COLUMBIA, S.C. — A top researchers on heat-related illnesses called on high schools to cut back two-a-day preseason football practices the way the NCAA forced college teams to do six years ago.

Douglas Casa co-authored a study from the National Athletic Trainers Association released earlier this year. He spoke Thursday to about 250 college and high school athletic trainers at South Carolina Athletic Trainers Association.

The NCAA adjusted its football practice guidelines in 2003 to mandate five days of single-session workouts to acclimatize to sweltering summer heat.

College "coaches were screaming about that before it happened," Casa said. "You don't hear anything about that now. They've found players are healthier, fresher and perform better during the season."

At least 29 high school players have died from heat-related illness since 1995, sometimes, Casa says, because coaches and personnel don't react quickly enough to the symptoms. "Coaches think someone didn't do the proper conditioning over the summer or that they're a wimp, that they're no good for the team," he said.

The NATA guidelines call for five days of single-session practices. Once two-a-days start, they should be followed by a single-day session. The recommendations cover the first 14 days of practice.

Casa told the crowd that he watched one TV report about last month's release — and cringed when a Texas coach said while such suggestions might be necessary in other areas, they were not needed in the Lone Star State where teams sometimes go through three-a-day sessions with just an hour break between.

"If there's one message you should take back, it's please keep the coach away from my sick child," Casa said.

Casa is consulting in the lawsuit for the mother of Max Gilpin, the 15-year-old football player in Kentucky who died last August three days after collapsing at practice. The coach, David Jason Stinson, pleaded not guilty to reckless homicide. A trial is scheduled for next month.

Casa knows too well that his biggest barrier will surely be old-school coaches, who believe two-a-days toughen a team.

"I don't buy it," Casa said. "Why can't you win a championship starting two-a-days on day six instead of day one?"