Nearly everyone who has graduated from high school has memories of playing volleyball, field hockey or basketball during gym class. For almost an hour a day, you would run, jump and play, trying to become proficient in a sport. For those who asked why they had to be there, the answer was always the same. You had to take gym to graduate.

Then there was health class. You had to take that, too.

You were rarely told, however, how gym and health were related, how both were vital to being physically fit the rest of your life. Gym classes in most public schools focused solely on learning the concepts and skills of team sports, and health classes were devoted to topics such as nutrition and drug and alcohol abuse.

But George Mason Junior/Senior High School in Falls Church is piloting a new approach to physical education and health. In a seventh-grade physical education class that meets for 45 minutes a day, five days a week, 12-year-old students are learning how physical fitness is related to overall mental and physical health.

"Academic fitness is related to athletic fitness," said Nancy Sprague, director of instruction at George Mason. "The big debate historically in physical education is how much time to spend on team sports and how much time to spend on lifetime sports. We're taking a whole different approach -- lifetime physical fitness."

In the George Mason gymnasium two weeks ago, Jack Gambill, chairman of the physical education program, cardiovascular teacher and senior high football coach, checked his watch while each student in his class took his or her pulse. Then Mary Lee Tatum, the health teacher, directed the class through relaxation exercises, explaining the physical reactions taking place inside the body when the students breathed deeply, then exhaled. Mable Bradd is responsible for teaching the motor skill activities, such as dribbling a basketball and hitting a softball.

George Mason High, which has only 80 students in grades 6-12, operates on a four-quarter, nine-week basis. After students are introduced to the goals and purpose of the program, they spend three weeks each quarter rotating among three units: a health curriculum that explains the benefits of good nutrition and proper reaction to stress; cardiovascular, strength and flexibility activities that emphasize the effect of exercise on the heart, lungs and muscular system; and motor skill activities that develop hand-eye coordination and abilities through team sports.

"Six out of every nine weeks, they'll have physical activity," said Sprague, 40, who has a doctorate in social science education with 14 years' experience at George Mason. "Maybe it's not the traditional games, but it might be aerobic dancing or square-dancing. The other three weeks, the students study the health curriculum."

The three-week health curriculum emphasizes mental health and stress, and nutrition. The instruction explores the causes and symptoms of stress, the nonproductive reactions to stress, such as suicide, drugs, fighting and smoking, and the productive reactions to stress, including relaxation techniques, exercise and problem-solving.

"We want the kids to walk away continually thinking about and working on athletics and health, strength, and flexibility," said George Mason Principal George H. Thoms. "Traditionally, we're developing better athletes, but there is no concern for flexibility, lower blood pressure, stress management, et cetera. We want our students to be able to read and write and know their bodies and minds as well."

"We've been talking about it the program for a couple of years," said Thoms, 45, who has run 35 marathons in the past eight years and competed in three triathlons this year. "We've been hearing an awful lot about it fitness at meeting and conferences."

A culmination of articles, conferences and an increasing amount of publicity about fitness prompted Sprague and Thoms to combine the health and fitness classes. Sprague said that a 1979 article describing a successful weight loss program for overweight children in the Billings, Mont., public schools has acted as a guideline. In addition, a fitness conference sponsored by the Virginia State Department of Education convinced Thoms of the importance of health and physical education.

During the first week of the new fitness program, the students must complete a physical fitness test, including measurement of height/weight, resting pulse, skinfold, and a mile run. These tests emphasize the relationship between health and physical activity and demonstrate that body measurements can be improved with appropriate physical activity.

The results are mailed home, accompanied by each student's academic grade report, at the end of the first quarter. The students are again tested at the end of the second and fourth quarters, and the results are compared with the pretest data and mailed to parents.

The underlying philosophy throughout the program centers on five health-related topics (cardiovascular, strength, muscle endurance, flexibility and body fitness), six skill-related areas (agility, balance, coordination, power, reaction time and speed), and four concepts to prevent students from overtraining.

Students are encouraged to record and monitor their progress in cardiorespiratory functions (such as running), body composition (lean/fatness) and abdominal and low back-hamstring functions (such as stretching, sit-ups, and chin-ups).

While there has been no feedback from the parents, for the most part the students are pleased with the new course. "The class has made us more aware of bad habits like inadequate diet, lack of exercising, smoking and drinking," said Lachlan Leach, a 12-year-old seventh-grader. "Last year, we didn't do anything interesting in physical education class."

"There have been a wider variety of things to do," said Alex Simopoulos, another student. "We have been learning about our heart and cardiovascular fitness. We run two laps around the track, then stop and take our pulse."

But there has been criticism from the students, too. "I study all day, then I want to run or play soccer," said John Karro.