By MARTY MILLER, ATC, DHSC, NASM-CPT, CES, PES, MASTER INSTRUCTOR
Human movement is an amazing orchestra of muscle contractions controlled by the central nervous system to create joint actions to accomplish specific tasks. The motor tasks can be as simple as raising a glass of water or as dynamic as an explosive golf swing.
When you look at all the muscle and joint actions the body is capable of, there are countless movement patterns that can be created. In order to allow the body to have such a vast amount of movement possibilities, the 10 main joints (listed below) of the human movement system (HMS) have specific roles and responsibilities. Starting from the ground up the joints are:
- Foot
- Ankle
- Knee
- Hip
- Lumbar Spine
- Thoracic Spine
- Cervical Spine
- Shoulder
- Elbow
- Wrist
When evaluating the HMS, these joints can be categorized as either a stability- or mobility-based joint.
Mobility: The ability to move freely and easily.
Stability: The ability of the body to maintain postural equilibrium and support joints during movement.
When the joints are looked at individually, each joint can be classified by their main responsibility. Of course, every joint will have some overlap in roles, but each has a primary function. The stability joints are the foot, knee, lumbar spine, cervical spine and elbow. The mobility joints are the ankle, hip, thoracic spine, shoulder and wrist. A clear pattern emerges in that the kinetic chain is a series of joints stacked on top of each other in an alternating pattern of stability then mobility. This sequence creates the ideal platform for dynamic human movement.
Unfortunately, a disruption in this pattern can occur, creating movement dysfunctions. The most common causes of this alternating pattern disruption include previous injury, chronic pattern overload, muscle imbalances or bony malalignments. When issues like this occur, it can affect the normal function of the joint. If the dysfunction is severe enough, the joint, or in many cases joints, will then begin to lose the ability to maintain their primary stability or mobility function. Quite often the joints that are stability-based become more mobile, and the joints that are mobility-based become more stable.
When the joints within the kinetic chain lose their primary role due to dysfunction and change roles, human movement becomes compromised and the chance of injury increases significantly. Fitness professionals who understand how to properly assess human movement, understand the function of each joint, create programs that either restore or ensure human movement will not be compromised, are at an enormous advantage to help their clients move better.