Julius Wolff was a German Anatomist and Surgeon who discovered that bones build and rebuild depending on the types and amounts of weight placed up on them. It was this discovery that lead us to understand how it is that exercise increases bone density. This is especially important to those concerned with or suffering from osteoporosis or degenerative joint disease.
Your bones have multiple parts. If you’ve ever looked at a bone in a steak or out in the wild, you might have noticed there to be a smooth shell on the outer part. You might have also noticed that there was a kind of “web-looking” inner part as well. The outer part is called the “Cortex” and the layer beneath it is called the ” trabeculae“; which actually means comes from the Latin word for “bar” or “beam”. That’s apropos since it acts as scaffolding; creating the framing of the structure resulting your ability to maintain form against gravity.
When bones are stressed, they build trabeculae in direct resistance to that stress. When bone is not stressed, bone reabsorbs that trabeculae and loses it’s density. We see this at work in Tennis players. The bones in their racket-holding wrists are more dense due to the repetitive vibrations of hitting a tennis ball over and over. Martial Artists who regularly break boards with their elbows, develop denser bones right where they strike their target. We also know that because astronauts are under a fraction of the stress due to the lack in gravity, they often return with a greatly diminished bone density. Their bones have begun to lose their trabeculae because there is very little stress placed up on them in space.
Now, other factors play into bone density other than mechanical stress. Your body’s ability to take Calcium from your diet and place into bone also depends on things like Stress Level, Vitamin D levels, Blood pH and to some extent, genetics.
I see the results of what is now called “Wolff’s Law” in my office every day. You see, when a spine is not aligned correctly, your body begins to build bone where it needs to be, in order to deal with the change in force on the joint. When it does this due to inordinate stress on a joint, we call these bone formations, osteophytes or “spurs”. The most come place you hear about these is in a heel “spur”.
When forces on bones and joints are not even, degenerative disc and joint disease, along with osteophytes and spurs are almost inevitable, and unfortunately ubiquitous.
Make sure your body is properly aligned, you exercise more days than not and maintain a diet high in fruits, vegetables and lean meats. Also, check your Vitamin D levels regularly to ensure your bones are “Under Construction” like the Tennis Player and not “Under Demolition” like the astronaut.