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Wear and Tear
Stop the Pain and Put the Spring Back in Your Body
By Bob Arnot Simon & Schuster
Copyright ©2004 Bob Arnot
All right reserved. ISBN: 0743225562
Excerpt
Chapter 1: Heel Pounders
Boom, boom, boom! Every night the sound of one jarring heel strike after the other bangs through the ceiling of our New York apartment. The noise makes it seem as if our upstairs neighbor is going to walk out on her husband for the last time. Ouch! The sudden, jarring sound is enough to wake the dead. So how do you politely tell your neighbor there's a problem? Try this.
Knock, knock, knock. BOB: Hi! I'm Bob. I live downstairs. I'm very concerned about your wife.
HUSBAND: Oh, really. What seems to be the problem?
BOB: You see, we can hear her pounding across the floor in your apartment. Of course we're not concerned about the noise, we barely notice it. But I am concerned about the damage she may be doing to herself.
HUSBAND: Huh? What damage?
BOB: Well, you see, she's a pounder.
HUSBAND: A pounder? What's that?
BOB: There are two different kinds of walkers, pounders and sliders. Your wife, just from the sound we hear, is a four-star pounder. When she walks, she digs her heels into the ground. Heel pounders are placing sharp, high loads on their knees. Over time thatcreates pain and over more time, may result in arthritis. I just thought you'd like to know. No use having your wife laid up.
HUSBAND: Gee, thanks.
BOB: No problem.
The conventional wisdom: A vigorous, heel-pounding stride is great exercise - and a good way to show you're in charge! The floor can easily be refinished.
The real deal: Don't worry about the floor; it's your joints you're killing.
REPETITIVE IMPULSE LOADING The American Podiatric Medical Association says the average person takes eight to ten thousand steps a day. Fast, hard loading of the joints without adequate shock absorption is at the heart of joint wear and tear. That's the theory of Dr. Eric Radin at Tufts University School of Medicine who believes that repetitive impulse loading, or RIL, is required to damage cartilage and bone. Dr. Radin states, "It's not the amount of force, but the speed with which
the load hits." Consider this analogy. Imagine driving fast over a bumpy dirt road with no suspension on your car. Every bump jars the frame and may damage your car or you! Slow the car down to a crawl, however, and even with the same heavy weight of the car's chassis on the frame, there's little damage because the speed of impact is reduced so drastically. It's the same with joints: slowly applied loads have little effect on the joint. Repeated rapid impulse loading, at the instant when your heel strikes the ground, produces joint damage. Why? Simply put, the very rapid application of load to the joint doesn't allow enough time for the muscles surrounding the joint or the joint tissues themselves to absorb the load. Be aware that the hard-and-fast landing is subtle and does not seem to enter the consciousness of most people.
On a scientific measuring device called a "force plate," this creates a very sharp spike. The rapidly applied force drives right through to your knees. Just think of it: with thousands of cycles a day and tens of millions cycles per year, you're damaging the joints and stiffening your tendons and muscles. You may well say, hey, no problem! That's what I've got cartilage for, to absorb the shock. Well, if that's the way you think, big problem! Contrary to popular opinion, cartilage and joint fluid have little shock-absorbing capacity. They're not good at attenuating peak loads.
As we'll see, well-controlled movement and strong, elastic muscles provide the best shock absorption.
Dr. Radin points out that you don't have to come down hard and fast, all you have to do is come down fast to create microdamage to the joints. The earliest detectable microdamage occurs in the bone underneath the joint cartilage in the form of microfractures.
Cheryl Riegger-Krugh, Sc.D., a physical therapist and associate professor at the University of Colorado Health Sciences Center, explains that bone is the fastest-adapting structure around a joint. The bone right under the joint cartilage adapts to this hard-and-fast loading by increasing in density. As a nice example, it's like playing basketball on a cement surface that does not give instead of on a wood surface that does. Playing basketball on a cement surface leads to more fatigue and soreness. Bone is able to adapt to the hard landings during gait from repetitive impulse loading. It can actually deform when it is loaded, and in deforming it provides a small amount of shock absorption. However, hardened, dense bone doesn't absorb the shock of landing during walking and thus the joint cartilage wears out as a result of pounding on the stiff bone underneath the cartilage. "The bone becomes much more rigid, and when it's more rigid, it doesn't give and the cartilage just keeps taking more and more of a beating because its underpinning isn't as resilient as it was," says Richard Ulin, M.D., clinical professor of orthopedics at Mount Sinai Hospital in New York City. Although the cartilage has no pain fibers, the bone has plenty, and the stiffened bone can cause real pain and disability.
