Remember when you were little and the school recess bell rang? You and your friends would run outside to the playground, two of you would grab the ends of a long rope and for the next few minutes your voices would sing as you took turns jumping rope.

Well, the time has come to recapture your youthful enthusiasm for jumping rope. This fitness activity is not just for kids. It's a great way to strengthen and shape grown-up legs and give adult hearts a workout.

If it's been 20 or 30 years since you last tried jumping rope, you're in for a few surprises. You probably won't be able to pick up where you left off, even if you were a superstar of the schoolyard. It's going to take a little practice and a lot of patience to become proficient again.

Jumping rope for 15 minutes three to five times a week is an excellent cardiovascular activity. Fifteen minutes may not sound very long, but it may take you several weeks to actually reach a level that will enable you to jump rope continuously and with good form for the entire workout period.

Jumping rope also works the leg muscles -- particularly the calf muscles, which experience considerable contraction while jumping. The lower arms also get a workout -- if you're turning the rope correctly, using mainly your wrist joint rather than your whole arm. More than likely, the lower arm muscles will become stiff when you're beginning a jump rope program, but this discomfort will pass as your conditioning improves.

If the muscles in your shoulder area are sore after jumping, or if they become fatigued while jumping, you're using poor technique. Use your wrist, not your whole arm, to turn the rope. If you feel any pain in your wrists or shoulder joints during or after jumping, you should lower the intensity of your workout. Continued aggravation of these joints can cause injury.

Check your posture before you begin jumping. Keep your torso erect, contract your abdominal muscles and tuck in your pelvis. Your knees should be slightly bent. If you bend at the waist, it will be much more difficult to maintain the coordination necessary for continuous jumping. Your feet are also apt to strike the ground with greater force.

To maintain the correct jumping position, your rope must be long enough. It's the right length if the handles reach your armpits when you stand with both feet on the center of the rope and pull it straight up. Most ropes are designed to be easily lengthened or shortened. Always jump with a rope that has handles so you won't experience excessive wrist joint and arm muscle fatigue. When you use the rope, hold your arms away from your body with your elbows bent at a 45-degree angle.

Besides having the right rope length, you must also have good athletic footwear. Rope jumping is a high-impact activity. When you land, the balls of your feet touch the ground with a force of up to two times your body weight, and as you jump up to clear the rope, your upward force may be four to five times your body weight. This kind of stress is similar to that experienced while running. If you use correct form and wear athletic shoes that provide good support and shock absorption, you can reduce the impact during jumping.

While you're jumping, your grip on the rope handles should be relaxed but firm. Beginners tend to hold the handles too tightly, which makes the wrist muscles tight and makes the rope more difficult to turn. A tight grip will also cause the wrist muscles to tire more quickly. Place the handles in the palms of your hands and close your fingers around them, gripping with your fingers only as much as necessary.

Your goal is to make single jumps using both legs, meaning you take one jump per arm turn. If you're an unskilled jumper, you may tend to double jump -- you jump to clear the rope and then as it's overhead you jump again. Double jumping will make it more difficult for you to increase the number of jumps you can do per minute, thereby limiting the intensity of your workout.

What if you try a few jumps and before you know it, you've tripped over the rope and have to stop? Here are some easy tips to get you doing continuous single jumps at a relaxed speed.

Stand in front of a mirror, holding the rope in one hand, and without turning it, jump easily and continuously over an imaginary rope. Now twirl the rope on one side of your body and jump as if you were jumping the rope. Continue twirling and jumping until you have a sense of rhythm to your jumping. You'll see how easy it is to jump. Now hold the rope with two hands and try to duplicate the rhythm while you actually jump the rope.

Listen to the sound of your feet hitting the floor, or have a friend watch you and listen. You may hear several quiet landings, followed by an occasional loud thud. This means you are losing your coordination while jumping and driving your feet into the floor to try and gain control of your rhythm. If this is the case, practice jumping more without the rope, holding it in one hand and turning it while you jump.

If you hear continuous loud thumping, you may be lifting your feet too high off the floor and landing with greater impact. You only need to lift them high enough to clear the rope. If you're doing this, it's important that you change your technique or you'll risk injury. Again, practice jumping while turning the rope in one hand until your feet are landing in a quiet, rhythmic manner.

Have your jumping partner watch your posture while you jump. In particular, have your partner check that your torso is erect (no bending at the waist) and that your knees are slightly bent to help absorb the impact.

You're going to get very tired when you first try jumping rope, especially if you haven't had a regular program of exercise. Even as you progress and can do single jumps for the full 15 minutes, you're going to get a little bored just doing one style of jumping all the time. Also, if you always do the standard single jump style, you'll tire more quickly because you're continually using the same muscles.

To build up your strength and to keep you interested in your program, vary your jumping routine. You can warm up by stretching with the rope, jumping while turning the rope on the ground and hopping from side to side over the rope. If you're a beginner, you can maintain your cadence by jumping for a while and then alternating your jumping with a rest period of marching in place while twirling the rope in one hand.

As your jumping skills improve, vary your style. Try jumping on alternating legs, kicking your leg in front of you, kicking your leg to the side or lifting alternate knees while jumping. When you were a child, your favorite jumping rhymes kept you going. Listening to music can keep a mature rope jumper just as motivated, so try turning on your stereo during your workout.

Jumping rope is a vigorous form of exercise and, although it's a lot of fun, it's not for everyone. If you're over age 35, sedentary and overweight and you want to start a rope jumping program, check with your doctor first. Jumping raises your heart rate and puts stress on your joints, so if you have a joint injury or any heart or circulatory problems (such as high blood pressure) you should choose a less stressful aerobic activity such as swimming or walking. Again, be sure to check with your doctor first.

Try making rope jumping part of your regular aerobic workout. It's a lot of fun and one of the world's most convenient fitness activities. If you travel, what could be easier than packing your jump rope for the trip? By following a sensible program and using good jumping technique, it won't be long before you're jumping rope like a schoolyard superstar once again.