Author Names

Wong, C., Conway, L., Fleming, G., Gopie, C., Liebeskind, D., Xue, S.

Reviewer Name

Maria Hamilton, SPT

Reviewer Affiliations

Duke University School of Medicine, Doctor of Physical Therapy Division

 

Paper Abstract

Clinical Scenario: Many people with lower quarter musculoskeletal dysfunction present with muscle weakness. Strength training hypertrophies muscle and increases strength, but often requires periods over 6 weeks, which can exceed the episode of care. Weakness can persist despite muscle hypertrophy, particularly in the early stages of joint pathology or in the presence of limb or spinal joint hypomobility, which may inhibit muscle activation. Emerging evidence suggests spinal manipulation can increase short-term strength. Screening for specific muscle weakness that could benefit from manipulation to particular spinal segments could facilitate efficient clinical intervention. Although the neuromuscular mechanisms through which manipulation can increase strength remains a topic of investigation, immediate gains can benefit patients by jump-starting an exercise program to train new muscle function gained and enhancing the motivation to continue strengthening. Evidence from randomized controlled trials would provide support for using manipulation to increase muscle strength, while studying healthy people would eliminate confounding factors, such as pain and pathology.  Clinical Question: Does randomized controlled trial-level evidence support the concept that a single lumbar spine manipulation session can increase lower-limb strength in healthy individuals?  Summary of Key Findings: Level 1b evidence of moderate quality from 3 randomized controlled trials showed immediate small to large effect size muscle strength increases immediately after lumbar spine manipulation.  Clinical Bottom Line: Lumbar spine manipulation can result in immediate lower-limb isometric strength increases. While healthy people with normal muscle strength may improve minimally, joint manipulation for people with knee and hip weakness who are otherwise healthy can result in large effect size strength gains.  Strength of Recommendation: Moderate quality level 1b evidence from randomized controlled trials with small samples support the use of spinal manipulation to immediately increase lower-limb strength. Additional studies investigating impact on strength and function immediately in people with musculoskeletal pathology are warranted.

 

NIH Risk of Bias Tool

Quality Assessment of Systematic Reviews and Meta-Analyses

Is the review based on a focused question that is adequately formulated and described?

  • Yes

Were eligibility criteria for included and excluded studies predefined and specified?

  • Yes

Did the literature search strategy use a comprehensive, systematic approach?

  • Yes

Were titles, abstracts, and full-text articles dually and independently reviewed for inclusion and exclusion to minimize bias?

  • Cannot Determine, Not Reported, Not Applicable

Was the quality of each included study rated independently by two or more reviewers using a standard method to appraise its internal validity?

  • Yes

Were the included studies listed along with important characteristics and results of each study?

Was publication bias assessed?

  • Yes

Was heterogeneity assessed? (This question applies only to meta-analyses.)

  • Cannot Determine, Not Reported, Not Applicable

 

Key Finding #1

In a study where a high-grade lumbopelvic joint thrust manipulation was used, patients experienced a significant increased in quad-force output and activation immediately after joint manipulation in comparison to the PROM group and prone extension group.

Key Finding #2

In a study where a high-velocity, low-amplitude thrust at end-range (targeted specific nerve roots) was performed, there was a reduction in strength differences between limbs (for knee flexion and hip flexion).

Key Finding #3

In a study where a high-velocity, low-amplitude thrust at end-range (targeted specific nerve roots) was performed, spinal manipulation increased weak limb strength (knee flexion and hip flexion) during hip abduction.

Key Finding #4

In a study where grade III spinal rotation manipulation at L2-L3 was performed, the group who received spinal rotation manipulation experienced greater positive percentage change in hip flexor torque in comparison.

 

Please provide your summary of the paper

This systematic review focused on three studies that investigated the effect of various forms of spinal manipulation on lower extremity strength in healthy individuals. Each study was a randomized controlled trial that had level 1b evidence suggesting that spinal manipulation led to immediate increases in isometric muscle strength in the lower extremity.

Please provide your clinical interpretation of this paper.  Include how this study may impact clinical practice and how the results can be implemented.

Even though these studies show that there are immediate effects of various forms of spinal manipulation on isometric lower extremity strength, these results are only after a single session. In addition, there was no follow-up after providing the single spinal manipulation. It would be more useful clinically to look at the long-term effects of spinal manipulation on lower extremity strength to see if this a useful intervention for those who may have weakness in those extremities. Additionally, all three studies had small sample sizes, affecting the true significance of the results.