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Tuesday, June 6, 2023

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

Brent Brookbush

Brent Brookbush


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 .

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

Study Design Randomized-controlled trial
Level of EvidenceIB - evidence from at least one randomized-controlled trial
Subject CharacteristicsDemographics:
  • Age: 18-56
  • Gender: 21 females; 19 males
  • Convenience sample from southern New Hampshire

Inclusion Criteria:

  • Resistance training experience, with a current training program of at least three resistance sessions per week, with loads between 40%-90% of 1 repetition maximum.
  • No upper-body injuries within the past year

Exclusion Criteria:

  • Back or upper extremity pain within the past year
  • Contraindications to spinal manipulation including involvement of nerve roots, spinal cord, cauda equina syndrome, or any diseases affecting the spine or ligaments of the spine
  • All participants underwent a musculoskeletal exam of the thoracic spine and bilateral upper extremities prior to baseline measurements.
    • The exam included - a posture observation and assessment of the active thoracic flexion/extension range of motion - lower trapezius muscle strength and a passive segmental spine motion assessment of T6-T12, performed while seated.

  • Lower trapezius strength was recorded using a Nicholas Manual Muscle Tester with test-retest reliability established at 0.92 (excellent).
    • Each participant was placed in a supine position, with hips and knees flexed to 90 degrees to minimize lumbar lordosis.
    • The participant's arms were passively abducted and flexed to 150 degrees while maintaining full extension of the elbows.
    • The recording dynamometer was placed 3 cm proximal to the wrist joint.
    • The positions of the participant's arms were measured to maximize test-retest reliability.
    • Each participant pushed into the dynamometer with maximum force in scapular plane abduction for 5 seconds. This was repeated 3 times, with 30-second rest periods between each repetition.

  • Participants were randomized into either a control group (CON) that did not receive spinal manipulation or an experimental group (EXP) that did receive spinal manipulation.
  • Participants in the EXP group received spinal manipulation at each thoracic vertebral segment that was recorded as restricted based on the passive segmental spine motion assessment.
    • The manipulation was performed with the participant in a supine position with his/her arms crossed across the chest.
    • The clinician rolled the participant to his/her side and placed his hand underneath the spine in a "pistol grip" at the segment inferior to the one targeted by the manipulation.
    • The clinician positioned the participant in side-bending and rotation to maximize closure of the segment and delivered a high velocity, low amplitude thrust at the resistance barrier.

  • Participants in the CON group were positioned similarly to the EXP group, but the clinician used an "open hand" and did not perform a high velocity, low amplitude thrust at the resistance barrier. The procedure was repeated at each restricted thoracic vertebral segment.
  • Following the intervention, the participant's lower trapezius strength was re-measured by a clinician blinded to the group categorizations.
Data Collection and Analysis
  • An independent t-test was used to compare the mean change in pre-test and post-test lower trapezius muscle strength between the CON and EXP groups. Significance was set at 0.05.
Outcome Measures Lower trapezius muscle strength
  • Increase in peak strength (in kg)
  • Percentage strength increase (in %)
  • Gender differences (in kg/%)
ResultsLower trapezius muscle strength improved in both groups.
  • EXP group: started at 11.4 kg (±2.5 = standard deviation) and improved to 13 kg (±2.4)
  • CON group: started at 12.2 kg (±4.8) and improved to 12.5 kg (±4.6) (p > 0.05 for statistical significance between groups pre- and post-intervention).

Peak strength increased in both groups.

  • EXP group: 1.64 kg (±1.8)
  • CON group: 0.4 kg (±0.44) (p = 0.022 for significance between groups).

Percentage strength increased in both groups.

  • EXP group: 14.5% (±7.8)
  • CON group: 3.9% (±4.7) (p = 0.020 for significance between groups).

Gender did not influence the magnitude of lower trapezius strength measures in either group (p > 0.05).

Our Conclusions

The results of this study support the hypothesis of a holistic human movement system in which techniques intended to effect a tissue type or structure, will also effect other proximal tissues and structures.  Further, this study highlights an added benefit of a commonly used technique, and may be evidence of the positive impact of using joint mobilizations in an integrated treatment approach.

Specifically, this study supports performing thoracic spine manipulation prior to muscle activation/strengthening techniques for those exhibiting lower trapezius muscle under-activity/weakness.

Researchers' Conclusions

Lower thoracic spine joint manipulation is effective at producing immediate increases in lower trapezius strength in asymptomatic men and women.  Joint mobilizations and manipulations may be effective adjuncts to rehabilitation and strengthening programs.

SA Thoracic Spine Mobilization
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


  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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