What is physical strength?
Wikipedia defines physical strength as the “…exertion of force on physical objects” in order to lift, pull, or push them. In our everyday lives we lift boxes, pull open doors, push a grocery cart, and execute a variety of other actions.
As if by magic, our brain sends signals to our muscles that are attached by tendons to the bones in our head, neck, arms, hands, legs, and feet to contract or relax in patterns that allow us to execute a myriad of complex movements: walk, shuffle, side-step, jog, stop, pivot, reach, bend, catch our balance…a symphony of movements that carry us through our daily tasks.
…and why are our muscles so darn important?
Skeletal muscles—those attached to our bones—account for the vast majority of the muscle mass in our body. (The other types of muscle are “cardiac” muscle—the heart—and “smooth” muscles—that are found in the walls of our hollow organs, the walls of the circulatory system, and in other parts of our body.)
Skeletal muscles permit movement and functionality for our day-to-day activities. And strong muscles facilitate greater vigor and more confident movement.
How do our skeletal muscles work?
In order for our muscles to contract, they require energy. The source of that energy is called ATP (adenosine triphosphate). ATP is created from the food we eat, which provides protein, carbohydrates, and fats.
THE FED STATE - When we are healthy and well fed, amino acids (from protein sources), glucose (from carbohydrates), and lipids (from fats) pass from our circulatory system to the brain, kidneys, muscles, liver, and adipose tissue in support of the normal functioning of our body’s muscles, skeletal joints, and other organs.
THE FASTED STATE -When food sources of energy are decreased or depleted (when we are in a “fasted state”), metabolism for maintenance of normal bodily functions depends on the transfer of energy resources (amino acids and glucose) stored mainly in the liver and skeletal muscle.
This is all normal. So far, so good.
What can go wrong?
If illness or disease attacks our body or we fall into a malnourished state, amino acids are converted into glycogen (stored glucose) for energy, and are drawn directly from skeletal muscle to meet our metabolic needs.
These abnormal conditions can have serious consequences.
Depletion of the energy sources stored in the skeletal muscle can lead to:
A natural form of muscle loss—Sarcopenia
There is also a natural form of loss of muscle mass called sarcopenia. Sarcopenia is the gradual loss of muscle mass and function that occurs with aging or the lack of use. Beginning as early as our 40s, our skeletal muscle tissue and strength begin to diminish in a linear fashion. By our 80s, up to one-half of muscle mass may have been lost.
See the change from figure A to B on the left below.
This process can lead to loss of function, disability, and frailty.
In addition, not only do muscles lose mass, they are also subject to fat infiltration (see the change in the figure on the right). As our metabolism slows with advancing age, glucose from our food is processed less efficiently, and more of what we eat is stored as fat.
We must actively, intentionally, use our muscles in order to counter (and reverse!) the effects of sarcopenia. This is part of striving to achieve health and wellbeing so that we can thrive and not merely survive.
Randall Lightbown is the founder, head coach and face of S+.
A certified strength training specialist, nutrition coach, martial arts adept and certified masso-kinesitherapist, Randall combines his expertise in the movement arts with a deep understanding of the human body. He dedicates his life to helping people of all ages achieve health and wellness and realize their greatest potential for healthy living, satisfaction and personal fulfillment.
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