Proper mobilization of the body is not always what it seems. A summary of The Joint-By-Joint Approach; first noted by Mike Boyle and Gray Cook

“The body works in an alternating pattern of stable segments connected by mobile joints. If this pattern is altered, dysfunction and compensation will occur.” Gray Cook

Mobility is the amount of movement available at a joint or series of joints, and the ease with which the joint(s) can actively move through the range of motion (ROM). Mobility allows the body to get into positions needed to move in all three planes of motion and perform any given movement – without sacrificing stability! 

Stability is the ability of any system to remain unchanged or aligned in the presence of change or outside forces. Stability combines the qualities of timing, balance, strength, and muscular endurance to prevent any unwanted movement – without robbing from mobility! 

So in this movement philosophy, a mobile segment is designed to execute the movement in six degrees of freedom to achieve more positions within and around a joint. An example would be a ball and socket joint like the hip or multi-articular joints like the ankle. 

A stable segment would be a joint segment that moves primarily in one plane. For example, the knee is a primary flexor and extender. Therefore, it’s defined as a stable segment. Now even though the knee moves in all three planes of motion, it is still considered stable compared to the ankle or hip in this philosophy.

So here’s the typical pattern movement: 

  • Foot – Stable
  • Ankle – Mobile
  • Knee – Stable
  • Hip – Mobile 
  • Pelvis/Sacrum/Lumbar Spine – Stable
  • Thoracic Spine – Mobile 
  • Scapular – Thoracic – Stable 
  • Glenohumeral/Shoulder – Mobile 
  • Elbow – Stable 
  • Wrist – Mobile 
  • Cervical Spine – Stable 

You can see how this observation of an alternating pattern of mobility and stability can help describe how injuries occur. If you take the lower back as an example, you will often find that the hip joints and thoracic spine are limited in mobility. Therefore, the lumbar spine will sacrifice stability to gain more motion. This abnormal motion in the lumbar spine can be one of the main reasons for disc and facet injuries in the lower back. 

What can alter a typical pattern? 

The 4 T’s: 

  1. Traumas – Accidents, Posture, Repetitive Injuries
  2. Thoughts – Stress, Anxiety, Mental Collapse
  3. Toxins – What You Eat, What You Breath, What You Drink
  4. Technique – Poor Learned Skills, Muscles Patterns


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