Search

Conservative management of lumbar radiculopathy (LR) is the first treatment option. To date, systematic reviews and clinical practice guidelines have not considered the most appropriate timing of management. This study aimed to establish consensus on effective conservative treatment modalities across different stages (i.e., acute, sub-acute, or chronic) of LR. Through an iterative multistage Delphi process, experts rated agreement with proposed treatment modalities across stages of LR and could suggest additional treatment modalities. The agreement was measured using a 5-point Likert scale. Descriptive statistics were used to measure agreement (median, interquartile ranges, and percentage of agreement). Consensus criteria were defined a priori for each round. Fourteen panelists produced a consensus list of effective treatment modalities across stages of LR. Acute stage management should focus on providing patients with information about the condition including pain education, individualized physical activity, and directional preference exercises, supported with NSAIDs. In the sub-acute stage, strength training and neurodynamic mobilization could be added and transforaminal/epidural injections considered. In the chronic stage, spinal manipulative therapy, specific exercise, and function-specific physical training should be combined with individualized vocational, ergonomic and postural advice. Experts agree effectiveness of interventions differs through the evolution of LR. To date clinical guideline for conservative management of lumbar radiculopathy do not consider the evolution of the condition. Acute stage management of lumbar radiculopathy should focus on providing information about the condition and support individualized physical activity with pain medication. Sub-acute management should add neurodynamic mobilization to strength training, while transforaminal and/or epidural injections could be considered. Chronic stage management should consider spinal manipulative therapy and focus on restoring personalized functional capacity. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Pain experimentally induced in the lumbar region results in task-dependent adaptation of muscle activity and in a reduction of lumbar range of motion. Experimental pain models are frequently used to understand the influence of pain on the control of human movement. In this systematic review, we assessed the effects of experimentally induced pain in the lumbar region of healthy individuals on trunk muscle activity and spine kinematics. Databases were searched from inception up to January 31, 2022. In total, 26 studies using either hypertonic saline injection (n = 19), heat thermal stimulation (n = 3), nociceptive electrical stimulation (n = 3), or capsaicin (n = 1) were included. The identified adaptations were task dependent, and their heterogeneity was partially explained by the experimental pain model adopted. Meta-analyses revealed an increase of erector spinae activity (standardized mean difference = 0.71, 95% confidence interval [CI] = 0.22-1.19) during full trunk flexion and delayed onset of transversus abdominis to postural perturbation tasks (mean difference = 25.2 ms, 95% CI = 4.09-46.30) in the presence of pain. Low quality of evidence supported an increase in the activity of the superficial lumbar muscles during locomotion and during voluntary trunk movements during painful conditions. By contrast, activity of erector spinae, deep multifidus, and transversus abdominis was reduced during postural perturbation tasks. Reduced range of motion of the lumbar spine in the presence of pain was supported by low quality of evidence. Given the agreement between our findings and the adaptations observed in clinical populations, the use of experimental pain models may help to better understand the mechanisms underlying motor adaptations to low back pain. [ABSTRACT FROM AUTHOR]

Coronavirus disease (Covid-19) is a highly infectious disease caused by the SARS-CoV-2 virus and is associated with a decrease of respiratory, physical, and psychological function, subsequently affecting quality of life. The aim of the present pilot study was to use ultrasound imaging (USI) to evaluate and compare the thickness of the diaphragm and abdominal muscles between individuals recently diagnosed with moderate Covid-19 infection and healthy individuals. Methods: A cross-sectional observational pilot study was performed. A total sample of 24 participants were recruited from a private medical center (Madrid, Spain): Covid-19 (n = 12) and healthy controls (n = 12). The external oblique (EO), internal oblique (IO), transversus abdominis (TrA), rectus abdominis (RA), interrecti distance (IRD) and diaphragm thickness were assessed using USI during inspiration, expiration and during contraction. Results: USI measurements of the thickness of EO, IO, TrA, RA, IRD and the diaphragm did not differ significantly between groups during inspiration, expiration or during contraction (all P > 0.05). Conclusions: These preliminary results suggest that the morphology of the abdominal muscles and diaphragm is not altered in people with a recent history of moderate Covid-19 infection. [ABSTRACT FROM AUTHOR]

