WASHINGTON - The typical U.S. teen isn't playing basketball at a local park, hiking trails or even walking home from school. The typical U.S. teen isn't following a healthy diet, either.

A new study from the National Institutes of Health found that only half of U.S. adolescents are participating in physical activity five or more days a week, and that only 1 in 3 eats fruits and vegetables daily.

The survey queried 10,000 students from 39 states who were 11 to 16 years old; it asked about their physical activity, the amount of time they spent in front of computer or television screens and their intake of unhealthy food.

The researchers also examined the correlation between students' emotional health and their levels of physical activity.

"Only about 1 in 4 kids are exhibiting the healthful pattern that we'd like to see, which is high physical activity and high fruit and vegetable intake and lower consumption of snack food," says Dr. Ronald J. Iannotti, a researcher at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, which is part of the NIH.

"When we looked at the correlates of these patterns, it became obvious that the more healthy group was psychologically more healthful as well."

The study divided students into three categories:

• Nearly half - 47 percent - were what researchers deemed typical. Iannotti said the concern with these teens was a small amount of physical activity and a lack of fruits and vegetables.

Today's teens are "remarkably unhealthy," said Dr. Ann M. Davis, a professor of pediatrics at the University of Kansas Medical Center. "They are extremely sedentary and they have terrible diets for a variety of reasons."

NIH researchers found that these typical adolescents were more likely to be obese than those in the other two groups.

• Unhealthful students composed 26 percent of those surveyed. They tended to spend the most time in front of computer screens and exhibited the worst eating habits, consuming more sweets and fewer fruits and vegetables than the other groups in the study.

These students were more likely to report symptoms of depression and poor physical health.

• Healthy students accounted for 27 percent of those interviewed.

Students in this group were the least likely to spend significant time in front of computer screens and were the least likely to consume sweets, soft drinks and chips. Nearly 65 percent of the students in this group reported exercising more than five days a week.