Thinking of buying one of those exercise machines you see advertised? They make great towel racks but few people stick with them. The movements are often unnatural and do little to train your muscles. The good news is your body is the only equipment you will ever need to shape up and slim-down.

Before training with weights became the standard we used to call exercises that you did with only your body calisthenics. They are exercises that use the resistance of your body weight to increase your strength and reduce your excess fat. They are still the best way to build real-life functional strength. Best of all, they are free and don't take long to do.

I've seen patients transform their bodies through the power of calisthenics. You too, can see improvements in your appearance and in your stamina. And, by doing regular calisthenics, you will be lowering your risk of injury and building muscle that has been trained for function.

* Size versus Strength *

The most efficient way to increase your muscle mass is through resistance training. Methods for resistance training include free weights, weight machines and isometrics. For some of my patients who have lost muscle mass, I whole-heartedly urge them to use the resistance training machines. But weights are not the best way to build functional strength. By functional strength, I mean strength that you can use in real life situations.

Good old-fashioned calisthenics are the safest and most beneficial functional strength builders. With improved functional strength, you will find greater ease in performing routine physical tasks. What's more, you can do calisthenics at home, in the office or while you are on the road.

I have also found calisthenics to be surprisingly effective for trimming down your physique. You can do them in short intervals fitting into your P.A.C.E. program. See Health Alerts 58, 133 and 150 for more tips.

Exercising for long durations is a waste of time. Every time you exercise, you train your body how to use energy efficiently. Your body anticipates future energy needs and adapts by storing fat for future energy needs.

You will burn greater amounts of fat by exercising in short bursts. Repeatedly exercising in ten-minute sessions retrains your body to store energy for fast access. Your body will realize that storing energy as fat is inefficient. This is because you never exercise for long enough to make good use of the fat. In addition, compact exercise routines force your body to burn fat during the muscle recovery process.

* Training for Strength You Can Use *

In real life, you muscles have to handle your own body weight. This makes calisthenics the perfect exercise for training functional strength. They mimic real movements building strength and balance as they train your body and mind. You can do them in short bursts of 10-minutes or less. They do not require expensive equipment. You can do them anywhere or anytime. And, you can exercise muscle groups in the patterns of movement they were designed for with simple maneuvers.

Calisthenics are, however, harder than they look. It will take several sessions to build up your stamina. Start slowly. Take plenty of time to build up your strength, endurance and balance gradually.

Here are a few of my favorite callisthenic exercises:

• Push-ups: Start face down on floor, palms against floor under shoulders, toes curled up against floor. Push up with arms keeping a straight line from head through toes. Lower to within a few inches of floor and repeat. This exercise is great for your entire upper body.
• Squats: Stand with feet shoulder width apart. Squat as far as possible bringing your arms forward parallel to the floor. Return to standing position. Repeat.
• Knee bends: Start with your feet almost together and arms at your side, head straight and level. Lower your body by bending your knees until your thighs are parallel to the floor, rising up on your toes, while simultaneously swinging your arms forward until they are parallel to the floor in front of you, fingers together and palms facing down, and back remaining perpendicular to the floor. Without stopping, reverse this motion and return to your original starting position. Repeat.
• Jump squats: Start with your body crouched, feet together, arms at your sides, head straight and level. From this position, quickly straighten your legs and jump upward as high as you can into the air, simultaneously extending your arms and reaching overhead. Once you have landed, quickly return to your original starting position, taking care not to lose your balance throughout the exercise.
Should you feel any pain, dizziness or shortness of breath slow down. You do not want to over exert yourself. Adding calisthenics to your days will make significant improvemnts to your health and level of fitness.The word calisthenics comes from the Greek words 'kallos' for beauty and 'thenos' for strength. I hope you make your body stronger and more beautiful by practicing callisthenic exercises.

Al Sears, MD