Tom gets out of school this week. He can't wait.

"No more pencils, no more books, no more teachers' dirty looks!" the kids in Tom's school yell when they're out on the playground during recess. Tom yells, too -- even though his teacher is really nice, and he likes her a lot.

In class a few days ago, Tom's teacher gave her students one last homework assignment.

They all groaned. Tom groaned, too -- even though he secretly thought the assignment sounded more like fun than work.

Here's the assignment. You might enjoy trying it, too. Interview the oldest member of your family -- your grandmother or grandfather, or a great-aunt or uncle, or even a great-great-grandparent. Ask the relative to describe what summertime was like when he or she was your age.

Tom talked to his grandfather, who's in his late seventies. The next day, Tom told his class about what he had found out.

"My grandfather was busy in the summer," Tom reported. "He grew up on a farm in Pennsylvania. He got up early and had a huge breakfast. I would pop if I ate that much! Then he would milk cows. Later he helped out in the fields. Haying was the busiest time. My grandfather helped load the bales of hay onto a truck. At the end of the day, he and his cousins ran down to a creek to wash off the itchy hay. They swam and fooled around for a while. Then they ate dinner, and went to bed early. They didn't watch TV at all. In fact, TV wasn't even invented yet!"

Tom's teacher listened to the reports. Then she said, "It sounds like most of your relatives were physically fit kids," she said. "You have to be strong and have endurance to do something like lift bales of hay."

"I'll find out this summer," Tom said. "I'm going to an Amish farm for a week with my family. We're going to live like the Amish do, and share all their chores. I hope I'm physically fit enough to do it." Are you physically fit enough for all the activities you have planned for the summer? According to recent studies, there's a pretty good chance that you're not as physically fit as you could -- and should -- be.

This spring, the President's Council on Physical Fitness and Sports released the results of a nationwide survey. The researchers gave fitness tests to 18,857 boys and girls, age 6 to 17, from 57 school districts and 187 schools around the United States. It was the largest school fitness survey of its kind ever done.

Here are some of the results: Forty percent of boys age 6 to 12 couldn't do more than one pullup; one out of four boys couldn't do any pullups at all. Seventy percent of all girls tested couldn't do more than one pullup; 55 percent couldn't do any. Forty-five percent of all boys and 55 percent of all girls couldn't hold their chins over a raised bar for more than 10 seconds. In the 50-yard-dash, 10-, 11-, 14- and 16-year-old girls were slower than girls the same age who were tested back in 1975. Forty percent of boys age 6 to 15 couldn't reach their toes when they were sitting on the ground with legs outstretched. About 50 percent of girls age 6 to 17 and 30 percent of boys age 6 to 12 could not run a mile in less than 10 minutes.

Former Redskins football coach George Allen, who is the chairman of the President's Council on Physical Fitness, says: "This survey shows that there are some major problems in physical fitness among the youth of this country. Many children simply aren't getting the vigorous exercise they need to develop strong and healthy bodies."

You don't have to be an expert to figure out what might be causing the problem. Compared to the way people lived in your grandparents' generation, today's kids live soft, easy lives. They ride the bus to school; when they visit friends or go shopping they are driven there by car. They spend many, many hours a week watching TV -- often with fattening snacks nearby. They go to malls and play video games, which exercise only the wrist, not the whole body.

With all these easy things to do, it's sometimes hard to get excited about playing outside and working up a good sweat and a set of tired, well-exercised muscles.

Motivation, writes Coach Allen in a booklet called "Get Fit!," is an important part of an exercise plan. Being motivated means having a reason or a stong desire to do something. In other words, to succeed at an exercise plan, you have to want to succeed. The President's Council thinks motivation is important too. So they asked Olympic gymnast Mary Lou Retton to help motivate some kids who took the National Youth Physical Fitness Test in Washington, D.C., last month. The energetic gymnast really got the kids fired up to improve their bodies.

But most of you won't have someone like Mary Lou Retton around to keep you exercising this summer. You'll have to set your own goals and keep track of your own progress. Keeping a record of your exercise can help. You can use the chart on Page 15 to keep a record. Put in on your refrigerator or bulletin board in a place where you'll see it every day, and it will remind you to get moving.

