A 16-year-old McLean High School football player died yesterday morning after collapsing on a school playing field during the team's first workout of the season.

David L. Robinson, of the 2800 block of Hollywood Road near Falls Church, was participating in a light workout with the rest of the team at about 10:15 a.m. when he suddenly crumpled to the ground, school officials said. Two trainers administered cardiopulmonary resuscitation to the junior before he was flown by helicopter to Fairfax Hospital, where he died about 11:40 a.m., hospital officials said.

Robinson, who was 6 feet 2 and weighed about 270 pounds, was the first Washington-area high school student to die following school-sponsored athletic activity since a Linthicum, Md., student died of an enlarged heart during a basketball game more than three years ago.

Robinson, a tackle for the McLean Highlanders, played frequently last year and was expected to be one of the better players this year, according to Bruce Patrick, athletic director for Fairfax County Schools.

"I looked at the practice schedule and it was very, very reasonable for the first day," Patrick said. "I was a coach a number of years and I thought it was an excellent first-day workout schedule. As far as safety precautions go, I know they did everything possible that could have been done for the young man."

Hospital officials said they did not know the cause of death yesterday. Police said an autopsy would be performed, possibly as early as today.

According to a study by a University of North Carolina researcher, eight high school students died nationwide last year from some form of heart failure indirectly related to sports activities. Two students died from heatstroke.

Kathryn Kenders, one of Robinson's emergency room doctors, said Robinson did not have a heartbeat when he arrived at the hospital, although doctors continued to work for about an hour to revive him.

Kenders said that often when large, muscular athletes die suddenly during a workout it is caused by an irregular heartbeat that leads to loss of blood to the heart. The condition is sometimes brought on by hot weather.

Robinson was wearing a lightweight jersey, shorts and a football helmet, said county fire department spokesman Michael T. Reilly. When the workout started after 8 a.m. the temperature was 75 degrees with humidity of 83 percent at Dulles International Airport; temperature and humidity were not at critical levels, a national weather service spokesman said.

Yesterday was opening day of practice for Virginia high school football teams and Patrick said consequently the workout was light. Students do not wear heavier clothing and pads until later in the training season, he said.

"They were running through plays and sprinting 20 to 30 yards downfield before returning to the huddle," Patrick said. "They were about 30 minutes from concluding the workout" when Robinson collapsed.

Patrick said Robinson had sprinted down the grassy, tree-bordered field and was coming back to the huddle when he fell. Two school-certified trainers on duty at the practice ran to Robinson's aid and asked him a few questions, suggesting he was conscious, Patrick said.

The two trainers performed CPR until an ambulance arrived.

Patrick said Robinson was given and passed a standard physical examination Saturday, as required by the state, administered at a branch of Group Health Association in Fairfax. The examination does not include heart monitoring, Patrick said.

"We have guidelines for heat, the duration of practice, what they can wear and fluid consumption," Patrick said. "This was not a heavy activity practice. The bottom line is that I feel very comfortable in that we have a very safe and healthy environment. I am deeply saddened."

Yesterday was the first day of coaching for the McLean football coach, Karl Buckwalter, a 1981 graduate of McLean and a former assistant coach at the school. "He's young and he was torn up," Patrick said of Buckwalter. "It's a very tough situation for him to have something like this happen."

Buckwalter was not available to comment.

Reilly said counselors and a chaplain had been called to the school yesterday morning to talk to Robinson's teammates.

Principal Elizabeth Lodal addressed a somber group of 60 to 70 students, parents, administrators and coaches at a hastily called 20-minute meeting in the school auditorium last night. Lodal said she had looked forward to seeing Robinson in the hallway. "I knew he'd have a joke," she said. "David loved football. He was incredible, committed to being very, very well-prepared."

She said Robinson had worked out during the summer and that his parents told her he worked for a landscaper in the heat and humidity. She added the players had been given water breaks every 10 to 15 minutes of the morning practice.

"This is every parent, principal and coach's nightmare," Lodal said.

Robinson's family and friends were stunned and distraught. Friends gathered on the steps and benches outside his family's apartment near Lee Highway in Merrifield, many crying and unable to speak.

Robinson's father, David Marsh, said that Robinson was one of seven children, but said he did not want to speak any more about his son yesterday. A neighbor, Ferdinand Graham, said he saw Robinson Sunday evening, walking down the street.

"He always took a walk for exercise," Graham said. "He was always playing with the smaller kids, taking care, like that. He was a very nice kid, always pleasant with everybody."

Three years ago, Andover High School senior Jonathan Ausby III, 17, died during halftime of a basketball game from an enlarged heart. Two months earlier Potomac (Va.) High School football player Charles Coles, 16, died from a difficult-to-detect heart defect during a game. In September 1987, John Avila, two-way starter for Stuart High School, collapsed during a game with a blood clot caused by ruptured veins between his skull and brain. He has been in a coma since.