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Stamford: Brain orchestrates movements to prevent us from falling

Editor’s note: The second part of this column inadvertently ran in the Nov. 3 Body Plus.

Falling is near the top of the list of fears reported among older folks. There are good reasons for this. One is that falls are common, and another is that when a fall occurs, it can have such severe consequences that the person cannot recover. This raises a question I get frequently: As an older person, is there anything I can do to improve my balance? The answer is yes. Here’s why.

Standing upright and moving around efficiently are skills that are underestimated and taken for granted, because they come so easily and naturally to us once we learn how to do them at a very young age. They may come easily and naturally, but they require a remarkable coordination of the body’s nervous and muscular systems.

To function properly, the brain must have adequate information. It receives feedback about what all parts of the body are doing at any given moment from sensitive nerve endings that send the brain reports constantly.

The brain uses this information to make sure the muscles contract in exactly the right sequence to produce what is needed, moment by moment. This is called coordination. If something intervenes to disrupt coordination, and if the body cannot respond instantly, you likely will fall. Let’s examine a common example.

You are walking along paying no attention to the sidewalk, because you assume it’s flat and smooth and won’t interfere with your walking. Then, suddenly, there is tiny rise in a concrete seam that catches the toes of your right foot as you move it forward. This throws everything out of whack, because it’s unexpected and contrary to what has been ongoing during your walk.

Immediately, your brain is informed of the mishap – your right foot is expected to be out in front of you to absorb the transfer of weight from the left foot as it pushes off. However, the brain is told that the right foot won’t be where it’s supposed to be.

Emergency! Now the brain has to scramble to prevent a disaster. Instantly, new signals are generated and sent by the nerves to the muscles to override the original signals that no longer can be carried out. The leg muscles are called into action in a different way, and you must cope with your body weight falling forward. The right foot must recover, be raised, change its position and be thrust forward as fast as possible, in time to land and absorb the impact of your falling weight.

This reaction won’t be a coordinated effort, but that’s not what’s important. Staying upright and getting the right foot out there any way you can is what counts. The right foot lands, but not perfectly, which creates a new need to react and make additional adjustments.

All of this action must take place instantly, and that’s the problem. As we get older, our ability to react (reaction time) slows. This is a natural consequence of aging, as is a decline in just about every other physiologic function, including muscular strength and stamina. But the rate of decline differs from person to person. Some of this is genetic, but much of it is based on how much effort you invest to preserve your abilities.

What’s more, reaction time is intertwined with muscular strength. You may react effectively. You may, in other words, respond perfectly to the rise in the sidewalk and get your right foot out there in time. But if the muscles of the right leg are not strong, the sudden demand from your body weight falling forward may be overwhelming, and you will fall.

As if this isn’t enough to be concerned about, it’s possible that you may be able to respond perfectly and your muscles are strong enough to keep you upright, but you fall anyway. This may be caused by an inability of the brain to orchestrate what needs to be done in a timely fashion.

Bryant Stamford is professor and chairman of the department of exercise science at Hanover (Ind.) College. Address questions or suggestions to “The Body Shop,” The Courier-Journal, P.O. Box 740031, Louisville, KY 40201

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