Growing awareness of football-related head injuries has compelled coaches of many metro-area high school teams to change the way they do business, particularly on the practice field.

At Lakeville North, just one practice this season has been held in full pads, a sign of how many teams have scaled back hitting or contact of any kind.

At Minneapolis Washburn, seven players have missed anywhere from a few days to two weeks of practice after complaining of headaches, a byproduct of more-informed players coming forward.

And at Wayzata, a spate of shoulder injuries has coaches believing there's a link to ongoing efforts to improve blocking and tackling techniques to avoid head injuries.

One thing is clear: Macho one-on-one, king-of-the-hill showdowns, once a common occurrence in daily preparation, have been replaced by instructional drills and a line of physicality that coaches refuse to cross.

"[Practice] has changed a lot," said Lakeville North coach Brian Vossen. "We never tackle to the ground, and we always thud up. We are constantly coaching guys to stay on their feet."

Most coaches agree that the risks of tackling a player to the ground in practice far outweigh the rewards.

"Thud" is the new buzzword, meaning that players go full speed until initial contact, then back away.

"We seldom go live in practice," said Henry Sibley coach Tom Orth. "It's generally tag or thud tempo."

Fearful of losing a player to an injury that could have been prevented and mindful of today's safety-first guidelines, coaches are wary of anything that even resembles a head injury.

"It's a sin to lose a player in practice," Wayzata coach Brad Anderson said.

Teaching the proper way to tackle -- keeping the face up, not leading with the helmet, hitting with the shoulder and wrapping the arms around the ball carrier -- has been a far greater point of emphasis in recent years. Not just how to do it, but calling out instances when it's done sloppily.

"We do form and technique tackling every day of the week now," Anoka coach Jeff Buerkle said.

Wayzata sees new injuries

At Wayzata, Anderson has minimized the amount of high-speed, high-risk collisions in practice since he took over as coach in 1999.

When a practice injury does occur, Anderson said, coaches analyze how a drill might be done differently to prevent additional injuries.

So far this season, the Trojans have seen a notable increase in shoulder injuries. That has Anderson investigating a possible link to the Trojans' techniques for doing more with the shoulders, arms and hands than the head.

Trojans offensive linemen previously blocked by keeping their arms tight to their bodies and driving their facemask and hands into an opponent. Now the big fellas make more contact with their arms fully extended, leaving shoulders more vulnerable to wear and tear.

"We do believe there is a correlation with trying to keep the head out of contact," Anderson said.

The increased focus on avoiding head injuries has occurred amid a rise in player reports of problems at Wayzata.

Last season there were 37 cases of players hit in the head or having reported or showed concussions symptoms and could not continue playing on the day of the incident. That's up from 13 in 2010. There were an average of 7.2 cases per year from 1992 to 2002.

Chris Thein, a certified athletic trainer with the Institute for Athletic Medicine who works with Wayzata, said the numbers reflect greater honesty by players rather than increases in violence on the field.

'Err on the side of safety'

At Washburn, the more cautious approach to head trauma is a reflection of broader base of knowledge among players.

"When I played, you got banged up a little," said Minneapolis Washburn coach Giovan Jenkins.

"Now, when a kid gets hit, the first thing he says is that he has a concussion. And once that's out there, they can't come back until they've been cleared by a doctor. You have to err on the side of safety."

The flip side of players self-diagnosing is far riskier. While some coaches believe players might use it to miss a practice, there's also concern about others keeping potential problems to themselves.

"Some kids think they may lose their position, so they don't say anything," Jenkins said, acknowledging that some players refuse to admit their injuries. "That's a problem, too."

Coaches agree that no matter how much player safety is emphasized, playing football comes with inherent risks that will always be present.

"Football is a rough sport, and you cannot take the contact out of it," Sibley East coach Chuck Hartmann said. "But as coaches we try and limit the opportunities for injury in practice while still preparing the kids for Friday. It's a fine line.

Staff writer David La Vaque contributed to this report.