The Stability-Mobility Principle

Gray Cook's joint-by-joint approach established a useful framework: the body alternates between mobile and stable segments, and dysfunction typically involves mobile joints losing mobility (and compensating through adjacent stable joints) or stable joints losing stability (and compensating through hypermobility). The clinical implication is that restoring mobility to a hypomobile joint without first ensuring adequate stability at adjacent segments can transfer the mechanical stress to the newly mobile joint in ways it cannot yet safely manage. Conversely, loading a hypermobile joint with stability exercises before restoring adequate mobility to the joints above and below it creates compensatory patterns that perpetuate rather than resolve the instability.

The principle that stability often precedes mobility reflects a simpler mechanism: if the neuromuscular system cannot control the range of motion currently available, adding more range increases the uncontrolled zone and the associated injury risk. A patient with SIJ instability, for example, who also has restricted hip flexion mobility presents with a dilemma: the hip mobility restriction may be a protective compensation (the nervous system reducing range to limit the uncontrolled zone around the SIJ). Aggressive hip flexibility work without addressing SIJ stability first may remove a protective compensation before the protective substitute (stability) is in place.

Clinical Application

The practical framework: assess active range of motion versus passive range of motion for the target joint. If passive range exceeds active range significantly (the joint has mobility but cannot control it actively), stability and motor control exercises are the priority. If passive and active range are both limited (genuine stiffness), mobility restoration is appropriate as the primary intervention. For most clinical presentations — particularly in patients with hypermobility, post-surgical joints, or acute injuries — stability precedes mobility. For post-immobilisation stiffness or structural restriction, mobility may precede stability work.

The exception: thoracic spine. The thoracic spine is one of the few regions where mobility consistently precedes stability work in clinical practice. Thoracic restriction is ubiquitous in desk-based and overhead-work populations and is rarely a protective compensation; it is almost always genuine articular hypomobility from disuse and postural loading. Restoring thoracic mobility first — before loading the thoracic extensors — allows the strengthening work to occur through the range that the mobilisation has restored, maximising its training effect.

Sequencing in Practice

A practical sequencing guide: (1) Identify whether the symptomatic joint has a mobility deficit or a stability deficit (or both). (2) If stability is deficient, address stabiliser activation before loading into range. (3) Introduce mobility work once basic stability is established. (4) Load through the newly available range with stability co-activation to integrate both qualities. (5) Progress to functional and sport-specific loading. This sequence produces more durable outcomes than addressing mobility and stability in isolation without integrating them under load.

References & Further Reading

  1. Cook G, et al. Movement: Functional Movement Systems. On Target Publications; 2010.
  2. Cholewicki J, McGill SM. Mechanical stability of the in vivo lumbar spine. Clin Biomech. 1996;11(1):1–15.
  3. Comerford MJ, Mottram SL. Functional stability re-training: principles and strategies. Man Ther. 2001;6(1):3–14.