Additional Effect of Static Ultrasound and Diadynamic Currents on Myofascial Trigger Points in a Manual Therapy Program for Patients With Chronic Neck Pain: A Randomized Clinical Trial

Goniometry and fleximetry measurements to assess cervical range of motion in individuals with chronic neck pain: a validity and reliability study

PURPOSE

To assess the test-retest and inter-rater reliability of goniometry and fleximetry in measuring cervical range of motion in individuals with chronic neck pain.

METHODS

A reliability study. Thirty individuals with chronic neck pain were selected. Cervical range of motion was measured by goniometry and fleximetry at two time points 7 days apart. To characterize the sample, we used the numerical pain rating scale, Pain-Related Catastrophizing Thoughts Scale, and Neck Disability Index. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimum detectable change (MDC) were calculated. Correlations between goniometry and fleximetry measurements were performed using Spearman's correlation coefficient (rho).

RESULTS

For goniometry, we found excellent test-retest reliability (ICC ≥ 0.986, SEM ≤ 1.89%, MDC ≤ 5.23%) and inter-rater reliability (ICC ≥ 0.947, SEM ≤ 3.91%, MDC ≤ 10.84%). Similarly, we found excellent test-retest reliability (ICC ≥ 0.969, SEM ≤ 2.71%, MDC ≤ 7.52%) and inter-rater reliability (ICC ≥ 0.981, SEM ≤ 1.88%, MDC ≤ 5.20%) for fleximetry. Finally, we observed a strong correlation between the goniometry and the fleximetry for all cervical movements (rho ≥ 0.993).

CONCLUSION

Goniometry and fleximetry measurements are reliable for assessing cervical range of motion in individuals with chronic neck pain.

Additional effect of transcutaneous electrical nerve stimulation in a therapeutic exercise program for sedentary with chronic neck pain: A double-blind randomized controlled trial

PURPOSE

To evaluate the additional effect of high frequency (HF) or low frequency (LF) transcutaneous electrical nerve stimulation (TENS) in a specific therapeutic exercise program for the treatment of patients with chronic neck pain.

METHODS

A randomized controlled trial. Sixty participants of both sexes and with chronic neck pain were randomized into three groups: therapeutic exercise group + placebo TENS (n = 20), therapeutic exercise group + HF TENS (n = 20) and therapeutic exercise group + low TENS frequency (n = 20). The following assessment instruments were used: Numerical Pain Rating Scale, Neck Disability Index, Pain-Related Catastrophizing Thoughts Scale and Tampa Scale for Kinesiophobia. Participants were evaluated before the interventions, after eight treatment sessions and 1 month after the end of treatment. Primary outcome was disability measured after the eight treatment sessions. Secondary outcomes were pain intensity, catastrophizing, and kinesiophobia after eight treatment sessions and pain intensity 4 weeks after the end of the treatment sessions.

RESULTS

The three groups were similar at baseline for personal and clinical characteristics. Regarding the main study analyses, there were no significant (p > 0.05) or clinical (d < 0.80) differences between the groups for the main variable (disability), nor for the secondary variables (pain intensity, catastrophizing and kinesiophobia).

CONCLUSION

HF or LF TENS, compared to placebo TENS, does not provide additional clinical benefits to an exercise program for patients with chronic neck pain.

Comparison of the autonomic nervous system dysfunction between different chronic spine disorders: neck pain versus low back pain

OBJECTIVE

This study aims to compare heart rate variability (HRV) between patients with chronic neck pain and patients with chronic low back pain and to correlate the chronic pain variables with heart rate variability indices.

METHODS

This is a cross-sectional study. We divided the sample into two groups: neck pain (n=30) and low back pain (n=30). We used the Numeric Pain Rating Scale, Neck Disability Index, Roland-Morris Disability Questionnaire, Pain-Related Catastrophizing Thoughts Scale, Tampa Scale of Kinesiophobia, and Pain Self-Efficacy Questionnaire. For heart rate variability analysis, we used the following indices: mean RR, standard deviation of all RR intervals, mean heart rate, root mean square differences of successive RR intervals, triangular index, triangular interpolation of the interval histogram, low-frequency band in arbitrary units and in absolute values, high-frequency band in arbitrary units and in absolute values, standard deviation of the instantaneous beat-to-beat variability (standard deviation 1), long-term standard deviation of continuous RR intervals (standard deviation 2), and Stress Index. We used Student's t-test for comparisons and Spearman's coefficient for correlations.

