It was Sept. 24, 2006, the day after the Rice football team suffered a humiliating 55-7 loss to Florida State. Rice coach Todd Graham cancelled practice for most of the team, but Lloyd and other underclassmen who didn't play much against FSU were told to report for Sunday conditioning.
Lloyd and his teammates ran 16 consecutive 100 yard sprints – almost a full mile. Early on, Lloyd started showing signs of distress, breathing heavily and suffering muscle tightness in his legs. As the workout progressed he had trouble standing. Later, he even had trouble just holding up his head.
Lloyd was always known as a hard worker both in the classroom and on the field, but as the sprints continued some of his teammates became concerned about his condition. He was normally one of the team's fastest players, but that day he lagged 30 to 40 yards behind teammates, including the bulky offensive linemen. He ran with his head down, clutching his sides in pain.
Some witnesses said when Lloyd's teammates tried to help him, an assistant strength and conditioning coach ordered them to leave Lloyd alone. He finished 16 full sprints before collapsing. He never regained consciousness.
A medical examiner later determined Lloyd died on Sept. 25, 2006, from complications of sickle cell trait.
Since 2000, nine college football players have died from sickle cell trait complications, by far the biggest non-traumatic killer in the sport. The list includes UCF wide receiver Ereck Plancher after an offseason workout in March 2008. Last month, a jury found the UCF Athletics Association negligent in Plancher's death and awarded his parents $10 million.
At least 17 high school and college athletes' deaths have been tied to sickle cell trait during the past 11 years. The group includes Olivier Louis, a player at Wekiva High School near Orlando, who died on Sept. 7, 2010, following his first football practice.
Ereck Plancher's father, Enock, said he does not understand why these deaths have not caused more outrage or prompted more changes to protect athletes.
"Football is sport," he said. "It's not supposed to kill you. It has to change."
What is sickle cell trait?
Every hospital in the United States is required to test newborns for sickle cell trait. The state of Florida began testing in 1988.
Testing was started to help determine which children have sickle cell anemia, a debilitating blood disease that warps red blood cells and can cause strokes, fever and ulcers. The disease typically reduces a person's life span.
People with sickle cell anemia have Hemoglobin S, a variant of two genes that cause flexible doughnut-shaped red blood cells to collapse into rigid crescents or sickles. The cells get sticky, block blood flow and can cause major organ damage.
People with sickle cell trait do not have sickle cell anemia.
Sickle cell trait carriers have Hemoglobin SA, with one gene capable of making warped red blood cells and one that produces normal red blood cells. Most people with the trait typically don't suffer any symptoms or health problems related to the condition.
However, a growing number of medical experts argue sickle cell trait can be a silent killer.
When a person with sickle cell trait is under extreme physical stress — such as during Lloyd's workout at Rice and Plancher's workout at UCF — their blood cells can warp into the flat, rigid sickle cell shape. The sticky red blood cells attack muscle tissue, blocking oxygen flow and quickly shutting down vital organs.
According to a September 2010 New England Journal of Medicine article, the risk of exercise-related sudden death is 10 to 30 times higher among sickle cell carriers than it is among people without the trait.
"We've learned that, under extreme stress, there can be massive, life-threatening complications," said Dr. Jon Thogmartin, the Pinellas and Pasco County chief medical examiner.
Who has sickle cell trait?
Long before sickle cell trait was linked to deaths, it was lauded as a miraculous gene mutation that protected the body againstmalaria.
Africa and the Mediterranean region of Europe have the world's highest rates of malaria exposure.
According to the National Institute of Health, 8 percent of African-Americans in the United States have the trait. Less than one percent of the non-African-American population here carries the trait, including Georgia head football coach Mark Richt's son, David.
The numbers are much higher some places outside of the U.S. A study published in 2004 found about 30 percent of people living near the Congo in Africa had sickle cell trait. Other studies since then have found that about 10 percent of people in Jamaica and 15 percent of people in Haiti have the trait.
As a result, a larger percentage of children of recent immigrants from those regions likely have the trait. The three Florida athletes who died — Florida State's Devaughn Darling, UCF's Plancher and Wekiva High's Louis — were all children of Caribbean immigrants.
After Lloyd's death following the Rice workout, his parents sued the NCAA for failing to require all schools to test for the trait. As a result of a settlement with the family, the NCAA began a screening program last year. All Division I athletes are now either tested for sickle cell trait or must sign a waiver indicating they do not want to be tested.
