Muscle Medicine: The Revolutionary Approach to Maintaining, Strengthening, and Repairing Your Muscles and Joints Read Free Page B

of specific chemicals that activate the muscles. What happens is this: the brain sends a chemical message to the motor neurons in the spinal cord which then deliver that message to the target muscle, telling it what to do. Sensory nerves gather information about the current status of that part of the body and send that information back up the spinal cord to the brain for processing. Some information is so basic, it doesn’t need to be processed by the brain: it travels only from the muscles to the spinal cord and back, in a feedback loop called a “reflex arc.” For example, the muscles have reflexes that prevent them from overstretching or overcontracting, or that jerk your hand off a hot stove before you even register pain.
    A more complex conversation between the muscles, nerves, and brain is called “proprioception”—knowing where your body is in space. It allows you to run and jump and navigate the world without falling (usually) or even thinking much about it. When you’re injured, that conversation is disrupted. Not only do the muscle tissues have to heal, but the lines of communication between the muscle and the brain have to be reestablished so you can run or swing a golf club or play a note on the violin with your brain on “automatic pilot.”
    But it’s how muscles interact with each other and the rest of the body that most concerns us here. Muscle is dense with capillaries that feed it with the blood— carrying oxygen and nutrients—that it needs to do its work. We may think of the football player with big muscles as rugged and tough, but the muscle tissue itself is surprisingly delicate, made up mostly of water. (They don’t call it soft tissue for nothing.) The body is closely packed with overlapping muscles that must move smoothly against each other if humans are to move with any fluidity.
    From micro to macro, the master plan is steady, unimpeded motion—movementis life. Not only do neighboring muscles need to slide against each other, so do the fiber bundles inside the individual muscles, and so again, the tiny myofibrils inside the fibers. We can see what muscular contraction looks like at the most basic molecular level only with an electron microscope: two types of protein filaments inside the myofibrils, actin and myosin, pulling against each other.

    The defining aspect of the muscle is the muscle “belly,” where most of the muscular force is generated. Fortunately, nature has outfitted the muscle with tough connective tissue at both ends, the tendons, where the muscle attaches to the bone. The tendons transmit muscular force and actually pull on the bones. Remember, regular muscle tissue can’t even hold a surgeon’s stitch, much less control a bone in motion. (Our word muscle comes from the Latin word for mouse, mus . The cord- or band-shaped tendons were thought to resemble the snout and the tail of a mouse!)
    Another element of the muscle package is the fascia, the thin, tough, translucent membrane that weaves around everything in the body: muscles, bones, organs, nerves, the works. You could visualize it as the casing around the meat in a string of sausages. Or take a close look at an uncooked chicken or slab of beef. It’s the white covering around the muscle that runs through it and around it. In the body (human, cow, or chicken), fascia serves as a kind of flexible internal skeleton, holding the muscles in place, but also moving with them, and helping them slide over neighboring structures.
    BONES
    You take for granted that your muscles are a living, dynamic system. Work out in the gym even for just a few weeks and you’ll see the strength and, depending on the amount of testosterone circulating in your system, the size of your muscles increase. (Inside the muscles, the numbers of capillaries increase, pumping upthe fluid content; new protein—the building block of muscle—is laid down; the mitochondria—the power plants inside the cells—increase in density.)
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