RESULTS

We observe insignificant values in the differences between the groups. Disability and self-efficacy were correlated with heart rate variability only in patients with chronic neck pain, whereas catastrophizing and kinesiophobia showed greater correlations with heart rate variability in patients with chronic low back pain.

CONCLUSIONS

Autonomic dysfunction of individuals with chronic neck pain, when compared to patients with chronic low back pain, does present insignificant differences.

Fascial Manipulation Method Is Effective in the Treatment of Myofascial Pain, but the Treatment Protocol Matters: A Randomised Control Trial—Preliminary Report

Background: There are many therapeutic methods targeting fascia. However, the only method whose basic assumption is to eliminate the densification of fascia is Fascial Manipulation. Objective: To evaluate the effectiveness of various Fascial Manipulation (FM) protocols in reducing myofascial pain. Design: Randomized control trial. Subjects: A total of 54 individuals, aged 18–29 years, with musculoskeletal pain for at least 1 week. Methods: The patients were divided into four groups subjected to different treatment protocols: group 1—underwent the standard FM treatment protocol (STP), group 2—modified protocol (MTP), group 3—modified protocol 2 (MTP2), and the control group (CG)—did not undergo any therapy. Each protocol involved three treatments at intervals of 7–10 days and a follow-up examination after 30 days. The outcome was pain level measured using the VAS. Results: In the STP, all the measurements showed a significant decrease in pain level—the mean difference was 2.077 after the first treatment, 3.462 after the third treatment and 3.385 in the follow-up. In the MTP, a significant mean difference was noted after the third treatment, 3, and in the follow up, 2.4. In the MTP2, it was noted after the third session, 2, and in the follow up, 2.25. Only the CG group did not display significant changes. Conclusions: FM-based therapy results in pain relief. However, there are differences in the dynamics and durability of the results depending on the chosen protocol.

Measurement properties of the Brazilian version of the Copenhagen Neck Functional Disability Scale in patients with chronic neck pain

OBJECTIVE

To evaluate the measurement properties of the Brazilian version of the Copenhagen Neck Functional Disability Scale (CNFDS) in patients with chronic neck pain.

METHODS

One hundred and five patients were included in the study. The structural validity of the CNFDS was assessed by exploratory and confirmatory factor analysis with the following fit indices: chi-square divided by degrees of freedom (chi-square/df), root mean square error of approximation (RMSEA), comparative fit index (CFI), and Tucker-Lewis index (TLI). To test the construct validity, the CNFDS score was correlated with the Numerical Pain Rating Scale, the Tampa Scale of Kinesiophobia, the Pain-Related Catastrophizing Thoughts Scale, and Neck Disability Index (NDI). A subsample of 43 patients filled the CNFDS at two different times, and test-retest reliability was measured using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimum detectable change (MDC). The internal consistency of the CNFDS was analyzed by Cronbach's alpha.

RESULTS

CNFDS presented a unidimensional structure, with goodness of fit indices: chi-square/df = 1.37, CFI = 0.94, TLI = 0.93, RMSEA = 0.059. The CNFDS showed satisfactory results of reliability (ICC = 0.93) and internal consistency (Cronbach's alpha = 0.84). The SEM was 1.72 and the MDC was 4.76. The CNFDS showed a high correlation with the NDI (rho = 0.718) and a low correlation with the other instruments. There were no floor and ceiling effects.

CONCLUSION

The Brazilian version of the CNFDS with a one-dimensional structure and 15 items has adequate measurement properties.

Transcutaneous electrical stimulation in neck pain: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The objective of this systematic review was to investigate the effectiveness of electrical stimulation (ES) for neck pain (NP).

DATABASES AND DATA TREATMENT

The databases CINAHL, Embase, MEDLINE (via OVID), PEDro and Web of Science were searched, with no date restrictions. Two independent reviewers selected randomized controlled trials (RCTs) reporting pain, range of motion or psychosocial factors in people with NP, in which ES was applied. Methodological quality was assessed using the PEDro scale. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to evaluate the quality of evidence. Thirty studies met eligibility criteria.

RESULTS

Main results showed evidence of moderate quality that ES combined with other intervention significantly decreases the pain intensity compared to other intervention immediately post-treatment and at short-term follow-up; evidence of low quality showed significant effects of ES combined with other intervention in decreasing neck disability compared to other intervention immediately post-treatment; evidence of very-low quality that ES increased the pressure pain threshold compared to placebo immediately post-treatment and that ES + other intervention also increased the pressure pain threshold compared to other intervention at short-term follow-up.

