Sickle-cell trait is a genetic flaw that affects the protein in red blood cells that carries oxygen to the body's tissue and organs. The trait can go from dormant and harmless to active and potentially fatal under extreme stress such as intense workouts, heat and dehydration.
"You hope it never gets to that point by taking all the right precautions, but we definitely can work quickly to get the athlete hydrated, cool them off and get them to a hospital quickly if they have a problem," Thomas said. "As long as everyone from the athlete to the coaches and medical professionals working with the athlete recognize the potential problems the trait can cause, there's no reason those athletes shouldn't be able to compete safely at the highest levels."
Plancher died when his organs failed from exertional sickling after a March 18 offseason workout supervised by Coach George O'Leary and his staff, according to the Orange County medical examiner's autopsy report. An attorney representing Plancher's parents informed UCF Friday they intend to file a wrongful death claim against the university.
Florida State Coach Bobby Bowden lost a player under similar circumstances.
FSU freshman Devaughn Darling had the sickle-cell trait. He suffered a sickling episode in 2001 during strenuous offseason conditioning and died.
"It makes you try to be a whole lot more careful," Bowden said. "I don't know what's going on inside your body. I don't know how good your heart is. We examine them as thoroughly as we can. There still can be a valve we didn't catch. It scares you to death that these guys might die. It's kind of like Russian roulette."
While college coaches are learning to watch players with sickle-cell trait -- which can be determined through a blood test -- they admit it's difficult to recognize the symptoms of a severe problem.
A sickling episode that could be fatal can be mistaken for an out-of-shape player struggling to get through drills.
"A lot of these things happen without any notice at all," Jacksonville Coach Kerwin Bell said. "It's hard. I know Coach O'Leary went through a lot of things. It's almost like asking somebody, 'Why did you allow somebody to have a heart attack in front of you?' "
Bell is quick to defer to athletic trainers, who he said have his authority to interrupt a workout if they are concerned about a player.
"The trainers know more than I do," he said. "If anything happens, they are in direct care. I don't want it on my plate."
Thomas, the National Athletic Trainers Association (NATA) and the NCAA all recommend a more hands-on approach.
The athletes with the trait should not do extreme conditioning such as mat drills and gradually increase the stress of their workouts. Warning signs for a sickling collapse include muscle pain, abnormal weakness, undue fatigue and shortness of breath. If an athlete who shows these symptoms rests and is quickly given fluids, the sickling red blood cells often return to normal.
While sickle-cell trait has caused some deaths and severe health problems for athletes, Thomas said the medical community has a much better understanding of how to deal with the trait.
"You hate to call sickle-cell trait a bump in the road," he said, "but athletes with the trait should be able to do anything they want to do."
Sentinel staff writer Jeremy Fowler contributed to this report. Iliana Lim�n can be reached at firstname.lastname@example.org.