A couple of weeks ago, Steven Jackson figured he made helmet-to-helmet contact on a dozen of his 28 carries against the Cardinals. Sometimes it was a matter of defenders taking a certain angle, sometimes it was the St. Louis Rams' bruiser lowering the boom for that extra yard.
Just another typical, head-jarring day for a punishing 235-pound back closing in on his sixth consecutive 1,000-yard season. Giving it, taking it, playing hard but clean.
"I feel like there's very few guys that intentionally try to tackle with their head and to knock guys out," said Jackson, now in his seventh season. "The times I have had concussions, I've just taken it as a part of the game and that guys are just playing fast."
Even as NFL data shows that the number of reported concussions has increased more than 20 percent from 2009, and more than 30 percent from 2008, the guys who grind out the tough yards — and some of those who tackle them — say knocking heads is inevitable. Their overriding sentiment: let's just play.
"It's not a tickling contest," Rams defensive end James Hall said. "I'm not looking for any protection."
There's nothing stopping Jackson, Michael Turner or Arian Foster from ramming forward, full speed ahead for the first-down marker. Jackson gave Cardinals linebacker Harold Hayes a good, incidental conking on a no-gain carry to start the second half back on Dec. 5.
Arizona safety Adrian Wilson clocked Jackson a couple of times with helmet-on-helmet contact, and Hayes got in a lick when he pushed Jackson out of bounds on another play.
Nobody was jumping up and down, tapping their helmet and begging for a call. Just football.
"I hope they don't start fining the running backs for leading with their helmets because the linebackers and tackles definitely are not defenseless players," Falcons fullback Ovie Mughelli said. "If they can't get out of the way, that sounds like a personal problem for them."
Back in Pop Warner ball, running backs are taught to stay low. It gives tacklers a smaller target, and it's safer for the runner. So guess which part of the body is out front?
"I know people don't want us to run through the hole straight up and get our chests blown off," Broncos running back Correll Buckhalter said. "It's just a natural thing for the running back to run with his head down."
Vikings running back Adrian Peterson never worries about getting penalized for lowering his head. The defender who lowers his head in response will, he believes, attract all the attention.
"Actually, I've had a couple of collisions where I thought, 'Hey, well, maybe that guy's going to get fined because I know that was a helmet-to-helmet hit,'" Peterson said. "But there was no fine issued and it was no big deal to me. It is what it is."
Broncos rookie running back Knowshon Moreno said the only way through some holes is to "submarine through," though he believes that makes him more vulnerable.
"If the running back has his head down, all sorts of things can happen," he said.
It is difficult, if not impossible, for a defensive player to be ruled defenseless.
So, advantage offense.
"You get a lot of running backs trying to ram into you, Earl Campbell-esque," Broncos linebacker Mario Haggan said. "The last thing you want to do is hit a guy who's 250 pounds like Steven Jackson and think about the way you're going to hit him."
Earlier this season, Packers linebacker Nick Barnett complained he's faced too many backs with their heads straight down "trying to truck you." Cowboys linebacker DeMarcus Ware said there's a double standard, adding, "If they are leading with their head and you hit them, they're not going to call it."
Broncos outside linebacker Jason Hunter isn't alone in questioning some of the fines handed out for helmet-to-helmet hits.
"I understand the league wants to try and protect its players, and do everything they can to make sure everybody's playing safe and fair," Hunter said. "But at the same time it's a violent game, and sometimes when you're going in there at 100 mph you're not focused on how you're going to hit the guy, you're just going to make the hit."
Added Falcons linebacker Erik Coleman: "You don't have air brakes. You can't stop when you've left your feet."
Ron Bartell, the Rams' top coverage cornerback, missed Sunday's loss at New Orleans with a stinger to his neck and left shoulder suffered in a game a week earlier.
"It's one of those things, if you take a hit the wrong way or tackle somebody the wrong way it's something that just may happen," Bartell said. He said bluntly that the NFL is guilty of "overlegistating."
"It's easy for them to sit back and make judgments when they're never played the game, especially nowadays and guys are so big and so fast," Bartell said. "I understand about protecting players but it's a little bit overboard."
AP Sports Writers Arnie Stapleton, Dave Campbell, Charles Odum and Jaime Aron, and AP freelance writer Todd McMahon contributed to this report.