CONCLUSIONS

ES combined with other intervention seems to be useful to relieve pain and to improve disability in people with NP, however, more studies are needed.

SIGNIFICANCE

Electrical stimulation seems to be effective for improving pain intensity, immediately post-treatment in people with neck pain, mainly as an adjunct therapeutic modality. Nevertheless, high-quality RCTs are still needed to investigate the efficacy of electrical stimulation in neck pain.

Less is More: Five-item Neck Disability Index to Assess Chronic Neck Pain Patients in Brazil

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

The aim of this study was to assess the structural validity of the Brazilian version of the Neck Disability Index (NDI) in patients with chronic neck pain.

SUMMARY OF BACKGROUND DATA

NDI is widely used in clinical and scientific contexts, although its structure has not been evaluated in the Brazilian version.

METHODS

Native Brazilian Portuguese speakers, aged ≥18 years, with neck pain complaint of at least 3 months, and minimal pain rating of 3 points at rest or during neck movements were included. Exploratory factorial analysis (EFA) and confirmatory factorial analysis (CFA) were used. In EFA, the adequacy of the model was assessed using Bartlett test of sphericity and Kaiser-Meyer-Olkin test. In CFA, the goodness-of-fit was assessed by the indices: root mean square error of approximation with 90% of confidence interval, comparative fit index, Tucker-Lewis Index, standardized root mean square residual, and χ2/degree of freedom. Akaike information criterion (AIC) and Bayesian information criterion (BIC) were considered to compare the models.

RESULTS

Two hundred fifty-four participants with chronic neck pain were included. The NDI model with one domain and five items presented the most adequate goodness-of-fit indexes and the lowest values of AIC and BIC, when compared with models with one domain and 10, eight, or seven items, and with the model with two domains and 10 items.

CONCLUSION

In the Brazilian context, the NDI version with one domain and five items (personal care, concentration, work, driving, and recreation) presents the best structure according to the factorial analysis.Level of Evidence: 5.

Therapeutic Ultrasound for Pain Management in Chronic Low Back Pain and Chronic Neck Pain: A Systematic Review

BACKGROUND

Low back pain (LBP) and neck pain are major causes of pain and disability that are experienced across all ages. The primary goals of treatment are to improve patient function and facilitate a return to the patient's desired level of daily activity. Therapeutic ultrasound is a noninvasive modality widely utilized in the management of musculoskeletal disorders, but there continues to be controversy regarding its use due to insufficient evidence of effectiveness. The objective of this systematic review was to evaluate the effectiveness of therapeutic ultrasound in the management of patients with chronic LBP and neck pain.

METHODS

Using PRISMA guidelines, a search of the PubMed and CENTRAL (The Cochrane Library) databases was performed to retrieve randomized controlled trials (RCTs) that evaluated therapeutic ultrasound in patients with chronic LBP or neck pain.

RESULTS

The search strategy identified 10 trials that met the criteria for inclusion. Three studies in LBP reported that both therapeutic and sham (placebo) ultrasound provided significant improvement in pain intensity. In each of these studies, ultrasound was found to be more effective than placebo when using only one of several validated instruments to measure pain. Three of the four studies on neck pain demonstrated significant pain relief with ultrasound in combination with other treatment modalities. However, only one of these studies demonstrated that the use of ultrasound was the cause of the statistically significant improvement in pain intensity.

CONCLUSIONS

Therapeutic ultrasound is frequently used in the treatment of LBP and neck pain and is often combined with other physiotherapeutic modalities. However, given the paucity of trials and conflicting results, we cannot recommend the use of monotherapeutic ultrasound for chronic LBP or neck pain. It does seem that ultrasound may be considered as part of a physical modality treatment plan that may be potentially helpful for short-term pain relief; however, it is undetermined which modality may be superior. In both pain syndromes, further trials are needed to define the true effect of low-intensity ultrasound therapy for axial back pain. No conclusive recommendations may be made for optimal settings or session duration.

Sensory, Motor, and Psychosocial Characteristics of Individuals With Chronic Neck Pain: A Case-Control Study

OBJECTIVE

Given the complex and unclear etiology of neck pain, it is important to understand the differences in central sensitization as well as psychosocial factors in individuals with chronic neck pain and healthy controls. The purpose of this study was to benchmark differences in central sensitization, psychosocial factors, and range of motion between people with nonspecific chronic neck pain and healthy controls and to analyze the correlation between pain intensity, neck disability, and psychosocial factors in people with chronic neck pain.

