Selective recruitment of the lower fibers of the trapezius muscle
Arlotta M, Lovasco G, McLean L. J Electromyogr Kinesiol. 2011 Jun;21(3):403-10. Epub 2010 Dec 8.
The scapula has been shown to play a critical role in shoulder function. The scapular stabilizing muscles work together to provide dynamic stability. Some research has demonstrated that the lower trapezius can develop inhibition and the upper trapezius becomes hyperactive in pathologic shoulders. This demonstrates the need for exercises that maximize lower trapezius activity and minimal upper trapezius activity. Therefore, the authors examined a series of rehabilitation exercises to determine the amount of electromyography (EMG; muscle) activity that is produced in each division of the trapezius muscle (upper, middle, and lower)They evaluated muscle activity in 18 healthy individuals with no prior history of shoulder injury or participation in overhead sports. Bilateral EMG was collected during five difference exercises (Latissimus Pull-down, Prone Row, Prone V-Raise, Posterior Fly, and Modified Prone Cobra). The order of exercises was randomly selected. They examined the peak EMG activity and also calculated EMG isolation which was defined as division of interest divided by EMG UT +EMG MT+ EMG LT. They found that there were differences between sex and therefore the data was analyzed separately for each sex. In males the prone row, posterior fly, and modified prone cobra generated the highest activity for the lower trapezius. For females the modified prone cobra and the prone row generated highest activity compared to the other exercises. For both males and females the modified prone cobra, prone row, and latissimus pull down had the most isolated lower trapezius activity.
This study presents very clinically relevant data to help justify an exercise selection for patients with lower trapezius inhibition. In addition to determining exercises that produce maximal lower trapezius activation, the activation of the upper trapezius needs to be considered. This study identifies several exercises that can be performed with a more optimal ratio of lower trapezius to upper trapezius activation. In this study these exercises were performed bilaterally and therefore should be perform in a similar fashion clinically. It would have been interesting if the same results would have been produced if the exercises were only done unilaterally. I believe the same isolation would have been produced, however the activation level would have been reduced. Several studies have demonstrated a neuromuscular cross over effect that improves strength and activation when performing exercises bilaterally. The selected exercises are quite common, at least in my experience (although I call them by different names). What are others experience with these exercises? Have you heard or used them in the past? Have you had success?
Written by: Stephen Thomas
Reviewed by: Jeffrey Driban
Latissimus Pull-down
Prone Row
Prone V-Raise
Posterior Fly
Modified Prone Cobra
Abstract
Introduction
We aimed to determine the effectiveness of five isometric exercises at maximally activating the lower trapezius muscle in healthy subjects.
Methods
Surface electromyography data were recorded from the upper, middle, and lower fibers of the trapezius muscle bilaterally while 18 healthy subjects performed five different exercises: Latissimus Pull-down, Prone Row, Prone V-Raise, Posterior Fly and Modified Prone Cobra. The peak activation was determined from the rectified and smoothed data to determine which exercise generated the highest amount of lower trapezius activity, and to determine which exercise best resulted in activation of the lower fibers of trapezius while minimizing activation of the upper and middle fibers of trapezius.
Results
Males and females demonstrated different patterns of lower trapezius recruitment and therefore the data were analyzed separately for each sex. For the males, the Prone Row exercise (2.84
±1.67mV), the Posterior Fly (2.23±1.00mV) and the Modified Prone Cobra (2.26±1.19mV) exercises generated the highest EMG activity in the lower trapezius muscle. For the females, the Modified Prone Cobra (2.40±1.32mV) and the Prone Row (2.37±1.14mV) exercises generated higher activation than the Latissimus Pull Down (1.04±0.56mV), the Posterior Fly (1.62±1.044mV) and the Prone V-Raise (1.32±1.07mV). In both sexes, the Modified Prone Cobra, the Prone Row and the Latissimus Pull Down outperformed the other exercises in terms of maximizing lower trapezius activation while minimizing activation of the upper and middle fibers of trapezius. The Modified Prone Cobra showed lower relative activation of the upper trapezius muscle than did the Prone Row exercise.
Conclusion
The Modified Prone Cobra and Prone Row exercises are the most effective exercises for targeted strengthening of the lower trapezius muscle in both sexes. The Modified Prone Cobra is somewhat better than the Prone Row due to the low activation of the upper trapezius muscle during this exercise. The Modified Prone Cobra exercise should therefore be considered as a manual muscle test position and as a strengthening exercise for the lower trapezius muscle fibers.
prone cobra - lower trapezius strength