There's more to exercised muscle than meets the eye. What I mean by that is in our body-image obsessed culture, some tend to focus on the superficial aspects of it, like looking buff and strong. But there are many more compelling health reasons to build muscle with strength training than how it looks under our skin.
Consider the obvious, and not so obvious, benefits:
Mobility - No muscle, no movement. That we can walk, dance, run, lift, pump, jump, kick is a miracle. The most advanced robot can only crudely mimic the incredible array of movements made possible by the interplay of our muscles and bones.
Protection - Muscles are our shock abosorber system. Whether your're an NFL football player or snow boarder or an old TOJ, the muscles buffer your bones and internal organs by dissipating the shock of a fall or blow. Muscles keep you from falling. The stronger and more resilient your muscles, the more protection you have.
Stability and Balance - We know where we are, and whether we're right side up, by a combination of the brain, nerves and muscles called proprioception. The muscles do the heavy lifting to keep us erect and in line with the forces of gravity, as well as the subtle adjustments to enable us to navigate uneven terrain, like rocky trails.
Bone and joint health - Muscle contractions move, and place force on the bones, which in turn strengthens them as they respond to the stress. The movement of the muscle also spreads the synovial fluid, a lubricant between bones in a joint, to help the bone surfaces work smoothly and painlessly.
Metabolism - The most over-looked function of muscle is its role in reducing inflammation, which has been associated with the killers like cancer, diabetes, and cardiovascular disease. A major cause of inflammation is insulin resistance, a condition in which the glucose in our blood (there from eating or drinking carbohydrates) has no place to go. Excess glucose causes the liver to convert it to fatty acids, which in turn increase artery-clogging LDL cholesterol.
However, here muscle comes to the rescue. Through a process called glycogenolysis, an exercised muscle will move the glycogen out of your blood and store it as a useful source of energy in the muscle itself. And depending on how intensely the muscle was exercised, this continues for hours, and even days, after exercising. Pretty cool.
We have over 600 of them, and they are mostly made of water. Tend them like a garden. Exercise them at least three times a week. Hydrate well and feed them with good food (mainly protein with some carbs). In exchange, they will take care of you, in more ways than you know.