The NCAA has not released a breakdown of how many athletes tested positive for the trait. However, The Institute for Diversity and Ethics in Sport released a study indicating 11,924 athletes played at the Football Bowl Subdivision level in 2010. Based on the figures, it is likely about 670 players competing at the highest level of college football last season had sickle cell trait.
Sickle cell trait is at the heart of a controversy within the medical community, with one side arguing it sometimes causes sudden death and others arguing it could not possibly cause someone to die.
Critics suggest deaths are incorrectly being tied to sickle cell trait, ignoring issues such as heat stroke and heart problems that are the true causes of death. They suggest any changes to red blood cells occur naturally after a person with sickle cell trait dies because the body is deprived of oxygen.
Thogmartin, the Pasco and Pinellas chief medical examiner, adamantly disagrees.
He recently co-wrote a Journal of Forensic Sciences article documenting 16 people who died from sickle cell trait complications since 1996. He argues pathologists review a long list of factors besides warped red blood cells to determine whether a death could be caused by sickle cell trait complications.
Some critics of the NCAA's sickle cell trait testing policy argue schools may discriminate against athletes who have tested positive for the trait.
In 2007, the National Athletic Trainers' Association said sickle cell trait should not disqualify athletes from participating in sports. Researchers have documented cases of high school, college, pro and Olympic athletes with sickle cell trait who completed their careers with zero health problems cause by the condition. NFL stars Terrell Owens and Santonio Holmes are among a long list of NFL players who tested positive for sickle cell trait but have not suffered any trait-related health problems.
"There's never been any statement or study that I'm aware of that has said that sickle cell trait is a contraindication," said Oklahoma head athletic trainer Scott Anderson, co-chairman of the group that developed the National Athletic Trainers' Association consensus statement on sickle cell trait. "If everyone follows precautions, there is no reason athletes can't perform at the highest levels."
A committee of about 40 people, including 15 doctors and 13 certified athletic trainers, met to develop the NATA's guidelines for treating athletes with sickle cell trait.
The task force recommended the following:
Athletes should gradually increase their training, allowing longer periods of rest and recovery between repetition of exercises. Players should participate in preseason conditioning programs, but they should not be forced to do timed performance tests such as mile runs or 100-yard sprints in rapid succession. If they do the timed drills, the athletes should have long periods of rest between sprints.
Athletes should be instructed to stop if they feel any unusual pain, cramping, swelling, weakness or inability to catch their breath.
Heat stress, dehydration, asthma, illnesses and altitude all can make athletes with sickle cell trait more vulnerable to a sickling collapse. Some supplements and energy drinks can contribute to dehydration, making the athlete more vulnerable to sickle cell trait complications.
Once an athlete begins to show signs of a sickling collapse, the person still can be saved. If the sickled, or warped cells, are exposed to oxygen relatively quickly, they can recover.
"Early and immediate intervention can resolve a small problem," Anderson said.
Coaches and trainers need to be aware that sickle cell trait is unpredictable. Two athletes with the trait can respond differently to the same workouts. And a sickle cell trait carrier can get through an extreme workout on one day and later have problems completing lighter workouts.
A variety of factors, including physical conditioning, hydration levels or a mild cold or allergies might cause one athlete with the trait to struggle more than others.
The task force suggested athletes with sickle cell trait should rest and drink water at the first sign of distress. If the athlete is not recovering, athletic trainers should check vital signs, administer high-flow oxygen and cool the athlete. If the person's vital signs decline, athletic trainers should call 911, attach an automated external defibrillator, start an IV to provide fluids and get the athlete to the hospital quickly.
Despite identifying 16 cases where people have died from trait complications during the past 14 years, Thogmartin said he firmly believes people can live normal lives if they have sickle cell trait.
"If I had it, I would not stop any activity or stop working out," he said. "You have to look at why these cases happen. I'd be careful at high altitudes, I'd be careful if I had a cold and was going on an airplane and I'd understand the steps I should take for treatment.
"But there's a reason these cases happen the most with college football players. There's a reason it happens to the good kids who are trying so hard to please their coaches. There are a lot of people out there with the trait who have self preservation instincts, who stop when they don't feel good. Their bodies recover on their own. It's the people who don't want to give up, who don't want to be anything less than perfect. They're the ones in danger if we don't educate them and their coaches about the trait. They're the ones who are dying."