If cartilage has little shock-absorbing capacity, what's the best way of absorbing shock? Well-coordinated, well-controlled muscle movement provides maximum active shock absorption. You'll find that as you learn well-coordinated, well-timed control of your limbs, you can significantly decrease, if not eliminate, pain and joint damage. Your muscles are your best shock absorbers. Learning to use them properly makes a world of difference.
The most recent research suggests that inappropriate loading may actually result in the production of molecules that signal the destruction of cartilage.
Dr. Riegger-Krugh asserts, "My own feeling is that the cause [of arthritis] is mechanical but the internal response in the body is biochemical."
MICROKLUTZINESS Let's continue with my neighbor. Not wanting to risk getting a punch in the nose, I made my exit without telling her husband what I really thought of his wife. She was a klutz. I mean, she had "microklutziness." What's microklutziness? The correct timing and placement of the foot on the ground minimize the impact of a fast heel strike. That requires extremely exact muscular control. If you lack just a slight bit of precision, if you're just a little sloppy, your joint is hit with a sudden, jarring force for which it is not prepared. We use the term "micro" because to the eye you don't look like a klutz at all! You've probably experienced acute pain if you misjudged the height of a step, stair, or curb you've stepped off of. The microklutz experiences those jarring forces with every step, though to a lesser degree.
How do you get microklutziness? Dr. Radin states that most microklutziness is inborn. In some people, the fine neurological control necessary for precise movement goes hand in hand with muscular strength. If you have suffered a slight loss of strength as a result of an injury, disuse, or age, you might develop microklutziness. You may also suffer a relative loss of strength if you have gained weight and not increased your strength. This loss of strength is particularly bad when the muscle is the quadriceps, the muscle at the front of the thigh, since that is a key muscle in controlling the knee. Dr. Radin points out, however, that almost all the muscles play a role in coordinated movement. He believes that the loss of muscle coordination causes an individual to become a pounder.
This idea has been borne out in studies of patients with knee pain. When you're in optimal walking form, your muscles efficiently control the rate of descent of the foot as it approaches the ground. In people with knee pain or poor coordination, the ground is used as a brake. Ouch! Studies have shown that people who suffer from knee pain don't flex their knees at precisely the right time to protect their joints as their feet strike the ground. Simply put, they load their joints more rapidly and absorb shock less effectively. During heel strike they pound into the ground instead of sliding along it. This lack of appropriate deceleration of the leg is linked to minor neuromuscular incoordination, or microklutziness.
This kind of movement doesn't cause just knee pain. The force may be transmitted to the hip, says Dr. Radin. He points out that the hip is a joint that frequently doesn't "fit" quite right. The hip "doesn't have washers and spacers in it like the knee joint. The knee can take a little error and still be all right. The hip is a high-risk joint, and slight anatomic changes can really kick up trouble as you get older."
THIS IS NOT YOUR GRANDFATHER'S DISEASE Okay, you may say, so I get arthritis when I'm eighty. So what? The sad fact is that microklutziness involves development of knee pain even in young adults. An ingenious study looked at the rate of loading on heel strike in a group of people who had the same walking cadence and speed. They found that those who already had knee pain hit the floor with a greater impact. The study concluded that "subjects with mild knee pain, possibly consistent with preosteoarthrosis, had a 37% higher loading rate of the vertical ground reaction force associated with heel strike." Quite simply, subjects with knee pain struck the ground faster and had a more violent follow through. Not only that, they absorbed shock less effectively, as evidenced by their landing with their knees straight and maintaining a straight knee after loading the forward foot while walking.
The most shocking aspect of the study was the subjects' age. They were in their twenties! Now is the time for them to make the change to prevent wear and tear, not when they're fifty or sixty years old and need a new knee joint! As we'll see, twenty-year-old basketball players already suffer thinning of the cartilage and changes in the underlying bone from the pounding they get while playing basketball.
