Shoulder Impingement is a problem that results from everyday functional activities that require using the arm over the head. It is also common in sports activities where the overhead “throwing” motion is required. The tendons of the rotator cuff muscles get “pinched” between the proximal humerus and some part of the scapula. Although there are different classifications of impingement, in all cases resolution of symptoms requires the movement specialist to look for the “probable suspects” to determine the CAUSE of the problem. In previous blogs, the importance of the thoracic spine to shoulder function was addressed. This blog moves a little further along the chain reaction to “see” the role of the opposite side hip.
Appreciation of the role of the opposite side hip in rotator cuff impingement that is occurring during frontal plane shoulder abduction requires the application of the Applied Functional Science principle of LOAD TO EXPLODE. Whenever a human movement is executed (the EXPLODE), there first must be movement in the opposite direction (the LOAD). Very frequently the symptoms during the EXPLODE are caused by poor ability to LOAD somewhere along the kinetic chain.
Therefore the start of the search for the CAUSE requires looking at the joint motions that make up both the EXPLODE and the LOAD of shoulder abduction.
Shoulder Abduction (explode) of the Right Arm
Scapula Thoracic Spine Left Hip
Upward Rotation Lateral flexion to Left Abduction
Load for Shoulder Abduction (Shoulder Adduction)
Scapula Thoracic Spine Left Hip
Downward Rotation Lateral Flexion to Right Adduction
In this blog the focus is on the loading motion of the left (opposite) hip. Isolated assessment of passive and active motion of the left hip on a table does not provide the desired information. The ability of the left hip to LOAD into adduction and EXPLODE into abduction must be assessed during weight-bearing with all the parts of the Chain Reaction working together. The left hip must be driven into the motion of adduction. This lengthens and activates the hip abductors. The hip abductors decelerate the hip adduction and transform this LOAD into the EXPLODE required to propagate the kinetic forces up through the thoracic spine to the scapula.
The analysis movements of the 3D Movement Analysis and Performance System (3DMAPS) provide an effective and efficient method to determine if the left hip has the capability to successfully LOAD and EXPLODE. In this example, the Right Opposite Side Lateral Chain could indicate either a lack of hip adduction, or the inability of the hip abductor muscles to produce enough force. When the right foot crosses over to the left side with a lunge it “asks” the left hip to go into adduction. The swing of the arms to the right overhead also drives the left hip into adduction. Once the willingness of the hip to provide adduction is assessed (mobility), then the analysis shifts to determine if the motion can be controlled (stability).
In this example, let’s assume that the left hip demonstrated a deficit in either mobility or stability. Now the Performance System of 3DMAPS is utilized to increase mobility and train stability. These improved “resources” are then integrated into the LOAD TO EXPLODE movement using 3DMAPS frontal plane pivots. When the left hip is functioning properly, then movements adding load to increase strength with balance will be initiated. The foundational analysis movements are then tweaked to be more activity related or sport specific. The progression of the movements, based on successful pain-free execution, indicates to the client and the practitioner when it is time to return to function.