Dr. Barry J. Maron, a cardiologist with more than 40 years of experience, testified it is his opinion former UCF football player Ereck Plancher died from sickle cell trait complications.

The Ereck Plancher trial continued to be slowed down by contentious attorneys, who often interrupted the proceedings with objections. Maron and UCF Athletic Director Keith Tribble were the only two witnesses who testified Thursday. Tribble explained to the jury how the UCF Athletics Association operates and the ideal protocol for handling issues related to sickle cell trait.

Maron, an expert witness hired by the Plancher family to testify during the wrongful death trial, told the jury he agreed with Orange County medical examiner Joshua Stephany's findings that Plancher's death was related to sickle cell trait.

Maron, who has been internationally lauded for his work studying the causes of sudden death in athletes, rejected the UCF Athletics Association argument a heart condition that could not be detected caused Plancher's death.

UCFAA attorney Dan Shapiro said in his opening statement Plancher's death was caused by fibromuscular dysplasia, a thickening of the heart muscle that blocked at least 90 percent of the blood flow to Plancher's heart. As a result, he said it was no one's fault the 19-year-old UCF football player collapsed and died after an offseason conditioning workout supervised by coach George O'Leary and his staff.

Maron said there was no scientific basis to refer to the thickening of Plancher's heart muscle as a disease. He said it could be a natural muscle hardening that occurs after a person dies.

When he was asked whether he was aware the medical examiner did not review slides of Plancher's cardiac induction system, Maron responded it would take a year to properly examine the heart and it is rarely done by medical examiners.

Shapiro repeatedly asked Maron if it was possible Plancher suffered from a thickened heart muscle before his death.

With no tests available to completely rule out fibromuscular dysplasia before death, Maron stressed it was possible but, in his, opinion it was not probable. "Anything's possible," Maron said.

The doctor added he thought it was unlikely a heart condition caused Plancher's death because his symptoms didn't match other athletes whose deaths were caused by heart problems.

"The death event is not only sudden, it's virtually instantaneous or within a few seconds because it's due to an arrhythmia," he said. "… [It] ends life right then. That's how it works."

The doctor said based on his review of the medical examiner's report, the autopsy report and a variety of other documents, Plancher did not immediately die after he first showed signs of distress. Shapiro asked Maron to provide more details about Plancher's final workout to support his comment that Plancher was involved in vigorous exercise, but Maron said he was only prepared to provide limited background information about the workout and didn't study the chain of events closely before testifying.

Tribble was sworn in shortly after 9 a.m. Thursday. He was questioned by Plancher family attorney Steve Yerrid.

Tribble confirmed he is an employee of the UCF Athletics Association and not a state employee. He was shown a copy of his contract, confirmed it looked like his contract and it was entered into the court record.

He played football with one of the Plancher family attorney's siblings and was Yerrid's father was one of his football coaches. Tribble and Yerrid told the jury those previous relationships would have no impact on his testimony.

Tribble told Yerrid he is African American and is familiar with sickle cell trait. He later said he could not say whether sickle cell trait causes athletes death. Yerrid then began asking about the UCF Athletics Association's policies and procedures, noting O'Leary supervises the football program.

Yerrid asked Tribble to speak about O'Leary's coaching background, asking Tribble whether O'Leary was head coach at Notre Dame for five days. Tribble responded, "I'm not sure the length of time." The judge previously Yerrid couldn't tell the jury O'Leary resigned from Notre Dame because he lied about his education and athletic background. As a result, Yerrid and Tribble never disclosed to the jury the circumstances surrounding O'Leary's brief stint at Notre Dame. It is the second time Yerrid referenced O'Leary's short tenure at Notre Dame in broad terms in front of the jury.

Tribble said he felt it was important for athletes to be tested for sickle cell trait and for athletes with the trait to be supervised.

He was asked whether it was acceptable to have a certified athletic trainer supervise a workout and not be aware a player in the group had sickle cell trait. Tribble said that would be unacceptable.