METHODS

Thirty individuals with chronic neck pain and 30 healthy controls were included in this case-control study. Outcome measures were as follows: central sensitization (pressure pain threshold, temporal summation, and conditioned pain modulation), psychosocial factors (depressive symptoms, pain catastrophizing, and quality of life), and active cervical range of motion.

RESULTS

People with neck pain had lower local pressure pain threshold, a decrease in conditioned pain modulation, more depressive symptoms, greater pain catastrophizing, lower quality of life, and reduced range of motion for neck rotation when compared with healthy controls. In people with neck pain, moderate correlations were observed between pain intensity and quality of life (ρ = -0.479), disability and pain catastrophizing (ρ = 0.379), and disability and quality of life (ρ = -0.456).

CONCLUSIONS

People with neck pain have local hyperalgesia, impaired conditioning pain modulation, depressive symptoms, pain catastrophizing, low quality of life, and reduced active range of motion during neck rotation, which should be taken into account during assessment and treatment.

IMPACT

This study shows that important outcomes, such as central sensitization and psychosocial factors, should be considered during assessment and treatment of individuals with nonspecific chronic neck pain. In addition, pain intensity and neck disability are correlated with psychosocial factors.

Effect of Therapeutic Ultrasound for Neck Pain: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the effects and safety of therapeutic ultrasound in patients with neck pain.

DATA SOURCES

The PubMed, EMBASE, CENTRAL, and Physiotherapy Evidence databases were searched for articles published before December 1, 2020.

STUDY SELECTION

Randomized controlled trials that compared the effects of therapeutic ultrasound on neck pain were included in this review. The included studies compared therapeutic ultrasound plus other treatments with the other treatments alone or compared therapeutic ultrasound with sham or no treatment. Outcome measures involved the effects on pain, disability, and quality of life. Other treatments included all nonultrasonic therapies (eg, various exercises, massage, electrotherapy).

DATA EXTRACTION

Data on the study population, therapeutic ultrasound intervention, combined intervention, outcome measures, and follow-up were extracted.

DATA SYNTHESIS

Twelve randomized controlled trials (705 patients) fulfilled the inclusion criteria. Seven studies compared therapeutic ultrasound plus other treatments vs the other treatments alone (449 patients). Therapeutic ultrasound yielded additional benefits for pain, but there was high heterogeneity and we could not draw a clear conclusion. Ultrasound did not have a better effect on disability or quality of life when it was combined with other treatments. Five studies compared therapeutic ultrasound with sham or no treatment (256 patients), and the pooled data showed that therapeutic ultrasound significantly reduced pain intensity. No adverse events of therapeutic ultrasound were reported in the included studies.

CONCLUSIONS

Therapeutic ultrasound may reduce the intensity of pain more than sham or no treatment, and it is a safe treatment. Whether therapeutic ultrasound in combination with other conventional treatments produced additional benefits on pain intensity, disability, or quality of life is not clear. The randomized trials included in this review had different levels of quality and high heterogeneity. A large trial using a valid methodology is warranted.

Criteria Used for the Diagnosis of Myofascial Trigger Points in Clinical Trials on Physical Therapy: Updated Systematic Review

OBJECTIVE

The objective of this study was to conduct an updated systematic review of diagnostic criteria for myofascial trigger points (MTrPs) used in clinical trials of physical therapy interventions from 2007 to 2019.

METHODS

MEDLINE and Physiotherapy Evidence Database (PEDro) were searched using the following MeSH keywords: "trigger points," "trigger point," "myofascial trigger point," "myofascial trigger points," "myofascial pain," and "myofascial pain syndrome." The MeSH keywords were combined by using Boolean operators "OR"/"AND." All physiotherapy clinical trials including patients with musculoskeletal conditions characterized by at least 1 active MTrP or latent MTrP in any body area were selected. We pooled data from an individual criterion and criteria combinations used to diagnose MTrPs. The protocol was developed in accordance with the PRISMA-P guidelines.

RESULTS

Of 478 possibly relevant publications, 198 met the inclusion criteria. Of these 198 studies, 129 studies (65.1%) stated specifically the diagnostic criteria used for MTrPs in the main text, 56 studies (28.3%) failed to report any method whereby MTrP was diagnosed, and 13 studies (6.6%) adopted expert-based definitions for MTrPs without specification. Of 129 studies, the 6 criteria applied most commonly were: "spot tenderness" (n=125, 96.9%), "referred pain" (95, 73.6%), "local twitch response" (63, 48.8%), pain recognition (59, 45.7%), limited range of motion" (29, 22.5%), and "jump sign" (10, 7.8%). Twenty-three combinations of diagnostic criteria were identified. The most frequently used combination was "spot tenderness," "referred pain," and "local twitch response" (n=28 studies, 22%).

