After two-and-a-half hours of practicing foot skills and maneuvering the ball in crossovers and fake-outs designed to outsmart the opponent, the boys were eager for more.

No problem. Six more hours of drills and scrimmage awaited them. For entertainment, there were soccer films in the evening, if they didn't fall asleep first from pure exhaustion.

For boys who harbor dreams of playing professional soccer when they grow up, Vogelsinger is heaven.

"It's amazing," said mop-headed Grant, who plays on the Aztecs select club soccer team as well as a town team in North Andover. He explained that the work can be tiring, but it is well worth it.

"By the end of the week, you're sore," he said. "I'm already sore."

The boys attended the camp last season as 11-year-olds and liked it so much they asked their parents to send them again this year.

"It really helped us to be better players, being here for the whole week," said Brendan, who also liked the newfound independence that comes with living away from home for the first time, setting one's own alarm clock and attempting to keeping the room clean.

Youth athletics have evolved from the days of pickup games to a much higher intensity, where children as young as sixth grade play one particular sport year-round in travel, school and town teams. Some of the teams require practices as many as six days a week.

In the era of athlete specialists, it is no surprise that camps like Vogelsinger are burgeoning.

Bobbie Crump-Burbank, director of summer programs at Brooks, said parents are attracted to the Vogelsinger programs by the promise of improved skills and a bigger challenge.

"They don't mince words when they say this is a pretty intense camp," she said, ticking off the busy schedule of a typical day.

School coaches recommend the extra training of sports camps, parents hope to give their child an edge, and young athletes say it certainly helps them refine their skills. No one makes any promises, but many incoming high school freshmen attend sports camps with the hope that extra training will help them win a spot on the team at August tryouts.

Nationwide, the number of sports camps more than doubled in the past two years, according to the American Camp Association. On the MySummerCamp.com alone, there are more than 3,000 sport-specific camps from traditional baseball, cheerleading and hockey to the more unique wakeboarding, yoga and fencing. Plenty of other camps are posted online and in school systems.

Traditional camps are by no means becoming extinct, but to meet the ever-changing demands of campers, directors have added ropes courses, computers and community in recent years. In New England, general camps sometimes tack on an extra week or two post-season for those who want to specialize in one sport, said spokeswoman Rebeka Branagan.

The cost to attend specialized sports camps varies.

For an in-town sports camp sponsored by local high schools, the cost is on the lower side. Hooptown Basketball at the Andover gym and field house costs $220 for five, five-hour days, for example.

But programs with a reputation for intensity, coaching or backing by celebrity players can be pricey.

The tuition at Vogelsinger, established four decades ago by former Yale University coach Hubert Vogelsinger, starts at $780 for one week on campus and runs as high as $2,650 for three weeks.

A baseball camp co-owned by Cleveland Indians coach Eric Wedge, a former Red Sox player, drew hundreds of youngsters to its first one-week session at Merrimack College in North Andover earlier this month.

On a Wednesday afternoon during the August heat wave, Mary Saladino of Boxford stood on the sidelines at Merrimack watching her son Brian, 9, baseball hat pulled down over his blond hair, practice his batting stance. Brian's twin brother Louis was fielding in a scrimmage two fields away.

"I shelled out $900 for this, which is a lot for me," said Saladino, explaining that she was widowed 18 months ago. Nonetheless, she was delighted with her decision to send her sons to Wedge's camp. They were so thrilled with the experience that they are saving their money to pay their own $450 tuition next year.

Brian's friends Michael Rotondo, 9, of Beverly and Trevor Abraham, 8, of Boxford, were also happy with the coaching at the camp. If you asked, the best moment was meeting Sox player Coco Crisp, followed close behind by the visit from Sox manager Terry Francona and Indians All-Star Grady Sizemore.

Single mom Michelle Logomasini of North Andover gets teary-eyed when she explained that her son Matthew Lisio, 9, a baseball fanatic, was given tuition to the camp as a gift.

"He comes home and sleeps with his baseball," said Logomasini. "This is something I never would have been able to give my son myself."

Brendan Varney's father Bill looks at the experience a little differently than many parents. He does not think his kid will become a professional-level soccer player in one week. But he is certain that giving Brendan and his older son Darryl, 14, the chance to test their own drive and independence worthwhile.

"I really like the idea that they're 12 and 14, and they don't have mommy and daddy to tell them when to brush their teeth. It's a little bit of a controlled college experience," said Varney, who is vice president of the North Andover Soccer Association. "I know some of the other parents look at camps as a way to get an edge on their neighbors or whatever. My take away is a little bit different. Soccer is a little less important to me. I don't expect my kids to be playing pro soccer any time soon. But my kids are becoming independent because we kept them there overnight and they are meeting kids from all over the world."

Beside that, he can afford it.

"This is not a camp, quite frankly, that underprivileged kids can afford to go to," Varney said.

He likes to tell the parents on his teams that the best athletes, in his opinion, are the ones with a God-given talent who have the drive to make it work. His best example is the pro basketball players who started off under the lights at the inner city courts, playing ball every night for four and five hours.

Sports camp by the numbers

* The number of camps with a sports focus more than doubled in the last two years.

* Of the 12,000 day and overnight camps in the United States, 3,000 are sports specialty camps.

* 11 million children and adults attend camp each year.

Sources: American Camp Association, MySummerCamps.com

How much does it cost?

Sports camps range in price, depending on level of coaching, accommodations, intensity of programs offered.

* Overnight sports camps cost $200 to $400 per week on average.

* Day camps cost $75 to $300 per week on average.