In order for our arms to move they require a stabilizing base to anchor off. Lets consider the anatomy for a moment. The humerus (arm bone) connects into the glenoid of the scapula (shoulder blade). The shoulder blade’s only bony attachment is at the clavicle (collar bone). This single attachment is far from being sufficient to create a stable base. The remainder of the shoulder blade’s attachments to the body are through muscular connections at the spine and ribs. It is therefore necessary for the muscles to activate in a manner that allows both movement and stability to occur at the shoulder. In order for the muscles to achieve this they must be anchored to a relatively stable base.
If you consider the exercise examples provided above they all require two arms to move through a range of motion. Performing bilateral movements, specifically when the bilateral arm movements are performed in the same direction, results in a rigidity of the thoracic spine. So, although you may become physically stronger at maintaining the range of extension you already have, you will experience minimal improvements in range of extension or rotation by utilizing these exercise choices. You may also wear out your rotator cuff musculature as you constantly put them into end range and stress them against the glenoid, acromium and other structures. But hey, if you want to get injured go ahead!!!
When an exercise utilizes either a single arm moving or has the two arms moving in opposition of each other (cross crawl patterns for example) thoracic mobility can be enhanced.
A few examples will be illustrated below:
1) Squat with single arm over head reach
- I like this movement as it makes it very easy to identify side to side imbalances and lets you determine whether there is a greater issue on one side versus the other.
Video 1: Single Arm Overhead Squat
2) Single Arm Cable Rows
- the athlete must use the arm not holding the cable handle as aggressively as the hand that is holding the handle. This helps to insure rotation of the spine and allow flexion and extension to occur through the upper thoracic and costal (rib) region.
Video 2: Single Arm Cable Rows
3) Bear Crawls
- this exercise is a closed chain movement. It is my experience that shoulder imbalances correct much quicker when closed chain exercises are used. Closed chain means we are attached to a fixed surface and moving our body against this fixed surface. The opposite, or open chain movement, has our body acting as the fixed point and we move an external resistance around us. In a closed chain exercise the shoulder blade must anchor to the humerus and the thorax to the shoulder blade. IN an open chain exercise the shoulder blade must anchor to the thorax and then the humerus to the shoulder blade. This switch in how the activation pattern occurs is often a great way to “trick” the body into restoring normal movement patterns.
Video 3: Bear Crawls
4) Step Backs
- this single arm movement is an isometric exercise that allows for sustained ipsilateral thoracic extension, scapular retraction and glenohumeral external rotation. The step back increases the tension in the tubing which results in an increased load on the soft tissues (muscles). Instead of attempting to strengthen the cuff muscles by moving the shoulder thru actual rotation it is better to correct the scapula and thoracic positioning first.
Video 4: Step Backs
5) Kneeling Rotations
- this is a great exercise to increase the thoracic rotation flexion and extension on the moving side while working joint centration on the stabilizing side.
Video 5: Kneeling Thoracic Rotations
Obviously there are many other factors to consider including diaphragmatic breathing versus chest breathing, motor recruitment patterns, previous injury, etc but hopefully this will give you a bit of an appreciation on exercise prescription when attempting to improve thoracic mobility with your clients.
Future discussions will look into the effect of different breathing patterns on thoracic spine movement