Consistency is what all NFL players strive for week in, week out. It's what separates the average running backs from the elite ones.Running backs like Derrick Henry have no issues with consistency, as when he's healthy he's been one of the best backs in the NFL for the majority of his career.However, there have been more than a few occasions where a running back has had one outstanding season, before returning to be average or below for the rest of their NFL careers.NFL best one-year wonder RBs ever#5 - Ickey WoodsIckey Woods as a member of the Cincinnati BengalsAs a rookie in 1988, Ickey Woods of the Cincinnati Bengals looked like he had a bright future ahead of him.He led the league in yards per carry and had over 1,000 yards on the ground during his maiden year. Woods also added 15 touchdowns as the Bengals made it to the Super Bowl before losing to the San Francisco 49ers.However, early on during his second year in the NFL, Woods suffered a devastating ACL injury and was never the same. He had less than 500 yards for the remainder of his career, which was only three seasons as he was out of the NFL by 1991.He did leave a legacy though, as the 'Ickey Shuffle' celebration was, and still is, a happy memory for Woods and the Bengals.#4 - Spencer WareKansas City Chiefs RB Spencer Ware had one season in the spotlightSpencer Ware had his breakout season under Andy Reid with the Kansas City Chiefs back in 2016.After being used sparingly by both the Chiefs and Seahawks, Ware got his break during his second year in Kansas City and had over 1,400 scrimmage yards. He had 921 on the ground and 447 through the air, while adding five total touchdowns.However, he suffered a torn PCL in the following preseason and never looked the same. He came back to play two more years in a backup role for KC, but was out of the NFL after the 2019 season.