People often ask me about exercise without using weights and weight machines.  What exactly is weight bearing exercise?

The bones in the human body are as alive as any other tissues.  Bone is laid down in the same direction as mechanical stress.  In other words, as you use your body, your skeletal frame, your bones build, and become more dense.  Just like muscles, if you don’t use them, they will weaken.

In fact, interestingly enough, this is a big problem for astronauts.  When they are exposed to the weightless environment of outer space, their bones actually shrink up to 2% per month, and they return brittle and weak.  They actually develop Osteoporosis over a very short period of time.

Why do I mention astronauts?  Well because people that are bedridden because of an injury, or just people who don’t exercise much, tending more towards the sedentary lifestyle, exhibit these same symptoms of Osteoporosis, albeit over many years.

So weight bearing exercise, opposing the force of gravity, is an important part of your fitness routine, be it running, rowing, or lifting some weights.   My personal favorites are body weight exercises, that use only the weight of the body to stimulate and build muscle and bone.

In researching for this article, I found a very good piece on the subject What’s G Got To Do With It?  You can all search google for terms like “astronaut osteoperosis”, “astronaut bone mass”, “exercise bone density”, etc.