Over the past few months, I have evaluated several clients who demonstrate difficulty engaging their middle trapezius, lower trapezius, and rhomboids. Thinking about their movement dysfunctions and how this impairment contributes to their pain and recreational limitations inspired this blog post. The purpose of this post is to explain common postural impairments that lead to weakening of the midback and loss of motor control in the corresponding muscle groups. I will also list tips to help correct the impairments, and provide guidance on steps you can take to seek consult if further assistance is needed.

We spend a large amount of time sitting, driving, texting, and working at the computer. Most people lack postural strength and knowledge of proper ergonomics and alignment, thus sit incorrectly for hours each day. The above activities draw the shoulders forward, subsequently protracting the scapula. Over time, the pectoralis minor will adaptively shorten, keeping the head of the humeral anterior in the glenoid (the socket of the joint). The scapula will sit in this protracted position and also anteriorly tilt from the tightness at the pectoralis minor. The rhomboids, middle trapezius, and lower trapezius will adaptively lengthen and weaken. The cross bridging action of the muscle contractile unit is inhibited, preventing the midback musculature from engaging.

As a person continues to sit with rounded shoulders and protracted scapulae, the tightness in the front of the chest and weakness in the midback will begin to flex the thoracic spine. This action with further protract the scapula and further limit the midback to engage. Over time, the mobility of the thoracic spine will decrease, making these impairments more permanent.

At this point, the structural consequences of prolonged sitting with incorrect posture can be recognized by the uneducated eye. The person is encouraged to sit up straight, pull their shoulders back etc. The trouble is, the person is unable to do it correctly. With attempts to correct posture, the long term shortening of the pectoralis and hypomobility of the thoracic spine will not immediately change. This person will compensate by hinging into their thoracolumbar junction in an attempt to stand up straight. They will engage the upper trapezius in attempts to engage the mid back that cannot contract due to its lengthened state fighting against tightness at the reciprocal muscle group. Over time, back pain/ neck pain/ radiating arm pain/ and shoulder pain can occur.

To properly try to resolve the above postural impairments, a person should first begin with a flexibility program to the pectoralis minor. It is essential during stretching to ensure that the person only feel the stretch through the chest and that they are not hinging into the lower back. A joint mobilization program to the thoracic spine should be implemented, again, being sure that the motion is being drawn by the correct joint spaces. Following mobility based exercises, active range of motion exercises (moving with gravity) should be performed to functionally carryover the achieve range. As one gets stronger, these exercises should be progressed to against gravity, then with resistance, then incorporated into static functional movement, then single plane dynamic movement, and eventually multiplane dynamic movement. Training of the transverse abdominus should complement the above exercises as well to help normalize spinal mechanics.

From the information above, you can see that it is not as simple as instructing a person who is slouched forward to sit up straight. This person is likely unable to perform the instructed task with proper muscle engagement and they may develop injuries from trying improperly.

For additional questions/ comments: contact Carla@redefinehealthandfitness.com.
This is a small part of the detriments of improper sitting, future posts will describe how the above postural impairments also link to dysfunction and pain in the lower body. Please consult with a physician, physical therapist, or qualified wellness professional before beginning a new exercise program.