CONCLUSIONS

A number of the included studies failed in properly reporting the MTrP diagnostic criteria. Moreover, high variability in the use of MTrP diagnostic was also observed. Spot tenderness, referred pain, and local twitch response were the 3 most popular criteria (and the most frequently used combination). A lack of transparency in the reporting of MTrP diagnostic criteria is present in the literature.

REGISTRY

This systematic review was registered under the Centre for Reviews and Dissemination, PROSPERO number: CRD42018087420.

The effect of ultrasound or phonophoresis as an adjuvant treatment for non-specific neck pain: systematic review of randomised controlled trials

OBJECTIVE

To determine the effectiveness of ultrasound/phonophoresis as an adjuvant to exercise or manual therapy for the improvement of patient-centred outcomes in adults with non-specific neck pain (NSNP).

METHODS

Seven electronic databases were systematically searched up to September 2020. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to judge the Quality of Evidence (QoE).

RESULTS

Six studies involving 249 participants were included. The QoE was very low GRADE. Phonophoresis with capsaicin plus exercise improved pain at immediate post-treatment (MD: -3.30 [-4.05, -2.55]) but not with diclofenac sodium plus exercise as compared to exercise. Continuous ultrasound (CUS) plus exercise improved pain and pressure pain threshold (PPT) at immediate post-treatment (pain: MD: -3.42 [-4.08, -2.7]); (PPT: MD: 0.91 [0.68, 1.14]) and at intermediate-term as compared to exercise. CUS or high power pain threshold (HPPT) ultrasound plus manual therapy and exercise showed no benefit for pain reduction (MD: -0.75 [-2.08, 0.58]) did not improve function/disability (MD: -1.05 [-4.27, 2.17]) at immediate or short-term as compared to manual therapy and exercise.

CONCLUSIONS

Due to high risk of bias, inconsistency, and indirectness the QoE is very low in support of benefit of ultrasound/phonophoresis as an adjuvant treatment for NSNP.Implication for rehabilitationDue to high risk of bias, inconsistency, and indirectness the quality of evidence (QoE) is very low in support of benefit of adding ultrasound or phonophoresis to exercise or manual therapy for pain reduction or improvement in function/disability for those with sub-acute and chronic myofascial associated neck pain. However, our confidence in the findings is very low and conclusions are likely to change as more evidences emerges.Clinicians using ultrasound therapy as an adjuvant intervention for management of chronic myofascial associated neck pain should carefully consider the available evidence on ultrasound, including the benefits and costs involved.

Effectiveness of Hydrogalvanic Bath on Improving Pain, Disability, and Quality of Life in Individuals with Chronic Nonspecific Neck Pain: A Randomized Controlled Trial

Background

Neck pain is one of the world's leading factors in years lived with disability. Ambiguity in the effect of electrotherapy modalities for the treatment of chronic nonspecific neck pains (CNSNP) needs to be examined further. This study sought to elucidate the effectiveness of hydrogalvanic bath on improving pain, disability, and quality of life among individuals with CNSNP.

Methods

Thirty-four individuals with a diagnosis of CNSNP were selected through convenient sampling and randomly divided into two groups by block randomization. The control group treatment underwent low Transcutaneous Electrical Nerve Stimulation (TENS) and exercise, and the experimental group was subjected to hydrogalvanic bath therapy (HGBT) and exercise. Individuals were evaluated for pain using a visual analog scale (VAS), disability with the Neck Disability Index (NDI), and quality of life with Short Form-36 (SF-36). These measures were applied at baseline and after 12 weeks of treatment.

Results

The pretreatment and posttreatment results for VAS, NDI, and SF-36 were compared for both control and experimental groups. We found that all the three variables showed significant differences between the two time points with p < 0.05 in both the groups but the experimental group improvements were more significant than the control group with p < 0.05.

Conclusion

Twelve weeks of low TENS or HGBT along with exercises can decrease pain and neck disability and increase the quality of life in individuals with CNSNP. However, HGBT along with exercise has superior effects relative to low TENS along with exercise. This randomized controlled trial was registered in the International Standard Randomized Controlled Trials Number-ISRCTN29695190 and registered on 05/02/2020. This study is a retrospective registration.

