This is a follow up to last week’s post on core stabilization. In that post, we went over what exactly is meant when we refer to our “core muscles”, and how we can use these muscles to stabilize our movements. In today’s follow up we will briefly go into bit more detail regarding what is meant by the term “stability” in reference to our bodies as we shed a little more light on the concepts presented last week.
Stability in body movement
“Stability” is a term often used in the fitness and rehabilitation world. You will frequently hear terms such as “Sacroiliac joint instability”, “shoulder instability” or “low back instability”. While these terms are commonly used to diagnose a variety of aches and pains, the exact meaning of “stability”—and what it means for a region of the body to be unstable—is often poorly understood.
“Stability” can be easily thought of as an increase in stiffness. A useful definition of stiffness is the amount of force required to deform a muscle—more force required means greater stiffness. This stiffness is need by our bodies to support load, to transfer kinetic forces through different regions of the body, and to move our limbs in a controlled, coordinated manner. Therefore, an area of the body designated as “unstable” is an area of the body that displays difficulty providing the required stiffness to support a given movement. A great way to visualize this is to steal a concept from the author of the book Facial Trains, Tom Myers: think of the human body—and its facial (connective tissue) network—similar to a “tensegrity model.” Each individual segment of a physical system is supported by, and must in turn, support every other segment. If you apply a force to any part of the model, the entire model will deform in response to that force. This is exactly how our bodies absorb and distribute forces. Varying the stiffness of muscles over various regions of the body serves to control and distribute forces moving through the body to allow for powerful, coordinated, and controlled movements.
Consequently, the stability patterns that our bodies develop—both static and dynamic—result in our individualized posture and movement strategies as we respond and adapt to the unique stresses life throws our way.