"Don't make the mistake of thinking that because you're active, you're physically fit," writes Coach Allen in "Get Fit!" The book is designed to help kids prepare for the National Youth Physical Fitness Test. It tells you how to do exercises especially designed to get you in shape for the fitness test. You can order "Get Fit!" from The President's Council on Physical Fitness and Sports, Department 56, Washington, D.C. 20001. While supplies last, they will send you one for free. What is the National Youth Fitness Test? Millions of American kids have taken it over the last 20 years. You may have already taken it in your gym class at school, or at a local YMCA, YWCA or community center. The test measures how well your body reacts to strenuous conditions, and how well you compare with other kids your age. It evaluates your strength, endurance, flexibility, speed and agility. Passing the test means you have a very good level of fitness.

To get in shape this summer, Ash E. Hayes, the executive director of the President's Council on Physical Fitness and Sports, recommends taking part in an organized sports program at a recreation department, camp or club. You might try a soccer clinic, a tennis camp, or swimming lessons. If you can't or don't want to join in organized sports, you should still get lots of outdoor exercise, Hays says.

"Get a balance of reading and TV watching and vigorous play this summer," Hays says. "If you have a chance, learn a sport that you've never tried before."

Hays, who is a specialist in physical education and taught for many years, says that physical fitness has four parts:

1. Heart and lung endurance.

2. Muscle strength.

3. Muscle endurance.

4. Flexibility.

"Each of these four has to be developed a little differently," he says. "For heart lung endurance you have to do something that raises the pulse rate and keeps it there long enough to have a training effect -- at least 15 minutes."

For muscle strength you have to do activities that make the muscles work. "Gymnastics is a great activity," Hays says. "Not only will you develop strength, you'll get more confidence. And after all, someone has to replace Mary Lou Retton as the country's most famous gymnast someday."

For muscle endurance, you need to do repeated movements, Hays says. "If you do one pullup, that's muscle strength. But if you do 25, that's endurance."

Flexibility is how limber the joints are in your body and how far they will allow the body to move. For example, very flexible people like Mary Lou Retton can stand up and touch the palms of their hands to the floor without bending their knees. Kids are naturally more flexible than adults. But it's still a good idea to work on flexibility so you can keep active as you grow older. The best way to develop flexibility is to do slow, stretching exercises -- the kind you do during a warm-up.

The President's Council on Physical Fitness and Sports is 30 years old this year. President Dwight Eisenhower founded it after a doctor in New York published a study saying that American kids were not as fit as children in western Europe. All the presidents since then have supported the program. Sometime this year, someone will earn the 8 millionth President's Physical Fitness Award. Maybe it will be you!

When you exercise this summer, be sure to warm up before you start by doing slow, careful movements. Work hard enough so that you can feel it in your muscles, are breathing more deeply and have worked up a sweat. But stop before it hurts!Cool down at the end by stretching and slow walking. Remember to drink lots of water to replace the liquid you lose when you sweat. Try to exercise every day, or every other day at least.

To win the Presidential Physical Fitness Award, you have to finish in the top 15 percent of kids your age. The events you have to take part in appear on the chart on Page 14. Each winner gets a certificate and an emblem to sew on a jacket or sweater. The emblem has the American eagle on it.

Starting this fall, kids between the ages of 6 and 9 will be eligible for the award. In the past, you had to be 10 to try for it. You can take it every year until you're 17, because there are different requirements for each age group. If you don't win, you get another chance to try the next year. If you don't win, don't be disappointed. An average of 18 million kids try every year, but only 370,000 win the award.

Dr. Paul Dyment, who represents the American Academy of Pediatrics' committee on sports medicine, thinks lifetime fitness is an important health goal for America's kids. The AAP is a group of 28,000 doctors interested in making kids as healthy as possible.

"Fitness is more than athletic ability," he says. "It is the optimal functioning of the heart, lungs, and blood vessels." He means that you are most fit when your heart, lungs, and blood vessels are working their best.

Dr. Dyment feels that the two best lifelong fitness sports are tennis and soccer, followed by swimming and running. Now that summer's here, why not plan to make one of these sports part of your routine?

Tom's planning to. After he gets back from the Amish farm, he and his brother are going to a tennis camp. Then, before school starts, they have a soccer clinic to attend. What are your summer fitness plans?