You don't have to be a bodybuilder or professional athlete to reap the benefits of a weight training program. Weight training — a form of strength training — can improve your strength, increase your muscle tone, help you lose fat and gain muscle mass, and improve your bone density.

But if done incorrectly, weight training won't give you these benefits and can lead to injury.

This may seem like common sense, but according to Edward Laskowski, M.D., a physical medicine and rehabilitation specialist at Mayo Clinic, Rochester, Minn., and co-director of Mayo Clinic's Sports Medicine Center, most people learn their weight-training techniques by watching friends or others.

A study by Dr. Laskowski and colleagues on weight-training injuries, published in the February 1998 and March 1998 editions of The Physician and Sportsmedicine, reported that incorrect technique is one of the main factors contributing to injuries. Fortunately, most of these injuries aren't life-threatening.

Note the difference between proper and improper technique in these videos demonstrating the most common weight training exercises and the abdominal crunch.

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Common injuries that can occur during weight training include:

• Sprains
• Strains
• Tendinitis
• Fractures
• Dislocations

Over time chronic injuries can occur, especially with improper technique and overuse. Chronic injuries include:

• Rotator cuff damage
• Muscle overload
• Bone stress injuries
• Nerve damage

Other contributing factors for injuries include:

• Lack of supervision
• Skeletal immaturity
• Steroid abuse

If you're just getting started, consider working with a personal trainer. Physical therapists, athletic trainers, and fitness and exercise specialists who have been specifically trained in weight-training technique can help you develop proper technique. Their training may include certification by the American College of Sports Medicine.

Here are more tips to keep you safe and on track with your weight-training program.

• Check with your doctor. If you're older than 40 and inactive, talk with your doctor before starting a weight training program.

• Set goals. Make sure you and your personal trainer have a clear reason why you're doing each exercise and an overall goal for your program. Weight training for muscle toning and overall fitness is different than weight training for a particular sport or activity. Each requires a unique type of exercise tailored to your overall goal and fitness needs.

• Breathe. Don't hold your breath. Your blood pressure can increase during weightlifting to dangerous levels if you hold your breath. Exhaling during the lift and just plain breathing freely during your weight-training exercise can prevent this.

• Seek balance. Work all your major muscles — abdominals, legs, chest, back, shoulders and arms. Strengthen the opposing muscles in a balanced way — front of the shoulder as well as back of the shoulder, for example.

• Lift an appropriate amount of weight. The amount of weight you lift should make your muscles feel tired after 10 to 15 repetitions. A weight that causes fatigue at 12 repetitions is an effective stimulus for muscle strength and toning.

• Don't spend too much time on it. You only need to do one set of exercise to the point of muscle fatigue to obtain benefits. Additional sets aren't necessary. They eat up your time and may contribute to overload injury.

• Don't rush. Don't jerk the weight up. Lift and lower the weight in a slow, controlled fashion. This helps you improve body stabilization, isolates the muscles you want to work more effectively, and doesn't let you cheat by relying on momentum to lift the weight.

• Rest. Give your body a day to recover between workouts of the same muscle group.

• Be consistent. Three workouts a week will build muscles and just two will maintain the strength you've gained.

• Wear shoes. They not only help protect your feet from dropped weights but can also keep you from slipping during a lift and give you a firm foundation.

• Store your weights properly. Keep them away from children. Also watch the way you lift weights out of the rack. Keep your spine stable and lift with your whole body.

  "Some of the worst lifting technique I've seen is when people pick up weights to do their exercise," says Dr. Laskowski.

You want to maximize the benefits of your weight training program. You also want to avoid injury. Use proper technique to reach your goals.