I've overheard and been a part of conversations where, in the context of x-ray findings of osteoarthritis, patients and health professionals alike attempt to draw the conclusion that what they're seeing on the x-ray is a direct effect of physical punishment the patient had endured over their lifetime.
"You've put your body through hell."
- Have you?
"That's the price of competing at your level of competition."
- Is it?
"Is this because I fell off my bike when I was a kid?"
"Your hip has seen better days"
When terms like "degeneration", "breakdown", and "destruction" are used to describe the process of osteoarthritis, we immediately attribute it to physical stressors such as the not-so-smart activities we've done as kids or the sports we've played.
But here's the thing - your joints are not like your winter tires. It's simple to draw the conclusion that the amount of time you use your winter tires is highly correlated with your tire treads wearing down. The same can't necessarily be said regarding your joints. It is much more complicated than that. Before anyone gets bent out of shape regarding this statement, I will add there are obvious caveats to that statement.
Yes, excessive demand on any joint in the body can cause some degree of degeneration over one's life. BUT, it is much more likely that a joint could see degeneration of far greater severity when it is coupled with physical demand and dysfunction (see "The Four Pillars of Dysfunction" post). If a joint isn't doing its job, then a joint (or joints) above or below it will compensate in order to achieve whatever your goal is. That could anything from deadlifting several hundred pounds, to picking up the daily newspaper. When a joint sees excessive force due to dysfunction somewhere else, it can lead to arthritic changes because the integrity of the joint is compromised due to one or any combination of shearing, compression, or torque forces on the joint.
Everything I've mentioned so far really only addresses one part of this joint degeneration conundrum. I simplistically like to think of the development of osteoarthritis having a curve similar to what is shown below.
There are several types of joints in the human body, but generally speaking joints are made of up two bones connecting together through a bridge of connective tissue called a capsule. Between these bones we have cartilage that is bathed in fluid which provides oxygen and nutrients to the cartilage. The fluid is ultimately there to keep the cartilage healthy and to lubricate the joints, since most joints don't have the greatest blood supply. The key is to keep this fluid moving so that the cartilage can reap the rewards of this nutrient and oxygen rich fluid.
When we don't move our body, the integrity of the joints are negatively affected because they are essentially starved of oxygen and nutrients which causes the cartilage to break down. In this sense, movement is medicine since it can favorably affect the health of the joint. Of course there is a plethora of other health benefits extending beyond joint health that you can receive through movement/exercise.
So what's the deal? I just said both movement and lack thereof can cause degeneration. Should you exercise or should you not? This is a loaded question, but simplistically the answer is YES. Movement without dysfunction trumps both lack of movement and movement with dysfunction. There are health professionals (chiropractors, physiotherapists, etc.) out there trained to determine the integrity of your joints through various assessment systems and tools. They can screen your movement abilities in an effort to determine if you'd be putting yourself at risk of injury with recreational and competitive activities. There are ways to address any dysfunctions you may have in safe yet challenging ways so you may put less "wear and tear" on your joints down the road.