Four days after his eighth birthday last year, Cayden McCorkel's head slammed into the ground on a football field in Woodbury. "My friend tackled me super hard, and then I hit my head super hard to the ground," he said, recalling what happened as he fidgeted on his front porch.

He did not tell his coaches, but complained that night of headaches and nausea to his mother, Krissy. Though a brain scan showed no damage, a concussion was diagnosed and Cayden missed a week of school. He sat at home, bored, with strict instructions not to watch television, play video games, read or play outside.

Now as another football season begins, and as Cayden still occasionally complains of headaches, the frightening world of concussions and youth sports has again enveloped a Woodbury couple, their rising athletic son and the coaches who can already see his potential. For almost a year the family -- like others throughout the Twin Cities sports landscape -- has struggled with the doubt, fear and confusion that comes in navigating a world they still know little about but is getting bigger headlines by the day.

His mother, acknowledging the worries that "are still in the back of your head," decided to sign him up to play again this fall. She hopes that Cayden's recent need for a tutor to help with reading in school is not linked to the concussion. His father, Anthony Cannady, a landscaper, needed even more persuading.

"I didn't want him to play anymore," he said of the concussion. "Just then and there, I was done."

An avid sports fan and a former high school baseball player, Cayden's father said he winced as he watched yet another former National Football League player -- this time retired quarterback Kurt Warner -- talk about the health impacts of getting repeatedly whacked on the football field. He also wondered aloud, as Cayden and his teammates practiced on a nearby field, whether the persistent migraines that Vikings receiver Percy Harvin has had might be the result of concussions.

But the family's own ties to pro football can be seductive -- Krissy said her dad golfs with former Viking Randall McDaniel, and said her father attended McDaniels' induction ceremony at the Pro Football Hall of Fame. Cayden, she added, has a special Hall of Fame football signed by McDaniel.

So Cayden's father could be found reluctantly driving his son to football practice on an overcast late Sunday afternoon.

"If he gets another one, he's completely done," said the father.

Does his son understand that? "No, he doesn't know that," he added.

Bob Lawrence, Woodbury's coordinator for third- and fourth-grade football, said he was unaware of Cayden's concussion last year, but said no one goes back onto the field without medical clearance and his coaches have been trained on what to do if they suspect a concussion. Besides, he said, no one at Lake Middle School, where dozens of blue- and white-helmeted boys now practice almost daily, is hitting anyone nearly as hard as what you see in the NFL.

"It's kind of like comparing your 16-year-old getting his driver's license to an Indy car" driver, he said. "The guys in the NFL are so much faster, and they hit so much harder."

At football practice, Cayden is all eager energy. He's the fastest player in the team's wind sprints, and skips water breaks to line up first for the next drill.

"Right now, we're looking at tailback, and probably linebacker," said head coach Kevin Gaulke about where he might play Cayden. "He's just talented. He knows the game."

Gaulke said Cayden's mom told him about last year's concussion, and that "you keep an eye on it, for sure."

A 'success story'

But Jim Nienow, an assistant coach, said the fact that Cayden played football -- and then baseball this summer -- without another concussion was a good sign. "It's a success story, I think," he said.

In a one-on-one drill last week, Cayden lined up as a defensive player and drove his opponent back 8 yards, knocking him down. "You're all right, shake it off," a coach told the player lying on the ground.

With Cayden again leading the team as they finished their wind sprints, another coach barked to the team.

"What quarter?" he said.

"Fourth!" the players yelled back.

"Who beats us in the fourth quarter?" he asked.

"No one!" they replied.

Cayden was medically cleared to play after the concussion last fall and scored a touchdown -- sometimes two -- in almost every game. He had a 40-yard scamper to score the winning points in the final, big playoff, and his mother said she remembered "standing on the sidelines, like, screaming" for joy. Even Mike Bailey, the father of a teammate, said Cayden's talent is hard to ignore. "He had moves. He had speed," said Bailey. "He had a lot of big runs last year."

With an eye toward his own son's safety, Bailey said he spent $60 buying him a better helmet. Camille Willner, another parent watching practice in a portable canvas chair, said her son, Trenton, took a concussion base line test a year ago "just as an extra precaution."

Though he agrees it is not the NFL, Bailey said you can "hear the shoulder pads [and] helmets" pop a couple of times a game. He said he has told his son, Brandon, that "you have to explode and make the contact because it's going to hurt the same, or worse, if you don't."

Cayden -- No. 43 in a black and blue jersey -- took off his helmet after a more than 90-minute practice last week. "Really tired," he said. "I didn't [sleep well] last night."

His mother, an administrative assistant at a law firm, often watches the beginning and end of practice, toting 2-year-old daughter Ava and the family's new puppy, Lola. She said she bounces between being happy and worried, especially after reading reports that a person having one concussion is likely to have another.

For much of the summer, Cayden was tutored by a teacher after he showed signs of falling behind in reading. Absent any hard evidence that the concussion is related to his learning ability, his mother said she would continue to believe the two are not connected. "I just want him to get really good grades," she said.

But the doubts linger.

"Ever since [he] had the concussion, he complains about headaches often," Krissy said. "Not like 'often-often,' [but] more than I would think a kid would.

"I always question if it's from, like, the concussion," she added.

Still, she watched another evening practice as her son, now playing defense, took down a teammate with a hard tackle, and got a high-five and a slap on the helmet from his coach. "You need to catch up with me [in a few years] and see how Cayden's doing in sports," said Krissy, now smiling.

His father, despite his concerns, agreed that his son's talent is easy to see. As a birthday present, he plans to take Cayden to the Vikings' first home game in a few weeks. "Yeah, I've got me a little athlete," he said.

Mike Kaszuba • 651-222-1673