The hidden key to Super Bowl XLV

Troy Polamalu doesn't appear to be 100 percent for the Steelers. How effective will he be on Sunday? Charles LeClaire/US Presswire

Despite the millions of words spilled on Super Bowl previews every year, there is always some aspect of the actual game that ends up playing a much bigger role in the outcome than anyone expected. Any game can have dramatic, unforeseen swings; for example, nobody is suggesting that pundits should have foreseen James Harrison's 100-yard interception return for a touchdown in Super Bowl XLIII.

We're talking about subtle, steady factors that can turn the tide of a game, such as the brilliant work done by Ravens punter Kyle Richardson and the Baltimore Ravens' special teams units in Super Bowl XXV to pin the New York Giants deep in their own territory on drive after drive. During the regular season that year, the average Giants possession started with 67.8 yards to go for a touchdown, the seventh-easiest rate in football. During that Super Bowl, the Giants needed an average of 76.8 yards for a touchdown, which would have been the worst field position in the league in the regular season by more than five yards.

Of course, figuring out the unlikely game-changing factor in Super Bowl XLV before the game would sure make all of us look smarter at our Super Bowl parties. To try to figure out what factor might swing Super Bowl XLV, we've gone through and found that hidden and/or underestimated attribute in each of the last four Super Bowls.

Super Bowl XLIV: Indianapolis Colts-New Orleans Saints

Sean Payton's aggressive play calling