The acute effects of spinal manipulation on neuromuscular function in asymptomatic individuals: A preliminary study

Review of effects of spinal manipulative therapy on neurological symptoms

BACKGROUND

Neurological disorders are the leading cause of disability in the world. Neurological symptoms significantly affect the well-being of the individual. Spinal manipulative therapy (SMT) is a complementary method often used for people with neurological disorders.

OBJECTIVE

This study aimed to review the existing literature on the effects of SMT on common clinical symptoms of neurologic disorders and the quality of life.

METHODS

Narrative review was conducted through the literature published between January 2000 and April 2020 in English. The search was performed across four databases: PubMed, Google Scholar, PEDro, and Index to Chiropractic Literature. We used combinations of keywords related to SMT, neurological symptoms, and quality of life. Studies on both symptomatic and asymptomatic populations of different ages were included.

RESULTS

35 articles were selected. Evidence for the administration of SMT for neurological symptoms is insufficient and sparse. Most studies focused on the effects of SMT on pain, revealing its benefits for spinal pain. SMT may increase strength in asymptomatic people and populations with spinal pain and stroke. SMT was reported to affect spasticity, muscle stiffness, motor function, autonomic function, and balance problems, but these studies were limited in number to make conclusions. An important finding was the positive influence of SMT on the quality of life in people with spinal pain, balance impairments, and cerebral palsy.

CONCLUSION

SMT may be beneficial for the symptomatic treatment of neurological disorders. SMT can positively affect the quality of life. However, limited evidence is available, and further high-quality research is required.

Evidence for increased neuromuscular drive following spinal manipulation in individuals with subacromial pain syndrome

BACKGROUND

Thoracic spinal manipulation can improve pain and function in individuals with shoulder pain; however, the mechanisms underlying these benefits remain unclear. Here, we evaluated the effects of thoracic spinal manipulation on muscle activity, as alteration in muscle activity is a key impairment for those with shoulder pain. We also evaluated the relationship between changes in muscle activity and clinical outcomes, to characterize the meaningful context of a change in neuromuscular drive.

METHODS

Participants with shoulder pain related to subacromial pain syndrome (n = 28) received thoracic manipulation of low amplitude high velocity thrusts to the lower, middle and upper thoracic spine. Electromyographic muscle activity (trapezius-upper, middle, lower; serratus anterior; deltoid; infraspinatus) and shoulder pain (11-point scale) was collected pre and post-manipulation during arm elevation, and normalized to a reference contraction. Clinical benefits were assessed using the Pennsylvania Shoulder Score (Penn) at baseline and 2-3 days post-intervention.

FINDINGS

A significant increase in muscle activity was observed during arm ascent (p = 0.002). Using backward stepwise regression analysis, a specific increase in the serratus anterior muscle activity during arm elevation explained improved Penn scores following post-manipulation (p < 0.05).

INTERPRETATION

Thoracic spinal manipulation immediately increases neuromuscular drive. In addition, increased serratus anterior muscle activity, a key muscle for scapular motion, is associated with short-term improvements in shoulder clinical outcomes.

Throwing performance after high-velocity low-amplitude thrust manipulation at the cervicothoracic and thoracolumbar junction in elite female water polo players: a randomized blind cross-over study

BACKGROUND

The effect of high-velocity low-amplitude (HVLA) thrust manipulation at the cervicothoracic and thoracolumbar junction in healthy elite female water polo players on throwing performance is unknown.

METHODS

Ten healthy members of the Dutch National female water polo team participated in this randomized blind cross-over study. All received a HVLA manipulation and a sham manipulation at the cervicothoracic and thoracolumbar junction. Hereafter maximum throwing speed, range of motion and isometric strength were measured at 1 hour, 48 hours and 4 weeks follow-up.

RESULTS

No significant differences in maximum throwing speed was found between HVLA and sham manipulation. In the non-dominant shoulder external rotation increased significantly (5.3±6.7°) 48 hours after sham manipulation, this effect was not considered clinically significant and diminished after four weeks.

CONCLUSIONS

Our results suggest that HVLA and sham manipulation had no effect on shot velocity or shoulder mobility and the same effect on shoulder strength in healthy elite female water polo players. The common use of cervicothoracic and thoracolumbar HVLA manipulation for improving performance in this specific group of athletes is therefore questionable.

