NEW ORLEANS – Dave and Ginger Smith were admiring the newly fallen snow – about 12 inches worth – outside their home in Holts Summit, Mo., one morning when a figure darted past the window.

The person wasn't wearing a jacket, a hat or gloves. He wasn't even wearing a shirt - just a pair of running shorts and sneakers. It was their son, Justin, who was then a high school sophomore.

While a bare-chested teenager dashing through January snow may have been an odd sight at neighbors' houses – Honey, come to the window! You have to see this! – in the Smith household, it hardly caused a stir.

"That's what he did," said his father, Dave. "He might go down in the basement and do push-ups or sit-ups. No one told him to do it, and he never beat his chest about it. It wasn't a nervous habit. It's just what he did."

Smith has yet to slow down.

Two days after last year's NFC Championship Game, general manager Trent Baalke stopped by the team facility. The only person in the team's weight room was his then-32-year-old All-Pro defensive end, who already was soaking with sweat.

"I looked at him and said, 'What are you doing here?' " Baalke recalled. "He said, 'It's either being here or baby-sitting at home, so I'm here.' "

That's what has Smith's family members curious – perhaps even anxious – about the next few months. Smith never has taken time off from his hard-charging routine because, until Dec. 16, he had never been hurt.

On that day, he was startled by a "pop" in his left arm. The push and pull of 12 seasons of NFL trench warfare finally had taken its toll on the 49ers' ironman, and Smith's triceps tendon was partially torn.

Smith insisted the arm has improved every week since the injury, and he said he's relieved knowing he can play with more abandon in Sunday's Super Bowl.

"I know how many games I have left now – four more quarters," said Smith, who was given the 49ers' highest honor, the Len Eshmont Award as the team's most inspirational and courageous player, this season.

Smith has said he will have surgery after the season, at which point he will begin a recovery of up to six months.

Said Dave Smith of the inactivity that lies ahead: "That's going to tear him apart."

Justin grew up on a 1,400-acre cattle ranch in Fulton, Mo. At its height, the ranch had 300 head.

Days began at 5:30 a.m. The family fed, watered and tended the cows, helped deliver calves, ran off predators and mended fences.

It was a steady pace of work, which Justin joined as soon as he could walk.

While most 2-year-olds sleep in cozy nurseries surrounded by stuffed animals, Smith took his naps on an idle tractor or in the cab of a pickup with real, 1,500-pound animals in the fields around him. When he woke up, it was back to the ranch.

Dave Smith said he remembered the adults watching Justin – he must have been 4 at the time – struggling to lift a bucket of grain onto the tailgate of a pickup truck. As he raised the bucket, the lip caught on the edge of the truck, and the grain spilled onto his head.

"He just turned around and got another bucket of grain and put it up there," Dave said.

Twelve years later, Smith's feats of strength were more awesome than adorable.

Ted LePage ran the weight room at Jefferson City High School at the time and said Smith was part of a close-knit group of boys who spent hours amid the bang and clatter there and who pushed each other months after the football season ended.

"If somebody did a certain weight, (Smith) was going to lift that much more," said LePage, now the school's head football coach. "He'd put another five-pound weight on just to show them he could. No matter what went on, he was going to be the strongest guy in the weight room."

And Smith was.

LePage, however, said the interaction among the boys wasn't adversarial.

Smith fostered a competitive camaraderie that propelled his team to a state championship in 1997.

"There were guys in that class that weren't afraid to challenge Justin, and he loved it," LePage said. "It meant he was one of the guys."

A similar dynamic has been occurring in Santa Clara.

As Baalke will note, the 49ers' path to the Super Bowl didn't begin Sept. 9 against Green Bay. It started last January when Smith rolled into the team parking lot days after the championship game loss to the Giants and a group of fellow defenders showed up to meet him there.

"We really work hard. We lift a lot," said one member of that group, outside linebacker Aldon Smith. "We take good care of ourselves. … We're not just a team that's good in the first half; we play four quarters of good football."

When Justin Smith was 10, his family had to leave the cattle ranch, and they moved to Holts Summit, near the state capital of Jefferson City.

Smith, who signed a $45 million contract in 2008, has made enough money to be quite comfortable – and very sedentary – for the rest of his life.

Hard work, however, is ingrained in him.

And he says he wants his own cattle ranch in Missouri when he's done with football. After all, he said, his kids should know what it's like.

"Yeah, I want to make them as miserable as I was," he said, grinning. "I want them to go to college and not want to come back."

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