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
- age 18-40
- healthy shoulder function
- had some yoga experience
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).
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.
Some yoga postures show promise for use as a preventative therapy to stabilize the scapula and potentially prevent shoulder dysfunction.
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.
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 and support maintaining the subacromial space 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.
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)?
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.
Each participant had electrodes attached to the muscles being evaluated, and then moved through the series of yoga postures being studied. The participants held each yoga posture for 5 seconds and repeated each posture 3 times. The same yoga postures were done by each participant, but the order of the postures was different for each of the participants. The order of the postures that each participant did was randomly determined, so that the researchers could study the impact of the individual postures on muscle activation, rather than the effect of a particular series of postures.
The researchers did find 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 position or plank position. In chaturanga, or any plank position, it’s important that the scapula be stabilized to avoid strain to the rest of the shoulder girdle. I’ve shared in other articles and in many workshops, that I think one key to the stabilization of the scapula is activation of the serratus anterior muscle. This research supports that understanding.
While participants in this study had some previous experience with yoga, the study does not report that they were long-term students of yoga. It’s possible that the postures studied could even more effectively activate serratus anterior or the trapezius if participants doing the postures were coached on how to direct their attention to using these muscles and practiced that over a period of time.
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.
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