and scrimmage yards and didn’t even finish top 5 in either. 5 total RBs had over 2k yards from scrimmage. I don’t know what they were putting in the water over in running back town, but I want some of it.