Clayton football coach Gary Fowler wasn't pleased when his son Drew was overlooked by area colleges as a senior in 2003. Drew eventually signed with the Air Force Academy, where he had an exceptional career and earned a berth in a postseason all-star game as a linebacker.

But it took participating in a football combine at Apex High School last month for Gary Fowler, coach of the North Carolina team for the 2008 Shrine Bowl Game of the Carolinas, to understand exactly why Drew had been passed over.

"They ... looked at his 40 time and put a line through his name," Fowler said.

That's one reason it hurt the coach a little each time he put a line through the name of one of the 900 players who participated in the three combines held to identify prospective members of the North Carolina team that will compete in the Dec. 20 Shrine Bowl of the Carolinas.

With the stroke of a pen, based on an objective measure of strength or speed, a young man's hopes of playing in the all-star game were greatly diminished.

"It bothers me," Fowler said. "I wish I knew what was inside their hearts. I wish I knew how badly they want to play."

With no hope of learning the motivation of every prospective player, Fowler and his staff will rely on information gleaned at a combine, tapes of games and recommendations to choose their team.

"On the days of the combines, I told every one of them to have a good time," Fowler said. "There was no guarantee.

"We are not giving out scholarships, but we could give them a chance of a lifetime" -- the opportunity to play in a Shrine Bowl.

Football combines -- in which high school players are put through drills, measured for height and weight, tested for speed, strength and agility, and compared with each other -- are held throughout the spring.

There are various sponsoring organizations, and the drills are conducted in various ways. But the goal, much as it is in the scouting combine for college players that leads up to the NFL draft, is to see which players stand out, at least by the numbers.

There is no easy way to measure "heart," but size, strength and speed are another matter.

Here are some of the key categories coaches use to evaluate high school players:

40-yard dash

The players were buzzing with the talk of 40-yard dash times during the Apex combine.

College recruiters, who get a full set of the combine results, may be more interested in the pro agility drill or the vertical jump than the 40, but those drills have to be explained.

The 40 is pure speed.

But the players aren't really as fast as their 40 times seem to indicate.

At the start, they take a three-point stance -- one hand on the ground -- and are told to go when they are ready. At least two coaches per runner start their clocks when the player's hand leaves the track.

Reaction time is not a factor, because there is no starter's pistol. Every player has the advantage of a rolling start -- he is moving forward and may even get in a step before his hand leaves the track.

Durham Jordan's Torrance Hunt ran a 4.22 at the Apex combine, but he prefers to use a 4.25, an electronically timed sprint at a Nike combine in Baltimore. (His time in another drill, the pro shuttle, was 3.97, but he uses a 4.37.)

Regardless, his mail has increased. Hunt said he has heard from two or three schools since his times have become available.

"I think there has been some talk about my speed," he said. "Speed is the key in football, especially at my position [cornerback]. You have to run fast to keep up with the receivers."

The Shrine combine times are fast, but they do provide a basis for comparison. Every player is timed using the same procedure.

Bench press

The bench press is an indicator of upper-body strength. Players lie on their backs and raise a bar with 185 pounds of weights as many times as they can.

Raising the bar from the chest with straight arms extended counts as one repetition.

A 300-pound lineman should be able to lift the weights at least 20 times. If he can't, not only is his strength questioned, but also his work ethic.

When Smithfield-Selma linebacker Justin Dixon (6-foot-2, 230 pounds) popped off 32 repetitions at the Apex combine, the performance was eye-opening.

"He loves to lift, and he spends a lot of time in the weight room," Smithfield-Selma coach Anthony Barbour said. "He is naturally fast and naturally strong, but he works at those things all the time."

Ty Howle, a 290-pound center at Bunn, already has committed to Penn State, but the combine gave him a chance to compete.

"I wanted to go up against the best and see how I stacked up," he said.

Howle was a little disappointed in his lifting (31 repetitions). He has done more during workouts.

Pro shuttle

The 20-yard pro shuttle may be the best indicator of the ability to play football.

A player straddles the middle of a 10-yard wide box. At a signal, he runs to one side of the box (5 yards) and touches the line, runs all the way across the box (10 yards) and touches the line, and sprints back to the middle.

The test shows speed, agility and the ability to stop and change direction.

Vertical jump

The vertical jump might seem better suited for basketball, but the ability to jump shows leg strength, which is crucial in football.

At the Shrine combine, players stood on a computerized mat and jumped as high as they could. A clock started when a player left the mat and stopped when he touched down.

The clock measured hang time -- time in the air -- and converted the time into inches.

Putting it together

The combination of physical performances at a combine provides insight into a player's abilities.

But the results sheet tells only part of a player's story.

"Getting the physical information is a lot easier than the intangibles," Fowler said.

Can a player get along with his coaches and teammates? Will he work hard? Will he be able to adjust mentally to not being a superior athlete?

Can he learn the playbook or the defensive adjustments? How does he play under pressure?

"You can't measure any of that stuff," Fowler said.

"This process has really given me more more appreciation for what the colleges go through.

"I've got about 900 [athletes] to look at and pick a team to play one game. It is a tough job."