HOW DO YOU RATE? Whether you're just beginning a fitness program or are already an avid exerciser, self-assessment is an important element in helping you get into the shape you really want to be in.

Try the following easy tests to measure your strength, flexibility and body fat. You won't be measuring your fitness against that of others who differ in sex, size and age. Your only competitor is yourself. Keep a record of your progress, testing yourself every three months.

HOW FLEXIBLE ARE YOU? --

A supple, flexible body is more fit for pleasure, sports, and work and is less injury prone. This test measures your flexibility, especially in the lower back and hamstrings. Flexibility comes with practice, so try this test as often as you feel like it. Record your inch-by-inch progress.

Sit on the floor with your legs extended straight in front of you, heels hip distance apart. Slowly reach your hands forward as far as you can, keeping your legs straight. Record how many inches your fingertips are from your heels, either before or past them. The farther you can reach past your heels the better; just keep trying and you'll definitely improve!

HOW STRONG ARE YOU? --

This test measures upper-body strength -- the strength in your arms, chest and shoulders, which improves your appearance and posture and allows you to perform many tasks, especially those used in many sports, with greater ease. Note: If you have high blood pressure, do not try this test.

With hands shoulder-width apart and your palms flat on the floor, support yourself on your hands and (for men) the balls of your feet, or (for women) your knees, with lower legs bent up at a 90 degree angle. Your body should form a straight line from head to heel or knee. Maintaining this alignment, bend your elbows, lowering your body until your chest almost touches the floor. Raise yourself to the starting position, extending your arms fully. See how many push-ups you can do in 60 seconds and record the results. If you can do 25, terrific!

HOW TRIM ARE YOU? --

"For every inch the waistline exceeds the size of the chest, the potbellied person can deduct two years from how long he can expect to live." -- Metropolitan Life Insurance Company. Excess body fat is recognized by the American Heart Association as a major factor in heart disease. Ideally, a man's waist should measure at least five inches less than his chest. A woman's waist should measure at least five inches less than her girth at a point just below the bustline. Here's my quick body-fat test:

With the thumb and forefinger of one hand, pinch the skin two inches to the side of your navel. There should not be more than a half inch of fat between your thumb and forefinger. Men should also pinch the fat spots on the back of their middle upper arms and on their chest two inches above and outside the nipple. Women should also pinch the fat spots on the back of their middle upper arms and the backs of their thighs about four inches below the buttocks.

If you need to reduce body fat, you should not attempt to do so by restricting calorie intake alone, but by a proper balance between calories consumed and calories burned through exercise. Dieting alone slows your metabolism, making fat loss difficult and causing fatigue. Exercise speeds up metabolism and burns calories.

Write to Denise Austin c/o Weekend, 1150 15th St. NW, Washington DC 20071.