Editor’s Note: Following is the third in a 12-part series of columns from Eastern Maine Medical Center in Bangor. Move & Improve is an outreach program, promoting healthful lifestyles for Maine people, of EMMC’s Community Wellness Service.

By the age of 70, most Americans will lose about half of their muscle mass. Not long ago, most people believed that this decline was inevitable. But in this day of computers, TV remotes, drive-throughs, and a generally automated lifestyle, most of the decline people experience is explained by the adage, “If you don’t use it, you lose it.”

Strength training is as essential to good physical health as aerobic exercise. Some of the benefits include:

. Reduced bone loss. Without exercise, bones can become porous and brittle. Strength training increases bone mineral density, making bones stronger and reducing the risk of osteoporosis.

. Reduced risk of injury. A proper training program develops balanced strength in all major muscle groups, and increases the strength of tendons and ligaments supporting the joints. This reduces the likelihood of falls and other accidents.

. Increased metabolism. Unlike fat, muscle is metabolically active tissue. As muscle mass increases, the number of calories burned also increases. Adding 3 pounds of muscle can boost daily calorie requirements by up to 15 percent. Even at rest, each pound of muscle requires an additional 45 calories per day. This helps you maintain a healthy body weight.

. Better quality of life. Strong muscles improve posture and balance, increase mobility and give you a body that performs well and looks younger than your chronological age.

Those new to strength training should consult a personal trainer or fitness professional to develop a balanced program and learn proper technique. The American College of Sports Medicine recommends two training sessions per week on nonconsecutive days to meet the minimum amount of exercise required to reap benefits. Each session should include eight to 10 exercises that target the major muscle groups in the chest, back, hips, legs, shoulders, arms and abdominals. For each exercise, do eight to 12 repetitions in a slow, controlled manner.

In order for muscles to increase in strength, they must be stressed with a workload that is beyond their present capacity. The key is to use a resistance that will bring the muscles to failure. This means that the muscles being worked are fatigued to the point that you cannot complete another repetition using correct form. To continue building strength, follow the 5 percent rule; once you can perform 12 repetitions of an exercise, increase the amount of resistance by approximately 5 percent. Working up to 12 repetitions with this increased weight will ensure a gradual, steady progression. You can use machines, free weights, resistance tubes, even your own body weight for strength training. Using a combination of methods provides exercise variety, reduces boredom and enhances your progress.

It is never too late to begin strength training. Muscular fitness is a critical component of a workout regimen which in turn should become a central part of your life. The stronger you keep your muscles, the better they will function and the longer you will be able to maintain your strength effectively and efficiently.

Be the best you can be, eat well, be active, stay strong and enjoy moving to improve.

Stephanie Peavey is the director of health and fitness at the Bangor-Brewer YWCA and is a member of the Move & Improve Coalition. For more information, contact coordinator Elanna Farnham.