Age-Defying Fitness: Keeping Up Your Strength

Summarized by Robert W. Griffith, MD
April 19, 2007

Marilyn Moffat and Carole Lewis are physical therapists who have been in private practice for a number of years. They have both published and lectured extensively, and have written "Age-Defying Fitness" based on their experience with their aging patients. Their aim is to inspire and motivate readers to do something good and long-lasting for themselves: exercise. We are pleased to post several extracts from their book. Here is the second. Robert Griffith, Editor.

Strength

"The older you get, the stronger the wind gets, and it's always in your face."
Jack Nicklaus

Strength is a key component of healthy physical performance; strong muscles help you move easily and enjoy life. And unlike many other things in life, muscles respond to stress in a positive way. They get stronger. Strength training is a safe and effective way to improve muscle capabilities and to increase healthy physical perform¬ance. Good programs do much more than add bulk - they help to sculpt and stabilize the body. You can gain strength and muscle size throughout your life. It is never too late to start.

Proper Strength

Strength is a muscle's ability to produce force or do work, such as lift a weight or climb a stair. Generally, the larger the muscle, the greater its ability to produce force. For example, the large muscles of the buttocks and the fronts of the thighs are naturally stronger than those in the forearm or the eye. Muscles develop the most between birth and ado¬lescence and generally peak in strength in the thirties, but with regular strength training, they can continue to perform at increasing levels despite advancing age.

Diane, 54, didn't think of herself as old and weak while working at her bank job or performing her weekly chores, including grocery shopping and rolling out the trash-can on pickup day. But when her eagerly-awaited first grandchild was born, and within 6 months weighed 20 pounds, she found herself huffing and puffing after a few minutes of carrying the infant.

Strength Changes

Muscle contraction allows action to take place. The action can be large (swinging a golf club), small (blinking), or static (standing still). As you age, your muscles tend to lose their ability to contract at a strong and effi¬cient level. Atrophy (a reduction in muscle size) also occurs and may lead to decreased range of motion and loss of muscle bulk, particularly in the forearms, hands, lower legs, and feet. Between the ages of 30 and 80, most people experience a decline in physical strength of approximately 30%. Everyone has to do more to maintain and increase strength as they get older.

Strength loss associated with aging usually occurs almost imperceptibly and often goes unnoticed until normal activities - such as walking upstairs, carrying groceries, or picking up a grandchild - become arduous. All too often, when these tasks become more difficult, you do less. Decreased activity means your muscles are taxed less, and - somewhat perversely - your body adjusts to a lower level of activity. The result is that you gradually become weaker. But it doesn't have to be that way.

The truth is, no one at any age can take strength for granted. Whether you're moving from your late twenties to early thirties or from your sixties to your seventies, it's important to do a little more each day to avoid gen¬eralized weakness. With training, your muscles can continue to serve you well, even increasing in strength despite advancing age. In our offices we see many people who mistakenly believe that there is nothing they can do to get stronger as they get older; they believe that they just have to learn to live with being weaker. Not so! Research offers numerous examples of people from 40 to 100 years of age who - on a prescribed and monitored individual exercise program much like the one in this chapter - experi¬ence tremendous increases in strength. We delight in telling our clients and patients about a study that included only men and women over 90; after 6 weeks on an exercise plan, they achieved an almost 200% increase in strength.

Muscles

Muscles are the power behind movement. Attached to bones, usually by tendons, they contract in 3 ways-by shortening (bending your elbow to look at your watch), by maintaining consistent tension without movement (keeping your head upright), or by lengthening (walking down stairs).

Approximately 100 different muscles are found within the body in 3 major classifications: smooth, cardiac, and skeletal. Smooth muscles, over which you have no voluntary control, are found primarily within the internal organs (blood vessels walls, digestive tract, bladder). Cardiac muscle is also involuntary. This specialized type of muscle enables your heart to beat and pump blood throughout your body.

Skeletal muscles are the only ones over which you have conscious control; they enable you to move your body. These are the mus¬cles on which you concentrate in order to increase your strength.

Skeletal muscles affect all types of movement, including flexion, extension, abduction, adduction, and rotation. Flexion is the bending of a body part: your knees to squat or your elbow to bring food to your mouth. The opposite of flexion is extension or the straightening of a body part, such as your knees to stand or your elbow to lower your hand to your side. Abduction is movement away from the middle of the body: pushing your leg or raising your arm to the side. The opposite of abduction is adduction, or movement toward the middle of the body: crossing one leg over the other or bringing your right arm to your left shoulder. Rotation is movement around a pivot: turning the palm of your hand up and down or turning your head side to side.

Skeletal muscles act in opposing groups so that if one muscle or group of muscles contracts, the opposing muscle or group relaxes. In other words, if you bend your knee (using your hamstrings), the opposing muscle group (your quadriceps) will relax.

Skeletal muscles are composed of two types of fibers. Type I, called slow-twitch fibers, enhance endurance, helping to sustain muscle activity over long periods of time. They are best trained with a high number of repeti¬tions and low weight. Type II, or fast-twitch fibers, enable rapid move¬ment for performing quick, short bursts of activity and should be trained with fewer repetitions and heavier weights. Abdominal muscles are almost exclusively made up of Type I fibers, so to strengthen them, you should perform many repetitions of a partial sit up, using no or very low weights. Thigh muscles are composed mostly of Type II fibers, so to strengthen them, you would use heavier weights and fewer repetitions.

The three major types of muscle contractions are isometric, isotonic, and eccentric. An isometric contraction occurs when a muscle contracts and produces force but no movement. When you press your palms together, the muscles of your arms and chest are contracting even though your hands aren't moving. An isotonic contraction causes movement through an arc of motion, such as lifting your leg as you climb a step or raising your knee toward your chest when you sit down. An eccentric contraction occurs when a muscle acts as a brake to control weight as the muscle is lengthened. When you squat slowly, your front thigh muscles perform eccentric contractions. Eccentric contractions may be associated with muscle soreness.

This chapter in the book goes on to sections on self-assessment of strength, practical tips for strength exercises, and 8 exercises each for the arms, legs, and trunk, all with explanatory photos.

Future extracts from "Age-Defying Fitness" will cover flexibility, balance, and endurance.

You can buy "Age-Defying Fitness" from Amazon or from Peachtree Publishers.

Source

• Age-Defying Fitness: Making the most of your body for the rest of your life. M. Moffat, CB. Lewis, 1st edition. Peachtree Publishers, Atlanta, 2006

Related Links
Amazon: Age-Defying Fitness
Strength Training for Older Adults - What to Expect
Lifting Weights May Boost Heart Health

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