Short-Term Effects of Lower Thoracic Manipulation on Lower Trapezius Muscle Strength

Research Review: Short-Term Effects of Lower Thoracic Manipulation on Lower Trapezius Muscle Strength

By Nicholas Rolnick PT, DPT, MS, CSCS

Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Cleland J, Selleck B, Stowell T, Brown L, Alberini S, St. Cyr H, Caron T. Short-term Effects of Thoracic Manipulation on Lower Trapezius Muscle Strength. Journal of Manual & Manipulative Therapy. 2004; 12(2): 82-90. ABSTRACT .

Why the Study is Relevant: The lower trapezius assists the serratus anterior in upward rotation of the scapula, a motion that is essential for elevating the arm overhead (flexion and/or abduction) (1). The lower trapezius has a propensity toward under-activity and latent recruitment in individuals exhibiting shoulder, thoracic spine and/or cervical dysfunction (3-7). While strengthening/activation techniques are commonly used to address this issue, practitioners have noted altered muscle recruitment post joint mobilization/manipulation. This 2004 study from Franklin Pierce College in New Hampshire was the first study to investigate the acute effects of a lower thoracic manipulation on lower trapezius muscle strength in 40 asymptomatic individuals. The results support performing thoracic spine manipulation prior to applying strengthening techniques to the lower trapezius .

Caption: Cadaver Dissection dipicting the trapezius muscle (especially the lower trapezius), with labels.

Trapezius Muscle - By Anatomist90 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=17900189

Study Summary

Caption: SA Thoracic Spine Mobilization

The Brookbush Institute currently recommends self-administered thoracic spine mobilization prior to neuromuscular re-education and strengthening of the lower trapezius.

Review & Commentary:

This study was the first to investigate the immediate effects of a lower thoracic spine joint manipulation on lower trapezius muscle strength in asymptomatic men and women. The findings add to the growing body of literature on the acute effects of joint mobilization /manipulation on muscle strength.

The study had many methodological strengths, including:

• The randomized-controlled design and blinding of the examiner reduced the risk of observer bias.
• The manipulation that was performed is a common treatment technique used in clinical practice to address thoracic hypomobility. This increases the generalizability of the study.
• The clear description of the protocol will allow replication of the study with other populations.
• The findings provided information that filled a gap in research. Prior to this study, it was unknown whether thoracic joint manipulation could improve lower trapezius muscle strength.

Weaknesses that should be noted prior to clinical integration of the findings include:

• The reliability of the clinician's assessment of thoracic restriction (hypomobility) was not determined.
• The lack of follow-up and design of the study do not permit speculation on the long-term effects of thoracic manipulation on lower trapezius strength.
• The participants were asymptomatic. It is unknown whether similar effects would be observed in individuals with pain.

How This Study is Important:

This study adds to a growing body of research that suggests that joint mobilizations/manipulations have an immediate effect on muscle recruitment and activity. This relationship implies not only that the human body is a holistic system, but that joint mobilizations/manipulations may be an important component of an integrated approach. Further, this study may suggest that manipulations are better than mobilizations. While a prior study with similar research methods demonstrated that mobilizations improved lower trapezius strength by 6% from baseline (2), this study demonstrated that thoracic manipulations increased strength by 14% from baseline. Although it would be in accurate to call this a "result," or assert this as a certainty, as two separate studies cannot be directly compared, future research should be performed to compare the two techniques.

How the Findings Apply to Practice:

Human movement professionals should incorporate lower thoracic spine mobilizations and/or manipulations (if within scope of practice) if the intent of intervention is to improve lower trapezius muscle strength. The Brookbush Institute suggests that this study, as well as other studies demonstrating altered muscle recruitment post mobilization, imply that joint mobilizations should be performed prior to performing activation techniques for optimal results.

How does it relate to Brookbush Institute Content?

The findings of this study support the Brookbush Institute's (BI) integrated approach and order of treatment for those exhibiting Upper Body Dysfunction (UBD ). Further, this study implicates the lower trapezius as under-active, which is also in congruence with the UBD model. While the UBD model implied that thoracic mobilization and lower trapezius activation techniques would be beneficial for separate reasons (under-activity and hypomobility), this study establishes a direct relationship between the two. BI does recommend that release techniques precede mobilization and activation techniques.

All human movement professionals should add self-administered thoracic spine mobilizations exercises to their repertoire, not just for thoracic mobility, but to assist in optimizing thoracic and scapular muscle recruitment. Human movement professionals who have a scope of practice that includes joint based approaches (DO's, DPTs, DCs, ATCs) should consider and practice manual mobilization and manipulation techniques for thoracic spine. Future videos will focus on manual joint mobilization and manipulation techniques.

The following videos illustrate common assessment techniques and interventions used to identify and treat relative inhibition of the lower trapezius muscle.

Overhead Squat Assessment - Arms Fall

Lower Trapezius Manual Muscle Test

Self-Administered Thoracic Spine Mobilization

Self-Administered Thoracic Spine Rotation Mobilization

Trapezius Isolated Activation

Bibliography:

1. Cools, A.M., Witvrouw, E.E., Declercq, G.A., Danneels, L.A., Cambier, D.C. (2003) Scapular muscle recruitment patterns: Trapezius muscle latency with and without impingement symptoms. The American Journal of Sports Medicine 31(4). 542-549
2. Liebler EJ, Tufano-Coors L, Douris P, Makofsky HW, McKenna R, Michels C, Rattray S. The effect on thoracic spine mobilization on lower trapezius strength testing. J Manual manipulative Ther. 2001; 9(4): 207-212.
3. Scovazzo ML, Browne A, Pink M, et. al.: The Painful shoulder during freestyle swimming. Am J Sports Med 19(6):577-582, 1991
4. Ludewig PM, Cook TM (2000) Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement. Phys Ther 80(3):276–291
5. Cools, A.M., Witvrouw, E.E., Declercq, G.A., Danneels, L.A., Cambier, D.C. (2003) Scapular muscle recruitment patterns: Trapezius muscle latency with and without impingement symptoms.
6. Kwon JW, Son SM, Lee NK. (2015). Changes in upper-extremity muscle activities due to head position in subjects with a forward head posture and rounded shoulders. J Phys Ther Sci. 27: 1739-1742
7. Wegner, S., Jull, G., O’Leary, S., & Johnston, V. (2010). The effect of a scapular postural correction strategy on trapezius activity in patients with neck pain. Manual therapy, 15(6), 562-566

© 2017 Brent Brookbush

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