WATERLOO - As the East High School football team screamed into Memorial Stadium, the Trojan cheerleaders led a similar assault down the side of the field.

Co-captain Lexxi Forness sprinted ahead of the rest of the squad, performing a dozen back flips while her teammates pumped their poms.

When the 13 spirit leaders reached their positions at the 50-yard line, the home fans applauded both the efforts of the linebackers and the sideline squad.

"Cheerleading isn't just cute little girls in skirts anymore," said Brandy Mefferd, who coaches the East High squad. "In the last 10 to 15 years, it's become much more of a sport. As gymnastics have been taken out of the schools, a lot more of those girls have ended up here."

Today's high school and college cheerleaders master increasingly difficult routines. Halftime entertainment now typically includes stunts, such as a human pyramid, and acrobatic exercises, like Forness' lightning-quick back flips. But the increased athleticism of the activity comes with a trade-off. A recent national study shows that cheerleading accidents account for the majority of female athlete injuries at the high school and collegiate level.

"Cheerleading is now a very aggressive, a very athletic and an almost gymnastic sport," said Dr. Richard Naylor, with Covenant Clinic's Department of Orthopedics. "And through that evolution have come more injuries."

Over the past 25 years, cheerleading caused two-thirds of injuries recorded by high school and college female athletes, according to the National Center for Catastrophic Sports Injury Research. The organization, based at the University of North Carolina at Chapel Hill, also found that the sport accounted for 67 of the 103 fatal, disabling or serious injuries recorded among female high school athletes, and 26 of 39 catastrophic accidents among female college athletes.

Report author Frederick O. Mueller blames the high injury rate on a lack of proper training. Local orthopedic doctor Naylor, who has treated cheerleader ankle, wrist and knee injuries, agrees.

"I don't think they're getting some of the trainer support, nor do I think their coaching staff is getting some of the medical or emergency training that they may need," Naylor said. "In some cases, it's still not recognized as a sport, so they don't get the gym space they need to practice, or have the proper mats and other equipment."

But several local squads have made changes to their programs to increase safety.

At the University of Northern Iowa, nationally certified coaches supervise all cheerleading practices and competitions, and limits are placed on when and where certain stunts can be performed. Those policies, guided by the American Association of Cheerleading Coaches and Administrators, were adopted after a Southern Illinois University cheerleader plunged 15 feet during a 2006 football game, sustaining a concussion and cracking a vertebrae in her neck.

"The rules were going to change, but that (accident) happened on national TV, and it accelerated things," said Nate Clayberg, UNI's spirit squad adviser. "A lot of the injuries are just natural wear and tear on the body, but most teams are now more aware of what they need to do to prevent the more serious head injuries and things like that."

East High cheerleading coach Mefferd says keeping her girls safe is her No. 1 job. The squad leader follows guidelines developed by the Iowa Cheerleading Coaches' Association, and keeps a close eye on all team routines.

In the summer, Mefferd prepares running workouts for her team, noting that staying in shape is key to preventing injuries.

"I really try to make sure that they are safe and that they are ready to move on before we do anything new," she said. "We go slowly with the stunts."

When the team performs in inclement weather, like the rain that plagued a recent game, Mefferd cuts stunts from the squad's routines. Her athletes were disappointed, but understood why the move was important. Completing a basket toss or forming a pyramid in damp conditions makes it more likely that a team member could slip and fall.

"We're a pretty safe team," said co-captain Forness. "We know how important it is."

Contact Mary Stegmeir at (319) 291-1482 or mary.stegmeir@wcfcourier.com.