What yoga postures stabilize the shoulder blade by engaging serratus anterior and the trapezius muscles?
Research Study At A Glance
The Research Question Asked
Can we use yoga postures to stabilize the shoulder blade and potentially reduce shoulder pain?
Type of Study
Controlled, cross-sectional study conducted under laboratory conditions
Study Participants (Sample)
Sample size: 20 participants
Study participants:
- age 18-40
- female
- healthy shoulder function
- had some yoga experience
Methods
Surface electromyography (EMG) was used to measure muscle activity of lower, middle, and upper trapezius and serratus anterior (the main muscles used in scapular stabilization).
Results
Most yoga postures that were evaluated generated more muscle activity from serratus anterior than from trapezius. Locust pose with arms forward generated the greatest muscle activity from trapezius, and crow pose generated the greatest activity from serratus anterior.
Conclusion
Some yoga postures show promise for use as a preventative therapy to stabilize the scapula and potentially prevent shoulder dysfunction.
Research and yoga
Welcome to our new series highlighting current research on yoga! In the past few years, researchers have been taking a closer look at what’s actually happening when we practice yoga. In this series, we want to share some of that research with you. Each month, we’ll summarize one research study and share the results that the authors found. Topics will range from anatomy to the nervous system to mindfulness and more.
In this first research study, summarized in the post below, we take a look at what yoga postures can do for our shoulders. The authors evaluated whether several yoga postures stabilize the shoulder blade using the muscular engagement of serratus anterior and trapezius and potentially prevent a common source of shoulder pain called subacromial impingement syndrome.
Background
Shoulder pain is very common in the general population. In particular, subacromial impingement is a frequent cause of shoulder pain. Subacromial impingement occurs when there is reduced space between the head of the humerus and the acromion process. The head of the humerus is the ball at the top of the upper arm bone (the humerus) that fits into the socket to create the shoulder joint. The acromion process is the bony ledge of the scapula that sticks out over the top of the humerus. As a result of the reduced space between the head of the humerus and the acromion process, tissues in that area get compressed.
Strengthening the muscles that stabilize the scapula can help maintain the subacromial space. And that is necessary for reducing the compression of tissues and reducing shoulder pain. The trapezius and serratus anterior are key muscles for maintaining stability of the scapula. The researchers in this study explored several yoga postures as one possible way of developing the necessary strength in the right places to stabilize the scapula and maintain the subacromial space.
Research question
How active are the scapular stabilizing muscles, specifically serratus anterior and the upper, middle, and lower trapezius, in yoga postures (crow pose, dancer’s pose, locust, downward dog, modified plank with hands clasped, modified plank with hands shoulder-width, reverse tabletop, side angle, side plank, tree pose, upward dog, warrior 2)?
Research methods
Twenty women participated in this study. All had healthy shoulders. They had no shoulder injuries or pain. The researchers used electromyography to measure the muscle activity of serratus anterior, upper trapezius, middle trapezius, and lower trapezius in each of the yoga postures. Electromyography is a method of measuring the activity of a muscle.
The research team attached electrodes to the muscles being evaluated for each participant. The participants then moved through a series of yoga postures. The participants held each yoga posture for 5 seconds and repeated each posture three times. Each participant did the same yoga postures, but the order of the postures varied for each of the participants. The researchers randomly determined the order of the postures that each participant did. This allowed them to study the impact of individual postures on muscle activation, rather than the effect of a particular series of postures.
Results
The researchers found that some yoga postures stabilize the shoulder blade. In general, the yoga postures studied generated more muscle activity from serratus anterior than from all three areas of the trapezius. Four postures generated at least moderate muscle activity from the serratus anterior. Those poses were: crow pose, dancer’s pose, modified plank pose with clasped hands, and modified plank pose with hands shoulder-width apart. Of the yoga postures evaluated, locust pose with the arms forward generated the most muscle activity from areas of the trapezius.
Why is this relevant to yoga practitioners?
There are a couple of reasons why the results of this particular research study are relevant to yoga practitioners. Many common yoga styles, including basically all the variations of vinyasa-style practice, include transitions that move through chaturanga or plank position. In chaturanga, or any plank position, it’s important that we stabilize the scapula to avoid straining the rest of the shoulder girdle. I’ve shared in other articles and in many workshops, that I think one key to stabilizing the scapula is activating the serratus anterior muscle. This research supports that understanding.
While participants in this study had some previous experience with yoga, it’s not clear whether any participants were long-term students of yoga. It’s possible that serratus anterior or the trapezius could be activated even more effectively if yoga instructors coached participants on how to activate these muscles and they practiced that over a period of time.
Conclusion
This research suggests that some yoga postures stabilize the shoulder blade by actively engaging serratus anterior and the trapezius muscles. This muscle engagement works to stabilize the scapula. And, in that way, it potentially contributes to the long-term healing process for shoulder pain that occurs as a result of reduced subacromial space. It makes sense that if we engage these muscles to stabilize the scapula in yoga before our subacromial space has been reduced, we can prevent some incidences of shoulder pain.
What we don’t learn from the research is how quickly the serratus anterior and the trapezius muscles fatigue when we activate them to stabilize the scapula. It’s still up to each student to determine how many plank poses or chaturangas is too many. Perhaps future research will also give us a sense of this as well.
