The researchers assessed the physical fitness of 3,287 children aged 12 to 19 who participated in the National Health and Nutrition Examination Survey between 1999 and 2002. The children were interviewed before going to a mobile examination center. There, they exercised on a treadmill for a two-minute warm-up, two three-minute exercise periods, and a two-minute cool-down period.
The researchers measured blood pressure, heart rate and rate of perceived exertion during the tests, and also asked the children to rate how hard they felt they were working their bodies. During the exercise periods, the children's heart rates were used to determine the approximate amount of oxygen used by their bodies during maximum exertion.
The results of the test showed that only about 65 percent of the kids were judged physically fit.
"We are concerned, from a public health standpoint, that a third of kids don't meet fitness standards," said lead researcher Russell R. Pate, a professor of exercise science at the University of South Carolina's Arnold School of Public Health in Columbia. "The solution is for American youth to be more physically active than they are right now."
According to the report, boys tended to be in better shape than girls; older boys tended to be in better physical shape than younger boys; younger girls tended to be in better shape than older girls; and, unsurprisingly, the heavier children were in poorer shape than the slimmer children. It was also determined that children who spent a lot of time watching television, playing video games, or generally avoiding physical activity were less likely to be fit.
"Kids need to be involved in more quality after-school sports programs," Pate said. "More kids need to be provided with physical-education classes in their schools." Pate added that children should make physical activity part of their everyday lives -- walking or riding bikes to school, for example. "This is going to call for some major changes in the way our society is organized and in the expectations that we have of ourselves and our children," he said.
Health expert Dr. David L. Katz, an associate professor of public health and director of the Prevention Research Center at Yale University School of Medicine, said that the responsibility for increasing the physical activity of America's children also falls to both parents and schools.
"The links between overweight and poor physical fitness are especially ominous in light of the steadily rising rate of childhood obesity in the U.S. and much of the world," Katz said, noting that current American culture encourages ducking activity and overeating through things like laborsaving devices, marketing, and processed foods being made available just about anywhere at just about any time. "To counter this, we need a force that is not just opposite, but equally strong," Katz said. "We need to find creative ways to get physical activity into the school day every day. We need parents who engage their children in physical activity by making it part of the family routine. We need neighborhoods that provide recreational facilities and parents who set limits to TV and computer time and send their kids out to play."