St. Joseph, Mo. ? Jamaal Charles took a shovel pass from Alex Smith, darted through a hole in front of a few thousand fans — and was promptly laid out by Chiefs linebacker Derrick Johnson.

No worries, even in a training camp practice. The Pro Bowl running back popped up after a few seconds, brushed himself off and headed back to the huddle, knowing full well that he would have a chance to deliver a little payback the next time his fellow Texas alum came on a blitz.

You see, Charles may be known for his slick moves and world-class speed, but he also relishes a chance to lay the lumber on an unsuspecting defensive back or hard-charging linebacker.

“I love contact,” Charles explained. “I don’t like getting embarrassed when a linebacker tries to bull rush me. I told my (fellow) running backs, ‘This is the Jamaal Charles rule: As long as you can hold them for three seconds, you’re good.'”

In other words, Charles promises to hold the fort for three seconds. If the quarterback fails to get rid of the ball by then, whatever happens next is on them.

He’s done a good job of it, too. Replay game films from last season, when Charles was having the most productive year of his career, and you’ll find that he was also doing his duty protecting Alex Smith. It’s for that reason Charles has become a rarity in the league, an every-down running back who remains on the field even in obvious passing downs.

“You have to have the motivation to do it,” he said. “You just have to be hungry. You just have to feel like you have to go knock their head off before they knock yours off.”

Charles said he learned the importance of blocking during his days at Texas, when people began to question his NFL potential given his relatively slight stature. If he was going to make it in the league, he would have to be able to block the biggest, burliest guys around.

Even now, when a rookie such as De’Anthony Thomas arrives in Kansas City, Charles puts his arm around his shoulder and explains, “If you can’t block, you can’t play.”

“In your mind you have to have the will to do it,” Charles said. “You’ve got to have the will to go out there and want to knock somebody out. I don’t like to get hit, so I’m going to hit you before you hit me. Whatever I have to do — I’m going to hold you, hold your jersey, hold your leg, but you’re not going to get to the quarterback.”

Well, at least for three seconds.

Charles earned his contract extension, and the roughly $18 million that was tacked onto his deal, mostly on the weight of his gaudy rushing stats. But the truth is that it’s his blue-collar nature that truly endears him to the guys in his locker room.

“He has one of the greatest work ethics around,” fullback Anthony Sherman said. “He comes in day-in, day-out. It doesn’t matter if he’s making $8 million or $1 million. He comes in and works every single day with everything he has left in him.”

That’s also why nobody really blinks when he takes a shot in practice.

Even one from Johnson that elicits a gasp.

“Listen, it’s a physical game and we’ve got to get Jamaal ready to play, and he’s got to understand that,” offensive coordinator Doug Pederson said. “He’s going to get hit.”

And you better believe he’s going to hit right back.

“If you bull rush me, I’m going to come back the next play and cut your legs. So if you’re going to bull rush me, I can play your game as well,” Charles said. “I’m not the biggest or the strongest, but I’m going to test him first so if he tries to come up to me, I’m going to try to cut him and chop his legs off so next time it’ll slow him down.”

Notes: Since returning from a hamstring injury, WR Junior Hemingway has received considerable snaps with the first-team offense. … Thomas left the crowd gasping in awe once again, shaking a couple of defenders on a lengthy touchdown run in Monday’s practice.