A Simple Explanation On How Your Joints Work
Optimal biomechanics refer to the joint positions and muscle activations that are universally correct across all movements. Before we go in depth on the specific positions and activations, let’s discuss a more general framework of how these joints and muscles work.
The joint-by-joint rule was originally created by genius practitioners Gray Cook and Mike Boyle. This approach to movement views the body as a series of interconnected joints, starting low with the ankles and ending high with the cervical spine.
Next, each of these joints has one of two specific functions: stability or mobility. Stable joints are optimized when maintaining their position or undergoing controlled movements. Mobile joints, on the other hand, are optimal for performing large, forceful movements with higher ranges of motion. As a gross oversimplification, you can just think that mobile joints like to move and stable joints don’t. These two joint functions alternate joint-by-joint from the bottom to the top.
That’s our general framework for biomechanics. Some joints like to move, some joints don’t, but why does it matter? Well, the thing is, all of these joints are interconnected and affect one another. When one joint loses the ability to perform its function, the joints around it compensate to help out. For example, if the hips get tight and lose their mobility, the neighboring lumbar spine and knees will step in and provide some range of motion. Therein lies the problem. When stable joints compensate and create mobility they wear down, eventually causing pain and injury.
Look at the most common sites for injury: the knees, lower back, shoulders, and neck. Notice anything? They’re all stable joints! One of the highest impacting factors in musculoskeletal pain is dysfunctional stability-mobility joint relationships. As such, our framework for general biomechanics begins with understanding each joint’s role as either stable or mobile, and then applying the proper mechanics to fulfill those functions.