Whenever I talk to patients about their posture and that their injury or symptoms are in large part due to poor posture I always get an odd look. It’s one of surprise and as if to say “My mom told me to stand up straight, why am I paying you to hear this?” or “This has got to be more complicated than this.” I then take the time to explain how this can be.
I think everyone can understand the concept of stress and strain. Really, that’s all I do. I deal with stresses and strains. There are a couple of variables that we all deal with: load and time. How much load are you carrying and for how long. Depending on how you carry the load and for how long will predict how much stress or strain you will place on a structure or in this case a joint.
First we need to understand the principle of loads on joints. Joints hold up best if the load, a person’s weight, is spread evenly across them. It’s the scenario of the man who lies on a bed of nails. If he lies down on thousands of nails each nail only has to carry a small amount and therefore none puncture the skin. If he lies down on only one nail the load is too great and it punctures the skin. Another example is that of tires. If tires are properly inflated and aligned they make full contact with the road and will last much longer than if not. The problem is twofold. When loads are not evenly distributed they not only apply more pressure at that one point to wear the joint uneven they wear it down faster.
Our job when we get out of bed in the morning is to stay upright. Even when sitting we have to hold our trunk up against gravity. Joints are designed to take the impact of movement. As soon as the foot hits the ground a force is directed up. Newton’s law: for every action there is an equal and opposite reaction. When we stand up or start to walk the weight of our body is hitting the floor and therefore this same force is coming back to hit us. We have to do something with this force so it does not damage our structures (joints). When bones are properly aligned they share the load so no one joint is taking it all. (one nail vs many nails example). When standing or sitting there is little movement so the action is uncomplicated but nonetheless loads are being distributed. Let’s take a look at a few pictures:

As you can see in these pictures of the spine that load is not equally distributed. What the pictures don’t show are how the spine can get that way. In some cases there are deformities at the spine level that shift things but most often problems come from the foot up. In subsequent posts we will look at the foot and move up to see what postures may be caused by such deformities and then look at possible problems that arise as well as solutions for these