Tennessee Titans running back Chris Johnson won't say who won his race against the cheetah.

"I can't tell you" he said. "You'll have to watch in November when it's on TV."

"I bet you didn't beat the cheetah" I said.

"How much you want to bet?" he said. "You might win some money you might not."

That race was for fun took place at Busch Gardens in Tampa this summer and Johnson has had some big laughs about it. But there's another race that Johnson isn't laughing about one he insists he's not losing -- the race against time a much more important race.

The clock for NFL running backs moves faster than your watch does when you're racing to catch a flight. Twenty-seven is young by almost all job standards and even most football positions but it's considered somewhat old by running-back standards.

Chris Johnson is 27 now. He's in his sixth season. Thirty is approaching fast.

Just don't try and tell him he's at that running back crossroads where the body starts to slow the speed isn't what it was and the explosion is gone.

"It's baffling to me when somebody can sit here and say I lost a step" Johnson said. "They don't know what they are talking about."

The numbers might lead one to say that. Johnson ran for 2006 yards in 2009 his second season in the league but in the three years since his best total has been 1364 yards. Last season he rushed for 1243 yards putting him far away from the spotlight that shined on Adrian Peterson and his 2000-yard season.

A closer look at Johnson's season shows the reasons why his numbers were down. It starts with carries. He isn't getting as many. After getting 358 in 2009 he had 276 in 2012. Peterson had 348 carries. In the first three games last season Johnson ran for 45 yards but averaged just 11 carries a game.