The Acute Effects of Manual and Instrument-Assisted Cervical Spine Manipulation on Pressure Pain Threshold, Pressure Pain Perception, and Muscle-Related Variables in Asymptomatic Subjects: A Randomized Controlled Trial

OBJECTIVE

The purpose of this study was to compare the immediate effects in asymptomatic participants of manual and instrument-assisted cervical manipulation on pressure pain thresholds, pressure pain perception, and muscle mechanical properties (tone, stiffness, and elasticity) over muscles anatomically related and unrelated to the manipulated level.

METHODS

Fifty-nine asymptomatic participants (34 women and 25 men; age [mean ± standard deviation] = 21.1 ± 1.6 years) were randomly assigned to 4 groups in a double-blind, randomized, placebo-controlled trial. Two groups received cervical (C3/C4) manipulation, 1 manual and the other instrument-assisted; the third group received a sham manipulation; and the fourth group served as the control. Bilateral pressure pain threshold, pressure pain perception, muscle tone, stiffness, and elasticity in the upper trapezius and biceps brachii were evaluated before and immediately after the interventions.

RESULTS

At baseline, there were no differences among the groups on any variable. After the interventions, a significant increase in pressure pain threshold was observed with both manual and instrument-assisted manipulation at local and distal sites (P < .05), whereas no changes were observed in either the control or the placebo group. The perception of pain pressure did not change significantly in any group. The interventions did not promote any statistically significant differences in muscle tone, elasticity, or stiffness at any site (local or distal).

CONCLUSION

Cervical (C3/C4) manual and instrument-assisted manipulations produced an increase in pressure pain threshold bilaterally and over muscles related and unrelated to the vertebral segment, but had no effect on muscle tone, elasticity, or stiffness.

Short-Term Effects of Global Pelvic Manipulation on Knee Joint Position Sense in Asymptomatic Participants: A Double-Blind Randomized Controlled Trial

OBJECTIVE

The purpose of this study was to evaluate short-term effects of the global pelvic manipulation (GPM) on knee joint position sense (JPS).

METHODS

This randomized, controlled double-blind trial included 26 asymptomatic participants (X¯± 25.3; standard deviation ± 4.4 years) who were randomly allocated into 2 groups. Sixteen participants were allocated into the experimental group, in which GPM was performed, and the rest of the participants (n = 10) were included in the control group, which received sham ultrasound therapy. Each participant attended 1 session only, and the evaluations were assessed pretreatment and 5 minutes posttreatment through an isokinetic dynamometer (Biodex Medical Systems), in which the data regarding knee JPS ipsilateral to the manipulated sacroiliac joint were collected. Mann-Whitney and Wilcoxon tests were used, with a 95% significance level.

RESULTS

There were no statistically significant differences between the groups concerning active and passive JPS at 30° and 60° (P > .05). The results showed a lack of significant differences between the moments in both groups (P > .05).

CONCLUSION

This investigation demonstrated that GPM, with high-velocity low-amplitude thrust, has no effect on knee JPS, suggesting that this manipulative technique does not have a relative effect on muscle spindles and Golgi tendon organ activation in asymptomatic participants.

The Effectiveness of Spinal Manipulation in Increasing Muscle Strength in Healthy Individuals: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to systematically review the effects of spinal manipulation on muscular strength in healthy individuals and conduct a meta-analysis to appraise the quality of evidence.

METHODS

Articles were searched and retrieved from MEDLINE, EMBASE, CINAHL, Cochrane Library, PubMed, Academic Search Premier, SPORTDiscus, and AMED. Searches were conducted in September 2017 without a limit on the starting period. The Physiotherapy Evidence Database scale was used to appraise the quality of the included studies. Data from eligible articles were pooled, and meta-analyses were conducted. The quality of evidence was appraised by the Grading of Recommendations, Assessment, Development and Evaluations approach. The registration number for the review on PROSPERO is CRD42017075215.

RESULTS

A total of 911 records were screened, and 3 randomized controlled trials were eligible to be included in this review. There was a significant pooled standardized mean difference in isometric strength (0.93, 95% confidence interval [CI], 0.17-1.68; P = .02) between the experimental and control groups, with a moderate level of heterogeneity.

CONCLUSION

This review suggests that spinal manipulative therapy augments the percentage of change in isometric strength gain among healthy participants when compared to no intervention or sham manipulation. However, the heterogeneity of pooled studies in this review suggests that the results should be interpreted with caution.