While researching this book, I met hundreds of people, mostly women, who in their twenties and thirties already had knee pain from fast-and-hard heel strikes. Every one of them wore thin-soled, hard-heeled shoes and was a certifiable heel pounder!
SELF-TEST Here's how to find out if you are a pounder. A highly sophisticated gait laboratory can tell for sure, but you can gather some clues on your own. There are more than a hundred gait labs in the United States. Temple University School of Podiatric Medicine's Gait Study Center in Philadelphia, the Hospital for Special Surgery Motion Analysis Lab in New York City, and Massachusetts General Biomotion Laboratory are among the best labs in the country and can be the most helpful in locating a good gait lab near you.
• Do you walk loudly? Walk across a wooden floor barefoot. Do you or your family or friends hear your heels pound? Do your neighbors complain? Compare your foot strike to others'. Is yours the loudest? • Does your calf muscle jiggle on heel strike? Wear a pair of shorts during this test. Walk past a full-length mirror, such as one you might find in a health club. Walk with a forceful stride. Look to see if your calf muscle, also scientifically known as the gastrocnemius muscle, jiggles as you land. If you're a heel pounder, your calf will jiggle.
• Look at your shoes. Where are they worn? Do the heels wear down first? I found that mine do - right down to the sole! Do you have to replace your heels often? If your heels wear down very quickly, you may be a heel pounder.
• Do you walk straight-legged? Look at your stride in the mirror, say, on the wall in a gym or ballet studio. Is your knee straight when your heel hits the floor? Do you fail to bend your knee enough to absorb the shock? Do you put most of the shock impact on your bones rather than your muscles? Hold your thigh as you walk; feel how much your muscles contract normally, then try to flex your knee more. Feel the difference?
AT THE DOCTOR'S Doctors familiar with this problem will be able to diagnose troublesome flaws in your gait quickly and effectively. Your best bet is a hospital with a formal gait lab or at least with a force plate.
Physical therapists or podiatrists with training in identifying the clinical signs of repetitive impulse loading are a more cost-effective and feasible way of identifying this problem.
Be aware that your joints may not hurt. That's because when joint degeneration begins, you don't feel pain since joint cartilage doesn't have a nerve supply.
SOLUTIONS With osteoarthritis becoming an ever-greater problem among baby boomers, there needs to be more awareness of how to prevent it. Dr. Riegger-Krugh says, "It would be great if we could educate people to be aware of their movement and to let them know they can prevent this disease." Here are some simple steps you can take on your own.
1. Wear proper footwear. This is by far the easiest way to dampen the effect of heel pounding. Mario Lafortune, Ph.D., director of the Nike Sports Research Laboratory, says that virtually any kind of heel cushion will decrease the loading rate present at heel strike. See Chapter 8, "Fix the Flaws," for more on shoes. The right shoes can also help modify your gait.
2. Change your gait. Changing your gait can be a long and arduous process. Gait labs specialize in this; however, there are several simple suggestions to try before you invest in professional gait training.
• Keep your hips level. Use every opportunity to watch your hips when you pass a window or mirror. Do you see your hips bobbing up and down, or do they stay straight and level? You want to stay fairly straight and level so that there is less force on your heels as you land.
• Use your knees. Pounders have less maximum knee flexion and use their quadriceps for a shorter period of time after heel strike. Try to bend your knees more and use your quadriceps for a longer time to cushion your body weight as you land. If your knees are pretty much straight as you land, you're getting too little shock absorption out of your knees.
• Use your feet. Make a conscious effort to land on the outside of your foot and roll to the inside. This provides a substantial degree of shock absorption. The combination of proper knee and foot movement provides most of your shock absorption. In Chapter 3, "Fatal Flaws," we'll look at the different kinds of feet and how they are related to arthritis.
• Float when you walk. Make a conscious effort to walk as if you are on clouds and see if it decreases your pain! I have found that a combination of cushioned shoe inserts and shock-absorbing walking shoes go a long way toward helping you walk like this. Dr.
Continues...
Excerpted from Wear and Tear by Bob Arnot Copyright ©2004 by Bob Arnot. Excerpted by permission.
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