Mobility / Stability Skeleton: The joint by joint approach

Looking at the joints in the body, every other joint is predominantly built for either mobility or stability. This is an important concept to understand when you are looking at the body as a whole.

All joints have the capacity of both stability and mobility. But each joints predominant function is either one or the other.

Predominately mobile joints are multidirectional and have lots of range of motion. They go in many different directions for example the hip joint does: Flexion, extension, adduction, abduction, internal rotation and external rotation.

Predominately stable joints have 2 main directions. For example the knee does flexion and extension really well.

If you lose mobility in a joint, another area in the body will have to pick up the slack. And same for if you lose stability in a stable joint, another area in the body will be forced to pick up the slack.

For mobile joint to be mobile and move well, it needs to base its movement off a stable joint. For example, the scapula needs to be stable for the gleno-humeral (GH) shoulder joint to be mobile. Looking at an example of putting your hair in a pony tail or scratching the back if your head, the GH joint can perform external rotation, abduction and extension as it’s supposed to. If the scapula is not stable, the GH joint then becomes stable in compensation for the scapula. This can results in the whole should complex becoming stiff and ‘stealing’ mobility from another are of the body. In this particular example, the movement tends to come from the low back, hips, t-spine and neck.

For a stable joint to be able to stabilize movement, it needs all the mobile areas to be able to perform their full range of motion. For example, when being over to tie up your shoes or pick something up off the ground, the lumbar spine needs to remain relatively stable to help the hip that is going into hip flexion. If the hip cannot get to end range hip flexion (lack of mobility), then the lumbar spine may help compensate by going into more flexion (lose some stability) to get those shoes tied up or item picked up off the ground.

If you would like to learn more, please visit the Feel Good: Movement page for upcoming classes.