There are three components of fitness: strength, flexibility and cardiovascular capacity. It takes all three to be truly fit. Physical fitness isn't just about how much you can lift or how far you can run. To gauge your own fitness level, you need to be tested for each component. Find out if you're truly fit with these tests:

FLEXIBILITY

The flexibility of tendons and muscles determines how freely you can move your joints.

Why it matters: "As we become less flexible, we become less functional. Things like reaching or turning your neck when driving to see the car behind becomes difficult. So it's more than just quality of life — it affects your ability to function," explains Mitchell H. Whaley, professor of exercise science at Ball State University in Muncie, Ind.

Take the test: Grab a yardstick and sit on your living room floor with your legs extended in front of you, allowing about 12 inches between your feet. Place the yardstick between your feet so that it points away from you. Line the soles of your feet up to the 15-inch mark. Slowly bend forward with your arms extended, reaching as far past your ankles as you can.

Men

17 inches: above average

15 inches: average

14 inches: below average

Women

19 inches: above average

17 inches: average

15 inches: below average

STRENGTH

Experts call this muscular skeletal fitness — testing muscular strength and muscular endurance. Strength training builds and maintains muscle mass and strong bones.

Why it matters: Muscle strength and endurance also make you more functional. For instance, maybe you can't move your own body weight in and out of a chair or can't carry groceries to and from your car. The more body strength you have, the fewer potential injuries from these activities.

Take the test: The crunch test is a popular method of assessing your abdominal strength, but make sure you do it right.

Lie on your back with your knees bent and your feet planted firmly on the floor. Press the small of your back down and then lift your upper body until your shoulder blades are off the floor. You can tuck your hands behind your head to support it, but don't pull up with your arms — you can injure yourself that way. Instead, focus on using your constricted abdominal and back muscles to complete the crunches. How many can you do without resting?

Men

Excellent:

• 25 (ages 20-69)

Good:

• 16-24 (ages 20-29)
• 15-24 (ages 30-39)
• 13-24 (ages 40-49)
• 11-24 (ages 50-69)

Fair:

• 11-15 (ages 20-29)
• 11-14 (ages 30-39)
• 6-12 (ages 40-49)
• 8-10 (ages 50-59)
• 6-10 (ages 60-69)

Needs improvement:

• 10 (ages 20-39)
• 5 (ages 40-49)
• 7 (ages 50-59)
• 5 (ages 60-69)

Women

Excellent:

• 25 (ages 20-69)

Good:

• 14-24 (ages 20-29)
• 10-24 (ages 30-39)
• 11-24 (ages 40-49)
• 10-24 (ages 50-59)
• 8-24 (ages 60-69)

Fair:

• 5-13 (ages 20-29)
• 6-9 (ages 30-39)
• 4-10 (ages 40-49)
• 6-9 (ages 50-59)
• 3-7 (ages 60-69)

Needs improvement:

• 4 (ages 20-29)
• 5 (ages 30-39)
• 3 (ages 40-49)
• 5 (ages 50-59)
• 2 (ages 60-69)

Source: Adapted from American College of Sports Medicine Guidelines, 7th Edition and from the Canadian Society for Exercise Physiology

Take the test: The pushup test gauges upper-body strength.

Start from the up position with your arms almost fully extended, palms flat on the floor and a little more than shoulder-width apart, balancing on your toes with your feet together. (If you can't do a standard pushup, put your knees on the floor instead of balancing on your toes.) Keeping the pace slow and steady, bend your arms to lower your body — keep your body straight and don't let your stomach touch the floor. See how many you can complete before resting.

Men

Excellent:

• 36 (ages 20-29)
• 30 (ages 30-39)
• 25 (ages 40-49)
• 21 (ages 50-59)
• 18 (ages 60-69)

Good:

• 22-35 (ages 20-29)
• 17-29 (ages 30-39)
• 13-24 (ages 40-49)
• 10-20 (ages 50-59)
• 8-17 (ages 60-69)

Fair:

• 17-21 (ages 20-29)
• 12-16 (ages 30-39)
• 10-12 (ages 40-49)
• 7-9 (ages 50-59)
• 5-7 (ages 60-69)

Below average:

• 16 (ages 20-29)
• 11 (ages 30-39)
• 9 (ages 40-49)
• 6 (ages 50-59)
• 4 (ages 60-69)

Women

Excellent:

• 30 (ages 20-29)
• 27 (ages 30-39)
• 24 (ages 40-49)
• 21 (ages 50-59)
• 17 (ages 60-69)

Good:

• 15-29 (ages 20-29)
• 13-26 (ages 30-39)
• 11-23 (ages 40-49)
• 7-20 (ages 50-59)
• 5-16 (ages 60-69)

Fair:

• 10-14 (ages 20-29)
• 8-12 (ages 30-39)
• 5-10 (ages 40-49)
• 2-6 (ages 50-59)
• 2-4 (ages 60-69)

Below average:

• 9 (ages 20-29)
• 7 (ages 30-39)
• 4 (ages 40-49)
• 1 (ages 50-59)
• 1 (ages 60-69)

Source: Adapted from American College of Sports Medicine Guidelines, 7th Edition, and from the Canadian Society for Exercise Physiology

CARDIOVASCULAR CAPACITY

The term cardiovascular system refers to your heart and blood vessels, which carry oxygen and other nutrients throughout your body. Your cardiovascular fitness determines how easily your body brings oxygen to your lungs and blood to your heart.

The most precise cardiovascular test is the Maximal Oxygen Consumption test, which measures the amount of oxygen you are capable of consuming while working out. And because it's complicated, field tests try to predict what this lab test measures.

Why it matters: The heart is a muscle, and like any other muscle, you can strengthen it with exercise and reduce your risk for disease (e.g. cardiovascular disease).

Take the test: Anyone can take the Rockport Test, says Patrick Hagerman, a professor of exercise science at the University of Tulsa. "It doesn't take an examiner or any special equipment, just a flat terrain like your street. Measure the distance using a pedometer or the odometer of your car." Then cover the mile. Keep track of how long it takes you and what your heart rate is at the end. Then use the following formula to estimate your VO2 Max (maximum oxygen consumption).

Keep in mind that just because you score well on any one of these tests doesn't mean you will have reduced risk for disease or injury. You still need the recommended minimum of 30 minutes' physical activity daily to reduce your risk for disease, says Whaley.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.