Mobility vs Stability: The Building Blocks of Biomechanics

I think it’s pretty fair to say that we go through life with little awareness of whether parts of our body are mobile or stable, and thank goodness for that, how boring! (well, not for movements nerds)

It’s not until we experience a moment of instability that results in a stumble or a fall, or a period of pain that affects our life that we may even think about that concept at all.

Even as Movement Teachers, many don’t realize that the body actually has a very specific pattern of mobility and stability that behaves much like a game of Jenga. Each block, which in this case is a section of the body, is either mobile or stable, and then each block immediately above and below is the opposite depending on how we are moving at any given moment. This occurs from the head all the way down to the feet to ensure we remain upright and balanced.

This is one of my favorite ideas to teach fellow teachers as it really helps put all the pieces together in the biomechanical puzzle.

The ideal biomechanical pattern of mobility and stability is as follows:

However, most often our patterns are the exact opposite of the ideal that I’ve illustrated above. When one section changes its role, each block from top to bottom reverses its role as well, from mobile to stable or vice versa. Let’s explore what this looks like…

Does this look familiar? We all know someone that carries this pattern, probably lots of someones. Maybe you even recognize this in yourself.

To illustrate further, let’s distinguish between Stability and Mobility. By definition, these terms mean:

Stability – the ability to withstand force without being distorted, to be supported, to have strength, to be dependable, to be sturdy.

Mobility – not rigid, to move with ease without restriction, to be flexible.

Let’s be perfectly clear upfront though, stability does not mean stuck and immoveable either.

Going back to this little Mobility/Stability formula, if we think of this logically from a biomechanical perspective, our bodies do not function well with the same pattern in two adjacent sections (or blocks), whether mobile or stable. Imagine if your pelvis and your hips were both stable at the same time while you are trying to walk. You would walk like you were wearing a very tight skirt.

Here’s another example, the cervical and thoracic spines are not mobile at the same time in movement, when the cervical spine is mobile like when you look over your shoulder, the thoracic spine is stable by default until you get to the end of the cervical range then the rib cage follows to keep turning your upper body. They sort of follow each other versus moving at once. Try it.

The same applies to the knee and hip, or the hip and pelvis, and on it goes. In dynamic movement like walking, these changes from stability to mobility between adjacent joints occur in a split second so they are undetectable for the most part. But when the pattern is backward, you can imagine the confusion that occurs. Parts that are supposed to be mobile try to stabilize and parts that are supposed to be stable go rogue–what a mess!

The great news is that when we change the pattern in one section (or block), each subsequent block can change back to the ideal pattern. It’s like magic!

Try simply mobilizing your hip joint, and notice if your knee feels more stable or your low back feels more supported. Amazing changes can also happen throughout the body just by mobilizing the ankles or the ribcage. We hear this every day from our students after doing just one simple exercise.

Use this easy formula as you work with your students and watch how the quality and ease of their movement improve.

Interested in learning more valuable and applicable skills to help your students move better? Click HERE to check out the Body Harmonics Primary Specialist Certificate programs. All Movement Professionals are welcome.

Written by

Holly Wallis, Certified Movement & Rehabilitation Specialist, PMA®-NCPT
Director of US Operations, Body Harmonics Pilates & Movement Institute
Studio Director, ReActive Movement, 6200 LaSalle Ave, Oakland, CA 94611
510-710-5212