On the worst days, when his head throbs and his body aches from too much basketball, Archbishop Spalding High School senior Justin Castleberry dreams about his upcoming vacation, about his much-needed break.

But school doesn't start until Aug. 30.

Too bad, because for Castleberry and other top-level high school basketball players, summer vacation has become the busiest time of the year. During a three-week stretch that runs until the end of July, Castleberry will play about 40 games, more than he does during the three-month high school season. Throughout the summer, he spends 10 hours a week lifting weights and 15 hours practicing, leaving no room for part-time jobs or family vacations.

Summer demands have skyrocketed across high school sports, but nowhere is a year-round commitment more essential than in men's basketball, where teams -- and scholarships -- are made during the offseason.

"There's never really any break," Castleberry said. "Basically, my whole summer is 100 percent devoted to basketball, even though it's a winter sport. I can't stay out late with friends or get a job. I just do this."

When Castleberry decided to commit to year-round basketball, he thought only of the opportunities it would unlock, not the ones it would quash. "If you want a scholarship," Spalding Coach Mike Glick told him, "then you better get it right now."

Players race from one camp to the next, from one game to the next, hoping to catch the attention of a college coach. Castleberry feels dizzy just reviewing his schedule: a week and nearly 20 games at the Eastern Invitational in New Brunswick, N.J.; a handful of workouts at Spalding in front of college coaches; weekends filled with summer league games at St. Albans.

"I don't even think about what I'm doing, to be honest with you," Castleberry said. "It's just go, go, go. This is the most important time of year."

And he's spent months preparing for it. Castleberry and teammate Lawrence Dixon started working out the day after school ended, and since then they've rarely left basketball behind.

Glick told them how to prepare: Lift weights three nights a week, practice for about an hour each day and play as many games as possible. "Ideally," Glick said, "they'll be preparing for about 25-30 hours each week. That's their summer."

What about a part-time job? "There's just no way," Castleberry said, "that I could possibly have one."

What about his family? "I'd like to go see my dad in Texas," Dixon said, "but that just doesn't fit in right now."

What about a break -- one innocent little break? "For top-notch players these days," Glick said, "there's really no chance to get one."

Coaches often blame the hectic pace on the NCAA's open evaluation period in July, which provides players with a summer showcase more important than anything during their high school season. College coaches can evaluate high schoolers during two 10-day stretches, from July 8 to 17 and July 22 to 31.

Next year the NCAA will increase the break between the periods by three days. "We want to give players a little more rest," said Steve Mallonee, managing director of NCAA Division I membership services. "We know that, for them, this is a high-activity period."

A high-stress period, too. Hundreds of college coaches flock to camps such as the Eastern Invitational so they can evaluate 300 highly regarded players at one place, instead of flying around the country to watch individual high school games.

Hungry for lucrative scholarships, athletes and parents are more than willing to accommodate them.

"Kids would play 24 hours a day if that's what they had to do," said Ned Sparks, the executive director of the Maryland Public Secondary Schools Athletic Association. "They might exhaust themselves. They might get tired of basketball. But they believe a scholarship can make it all worthwhile."

Take Castleberry and Dixon, who swear that three months of physical stress and emotional exhaustion, three months of going to bed early while friends stay out late, will be made worthwhile by a free college education.

Castleberry has been offered scholarships by several Patriot League schools, including Bucknell, Lehigh and American. Dixon is weighing offers from about six schools, including St. Francis and Holy Cross. "The offers keep you doing all the hard work," Dixon said. "We use those for motivation."

Younger, lesser players drain themselves during the summer months, too, while eyeing different incentives, like improvement and playing time.

Players at Annapolis High School and Glen Burnie High School aren't yet competing for scholarships, but they still spend their summers playing basketball. At both of those schools, players compete together in summer leagues, playing about 25 games over the summer.

"The core people on our summer team will be the core players on our team next year," said John Brady, head coach at Annapolis. "We don't say, 'If you don't play in the summer, then you won't play during the year.' But it sure hurts kids if they don't play in the summer. They'll fall behind everyone else."

"Our kids are in the gym lifting three nights a week and playing every other day," said Mike Rudd, head coach at Glen Burnie. "Obviously, that's not unique. These days, it seems like everyone lives and breathes basketball the whole year."

Even when players deviate, they do so cautiously. Dixon bucked the trend and decided to get a part-time job at a barbecue restaurant near his house. Still, he misses work often for summer league games or nighttime workouts.

"Before I took the job, I explained things to them," Dixon said. "They know my priorities. Basketball comes first, before basically everything."

Spalding's Marquis Sullivan (23) sails to the basket over St. Mary's defender Mike Schlichter during a Ban the Brick Summer League game last weekend.Spalding senior guard Justin Castleberry (5), above, tries to catch up to St. Mary's Mychal Stanford. Below, Spalding forward Johann Jones weighs his options as St. Mary's Joe Goetschius, left, and Chris Haskins play defense.