Research Review: Exercises for scapular muscle balance
By Lynn Willford PT, MS, Cert MDT
Edited by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS
Original Citation: Cools, A.M., Dewitte, V., Lanszweert, F., Notebaert, D., Roets, A., Soetens, B., Cagnie, B., Witvrouw, E.E. (2007) Rehabilitation of Scapular Muscle Balance. Which Exercises to Prescribe? Am J Sports Med, 35(10), 1744-1751. - ABSTRACT
Why is this relevant?: Shoulder pain is a common complaint that may interfere with daily activity, and is one of the most common reasons for someone to seek-out a rehabilitation specialist. Often times scapulothoracic dysfunction contributes to the underlying shoulder pathology and knowing what exercises are best to restore balanced muscle activity will optimize the chances of full recovery.
Prone Cobra on Ball - http://lauralovesfitness.files.wordpress.com/2013/01/dsc_35341.jpg
Study Summary
| Study Design | Controlled Laboratory Study. |
| Level of Evidence | Level III; evidence obtained from well-designed controlled trials without randomization |
| Subject Demographics |
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| Outcome Measures | Electromyographic activity of the 3 divisions of the trapezius muscle (lower, middle and upper) and the serratus anterior was measured in 45 healthy subjects performing 12 commonly prescribed scapular exercises. Surface electromyography was used to measure the activity in 3 phases - concentric, isometric and eccentric. Specifically the ratio of the activity of the upper trapezius (UT) with respect to the middle trapezius (MT), lower trapezius (LT) and the serratus anterior (SA) was determined. Values < 100% reflect activity of the MT, LT or SA being superior compared with that of the UT. Values >100% reflect muscle activity of the UT exceeding that of the other scapular muscles. Ratios significantly lower than 100% were relevant to answering the question of which exercises were the best in minimally activating the UT. This group was then subdivided into 3 groups based on ratio: 100%-80% (moderate), 80%-60% (good) and <60% (excellent). Within each subgroup, the 3 best exercises were further analyzed by phase of contraction (concentric, isometric and eccentric). The researchers determined that the best exercises were those with a ratio of < 60% in all 3 phases (Category 1). The 3 best exercises based on these criteria were then further analyzed to see whether some phases were better than others for enhancing ratios. |
| Results | Side-lying forward flexion, side-lying external rotation, horizontal abduction with external rotation had the lowest UT/LT ratio. Side-lying forward flexion, side-lying external rotation and prone extension had the lowest UT/MT ratio. No exercise met all the criteria for Category 1 for the UT/SA ratio. However one exercise, the high row, met the criteria for Category 2 (all 3 phases with a ratio < 80% and at least one phase < 60%). Two exercises, standing forward flexion and scaption with external rotation, met the criteria for Category 3 (all 3 phases with < 100% with at least one phase between the 60-80% ratio).The isometric phase overall revealed the lowest UT/LT and UT/MT ratios |
| Conclusions | This research provides us with sound data of the best exercises to use when the desire is to activate the lower and middle trapezius but not the upper trapezius. |
| Conclusions of the Researchers | These researchers studied the activation of the 3 trapezius muscle parts and the serratus anterior during 12 commonly used shoulder girdle exercises and calculated intermuscular and intramuscular balance ratios. Based on their results it is suggested that side-lying forward flexion, side-lying external rotation, prone horizontal abduction with external rotation, and prone extension are the best exercises to promote LT and MT activity with minimal activation of the UT. |
https://upload.wikimedia.org/wikipedia/commons/2/2d/Trapezius_Gray409.PNG
Review & Commentary: Shoulder pain in general, and impingement symptoms in particular, have been a focus of researchers for decades. Most recently the emphasis has been on the role that the scapula plays in shoulder mechanics and the effect muscle recruitment has on scapular kinematics. A question posed by many researchers and clinicians is whether the onset of shoulder pain is related to actual strength deficits or is the product of scapular muscle imbalances. If the upper trapezius is highly active and the lower trapezius is less active does this contribute to abnormal scapular motion? A result of the research surrounding this question is training of the scapular muscles becoming common place in treatment of the painful shoulder. It is, however, challenging to restore the ideal muscular balance that promotes the co-activation necessary for good mechanics and restoration of normal scapulothoracic movement.
This research analyzed 12 exercises commonly used for trapezius training. These exercises were performed in either standing, prone, sitting or a side-lying position and included shoulder abduction, forward flexion, rows(high and low), horizontal abduction, extension, scaption and external rotation. The exercises were randomized for each subject and 5 trials with a 3 second rest between were performed for each. The results of this EMG study supported the hypothesis that it is possible to select exercises that optimize scapular muscle balance ratios.
12 Exercises Analyzed in Study:
- Prone shoulder abduction
- Forward flexion
- Foward flexion in side-lying position
- High row
- Horizontal abduction
- Horizontal abduction with external rotation
- Low row (elbows extended)
- Low row 2 (with elbows flexed)
- Prone extension
- Rowing in sitting position
- Scaption with external rotation
- Side-lying external rotation
The methodology of this study had some limitations that were readily acknowledged by the researchers. Data was gathered through the use of surface electromyography which leaves room for error. Using surface electrodes rather than needle/intramuscular EMG can result in skin displacement, movement artifact and cross-talk between muscles deep or adjacent to the muscles being assessed in the study. A second weakness of the study was that the exercises were non-functional in nature; were single plane motions, and most were performed in a lying position. Another potential weakness of this study is that all of the subjects were young and healthy, without history of shoulder impingement or pain. Although, it may be possible to refine exercise selection using the EMG data of this study, consideration should be given to how this information may be applied to more functional activities and how pain and dysfunction may alter motion and recruitment.
Why is this study important? This study is important because it compares various commonly used exercises for rehabilitating shoulder pain with scapular dyskinesis in an attempt to optimize exercise selection.
How does it affect practice? This research provides information that allows the clinician to make better decisions regarding the choice of exercises when correcting a scapular muscle imbalance; a common source of abnormal shoulder mechanics that either already has or will lead to pain and dysfunction. Choosing exercises that are more effective, and eliminating those exercises that are less effective, will enhance the efficiency and efficacy of intervention. Based on the results of this study it is suggested that side-lying forward flexion, side-lying external rotation, prone horizontal abduction with external rotation, and prone extension are the best exercises to promote lower trapezius and middle trapezius (LT & MT) activity with minimal activation of the Upper Trapezius (UT). These exercises are similar to the cobra, "I-T-Y", and chest out thumbs out exercises used by the Brookbush Institute (Discussed below with video).
How does it relate to Brookbush Institute Content? This study systematically analyzed muscle activity of 12 exercises commonly used to correct scapular muscle imbalance that may lead to the development of a compensation patterns, resulting dyskinesis and pain. In the predictive model of Upper Body Dysfunction (UBD) , the Brookbush Institute details the intermuscular coordination and arthrokinatic dyskinesis associated with this dysfunction and recommends exercise for optimizing muscle length and activity. This study specifically addresses those muscles thought to be long/under-active (lower and middle trapezius ) while minimizing synergistic dominance of the upper trapezius . The exercises found most effective closely resemble the "chest out-thumbs out" exercise used during external rotator activation , the "cobra exercise" used during trapezius activation , and the "ITY" used during both trapezius and serratus anterior activation . Please see videos below.
External Rotator Activation (Chest Out, Thumbs Out)
Prone Ball ITY
Prone Cobra on Foam Roll
Serratus Anterior Activation (Flexion/Scaption against Wall)
© 2015 Brent Brookbush
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