Effects of joint mobilisation on clinical manifestations of sympathetic nervous system activity: a systematic review and meta-analysis

BACKGROUND

A potential mechanism of action of manual therapy is the activation of a sympathetic-excitatory response.

OBJECTIVE

To evaluate the effects of joint mobilisation on changes in clinical manifestations of sympathetic nervous system activity.

DATA SOURCES

MEDLINE, EMBASE, AMED, CINAHL, EBSCO, PubMed, PEDro, Cochrane Collaboration Trials Register, Cochrane Database of Systematic Reviews and SCOPUS databases.

STUDY SELECTION

Randomised controlled trials that compared a mobilisation technique applied to the spine or the extremities with a control or placebo.

DATA EXTRACTION AND DATA SYNTHESIS

Human studies collecting data on skin conductance or skin temperature were used. Data were extracted by two reviewers. Risk of bias was assessed using the Cochrane guidelines, and quality of evidence was assessed using the GRADE approach. Standardised mean differences (SMD) and random effects were calculated.

RESULTS

Eighteen studies were included in the review and 17 were included in the meta-analysis. The meta-analysis found a significant increase in skin conductance [SMD 1.21, 95% confidence interval (CI) 0.88 to 1.53, n=269] and a decrease in temperature (SMD 0.92, 95% CI -1.47 to -0.37, n=128) after mobilisation compared with the control group. An increase in skin conductance (SMD 0.73, 95% CI 0.51 to 0.96, n=293) and a decrease in temperature (SMD -0.50, 95% CI -0.82 to -0.18, n=134) were seen after mobilisation compared with placebo. The risk of bias was generally low, but the heterogenicity of the results downgraded the level of evidence.

LIMITATIONS

Most trials (14/18) were conducted on asymptomatic healthy subjects.

CONCLUSION

There is moderate evidence suggesting a sympatho-excitatory effect of joint mobilisation. Systematic Review Registration Number PROSPERO CRD42018089991.

Evaluation of Postural Balance and Articular Mobility of the Lower Limbs in Chronic Neck Pain Patients by Means of Low-Cost Clinical Tests

OBJECTIVE

The purpose of this study was to correlate measurements of chronic neck pain with the balance and mobility of the lower limbs and to compare these variables between individuals with chronic neck pain and asymptomatic participants.

METHODS

This was a blinded cross-sectional study. Participants with chronic neck pain (n = 30) and asymptomatic participants (n = 30) were included in the study. To measure pain in the neck region, the Numeric Rating Scale, Neck Disability Index, and Pain-Related Catastrophizing Thoughts Scale were applied. The assessment of postural balance and mobility of the lower limbs was made using the Timed Up and Go Test, Functional Reach Test (FRT), Lateral Reach Test, and 30-second Chair Stand Test.

RESULTS

No statistically (P > .05) and clinically (d < 0.50) significant differences were identified for the variables tested here. However, regarding the correlations, a significant association was identified only between the intensity of pain during cervical movements and FRT (r = -0.312).

CONCLUSION

Young adults with chronic neck pain present changes in static balance measured by means of the FRT; that is, the higher the intensity of pain, the lower the anteroposterior excursion of the body during the execution of the test.

Location of Reference Electrode Does Not Interfere on Electromyographic Parameters in the Domains of Time and Frequency

There is currently little information on the positioning of reference electrode (RE). It is generally accepted that it must be positioned on electrically neutral tissues, such as tendons or bony prominences. The objective of this study is to analyze the characteristics of the electromyographic signal (EMG) for different positions of RE as well as at different levels of muscle contraction. Signals from the brachial biceps and triceps were recorded from 18 healthy women (BMI: 21.20 kg/m² ± 1.72; mean age: 21.94 ± 1.98 years old) during 100 and 50% maximum flexion voluntary isometric contractions, as well as at rest. For each situation, the RE was randomly positioned in 4 different locations: a) homolateral acromion; b) homolateral brachial biceps; c) styloid process of the contralateral ulna; and d) lateral malleolus of the contralateral ankle. For statistical analysis, Shapiro-Wilk and Kruskal-Wallis tests were used, followed by Dunn's post-hoc test, at a significance level of 5% (p < 0.05). RMS, normalized RMS, PSD, median frequency and levels of energy at 60 Hz, 120 Hz and 180 Hz were assessed for the different sites of RE. The results show that the positioning of the RE on the four experimental locations did not change important features of the electromyographic signals in the time and frequency domains, for the three levels of isometric contractions studied. Such findings compel us to re-think the current trend regarding the RE position followed by the great majority of the researches in areas such as physical therapy.