Understanding Movement: The Joint-By-Joint Theory
What is the Joint-By-Joint Theory?
The Joint-By-Joint Theory is a concept developed by Physical Therapist Gray Cook and Strength Coach Mike Boyle that describes the way in which different joint complexes act in relation to each other.
There are many different types of joints in the body that ultimately make up the skeletal system. For simplicity's sake, the Joint-By-Joint Theory categorizes each type of joint as being either mobile joints or stable joints.
A mobile joint is a joint that moves in more than one plane of motion. The planes of motion we are referring to are the sagittal plane (think forward bending and backward bending), transverse plane (thinking twisting movements), and coronal plane (think side bending).
For example, the shoulder joint (glenohumeral joint) is a ball-in-socket joint and can move through large ranges of motion and in multiple planes. You can lift your arm up straight in front of you, to the side of you, or behind you.
A stable joint is a joint that moves primarily in one plane of motion. Stable joints allow for some movement in other planes of motion, but their primary function takes place in one single plane.
For example, the knee primarily moves in the sagittal plane allowing for flexion and extension of the knee joint and is therefore a stable joint. Excessive motion in the other planes of motion can result in injuries like ACL or meniscus injuries.
Through observing and treating hundreds and hundreds of athletes, Cook and Boyle were able to learn the most common joint tendencies which often lead to injuries. By recognizing these joint behaviors they have categorized them accordingly and used this approach to improve movement patterns in their athletes.
Now this is not an absolute, end all be all. In reality, joint motion is a lot more complex and typically requires a balance between mobility and stability. However, this simple categorization helps to provide a lens in which we can view gross joint movements to identify patterns that might increase the risk of injury.
What Gray Cook and Mike Boyle observed is that these mobile and stable joints appear in an alternating fashion throughout the body. In other words, our bodies can be thought of as stacking mobile joints on top of stable joints.
Let’s start at the bottom of our lower extremity and work our way up to make sense of this concept.
Although the foot is made up of 26 different bones and 30 individual joints, the foot is considered altogether a stable joint. The foot is the base of the foundation that is the skeletal system and an excessive amount of movement in these joints would lead to an unstable base.
Next up, the ankle. The three joints that make up the ankle are mobile joints and designed to allow for movement in multiple planes to allow us to do things like walk, run, squat, etc.
Ascending the lower extremity, we find the knee. The knee primarily moves in the sagittal plane (flexion and extension) and while that range of motion is relatively large, this is a stable joint. We do not want excessive motion in the knee side-to-side or in a twisting manner… I’m sure you’re cringing just thinking about that!
Lastly, the hip joint. The hip joint, like the shoulder, is a ball-in-socket joint. We can move our hips in flexion, extension, adduction, abduction, left and right rotation which makes the hip a mobile joint.
Looking at the lower extremity you can see how each major group of joints falls into either the mobile or stable category and change depending on the functional requirements of that region.
Here is a more comprehensive list of which category each group of joints fall into:
Foot = Stable
Ankle = Mobile
Knee = Stable
Hip = Mobile
Lumbar spine = Stable
Thoracic spine = Mobile
Cervical = Stable
Scapula = Stabile
Shoulder = Mobile
Elbow = Stable
Wrist = Mobile
Hand = Stable
Why is the Joint-By-Joint Concept important?
As you can probably imagine, if joints in the mobile category become immobile and start to behave more like a stable joint, or vice versa, that can create some issues in the way we move.
If a mobile joint stiffens and lacks the mobility it requires to freely move through its range of motion, then the stable joints located directly above or below (or both) will begin to compensate for the lack of motion.
This is where the potential for injury creeps in. Compensatory patterns are a SHORT TERM fix and if left uncorrected can result in faulty movement patterns, uncoordinated muscular recruitment or activation, and, you guessed it, pain.
Injuries and joint dysfunction often present as pain in the joint above or below the dysfunctional region. This is why it is important to not only address the area where you are experiencing pain, but also check out how the surrounding joints and tissues are behaving to get a full picture of what is going on.
For example, you might be experiencing pain located at the knee, but the issue could actually be caused by lack of hip mobility or motor control.
This concept has gone on to change the way that athletes structure their training programs and how medical providers evaluate the quality of movement that their patients demonstrate.
The Joint-By-Joint Theory allows medical practitioners to identify what the breakdown in your movement patterns are and give you a movement diagnosis (ie. poor scapular stability) that helps to provide context to your medical diagnosis (ie. Impingement Syndrome of the Shoulder).
In many cases, focusing on improving the quality of a movement will result in a reduction in pain while improving overall function.
Think about the way you move as a whole. Just because you have pain in one place doesn’t mean that is where the problem is. By applying the joint-by-joint theory, we can identify and correct the altered patterns to help you get back to moving like you used to.
If you have any questions or think that you might be experiencing pain due to inadequate movement, schedule an appointment with one of the Momenta Doctors for an examination and movement screen to figure out the best plan of action for you.
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