Background: To evaluate whether digital pain extent is associated with an array of psychological factors such as optimism, pessimism, expectations of recovery, pain acceptance, and pain self-efficacy beliefs as well as to analyse the association between digital pain extent and pain intensity and pain-related disability in people with chronic musculoskeletal pain. Methods: A descriptive cross-sectional study conducted in a primary health care setting was carried out including 186 individuals with chronic musculoskeletal pain. Patient-reported outcomes were used to assess psychological factors, pain intensity, and pain-related disability. Digital pain extent was obtained from pain drawings shaded using a tablet and analysed using novel customized software. Multiple linear regression models were conducted to evaluate the association between digital pain extent and the aforementioned variables. Results: Digital pain extent was statistically significantly associated with pain intensity. However, digital pain extent was not associated with any psychological measure nor with pain-related disability. Discussion: The results did not support an association between digital pain extent and psychological measures. [ABSTRACT FROM AUTHOR]

Background: To evaluate whether digital pain extent is associated with an array of psychological factors such as optimism, pessimism, expectations of recovery, pain acceptance, and pain self-efficacy beliefs as well as to analyse the association between digital pain extent and pain intensity and pain-related disability in people with chronic musculoskeletal pain.Methods: A descriptive cross-sectional study conducted in a primary health care setting was carried out including 186 individuals with chronic musculoskeletal pain. Patient-reported outcomes were used to assess psychological factors, pain intensity, and pain-related disability. Digital pain extent was obtained from pain drawings shaded using a tablet and analysed using novel customized software. Multiple linear regression models were conducted to evaluate the association between digital pain extent and the aforementioned variables.Results: Digital pain extent was statistically significantly associated with pain intensity. However, digital pain extent was not associated with any psychological measure nor with pain-related disability.Discussion: The results did not support an association between digital pain extent and psychological measures. [ABSTRACT FROM AUTHOR]

Objective: Specific neck exercises (SNE) targeting deep cervical flexors and extensors are commonly used for the treatment of nonspecific neck pain (NSNP). However, whether SNE are more effective than alternative exercise interventions (AEI) remains unclear. Furthermore, it has been postulated that SNE may be most effective when they are tailored and targeted to patients with evidence of motor control dysfunction, yet this notion also remains unproven. The objectives of this study were to compare the effectiveness of SNE with that of AEI for reducing pain and disability in people with NSNP and to assess whether the effectiveness of SNE is increased when the exercises are tailored and provided to patients with evidence of motor control dysfunction. Methods: For this systematic review with meta-analysis, Medline, Web of Science, Scopus, and Physiotherapy Evidence Database were searched. Eligibility criteria included randomized controlled trials evaluating the effectiveness of SNE against that of AEI in people with NSNP. Meta-analysis included subgroup analyses to determine the effect of exercise tailoring and participant selection criteria on the effectiveness of SNE. Results: Twelve studies were included. Meta-analysis revealed greater effectiveness of SNE in the short to medium term for reducing pain (pooled standardized mean difference [SMD] = −0.41; 95% CI = −0.76 to −0.06; P =.02) and disability (pooled SMD = −0.41; 95% CI = −0.78 to −0.04; P =.03) but no differences in the long term for pain (pooled SMD = −1.30; 95% CI = −3.35 to 0.75; P =.21) and disability (pooled SMD = −1.81; 95% CI = −4.29 to 0.67; P =.15), although evidence was limited for the latter. The effectiveness of SNE was not superior in studies that included only participants with motor control dysfunction or when exercises were tailored to each participant. Overall, the studies were of low quality. Grading of Recommendations Assessment, Development and Evaluation revealed low certainty, serious risk of bias, and inconsistency of findings for short- to medium-term effects and very low certainty, serious risk of bias, and very serious inconsistency for long-term effects. Conclusion: The preferential use of SNE may be recommended to achieve better short- to medium-term outcomes, although the low quality of evidence affects the certainty of these findings. Currently used strategies for selecting patients and tailoring SNE are not supported by the evidence and therefore cannot be recommended for clinical practice. Impact: SNE are more effective than AEI for reducing pain and disability in patients with NSNP in the short to medium term, but overall evidence is of low quality, affecting the certainty of the findings. Tests of muscle dysfunction (mostly the craniocervical flexion test) currently used in studies to select patients and tailor SNE do not result in greater effectiveness of these exercises. Lay Summary: Evidence suggests SNE are more effective than other forms of exercise, although evidence is overall of low quality. Use of the craniocervical flexion test in isolation to select participants and/or tailor SNE cannot be recommended. [ABSTRACT FROM AUTHOR]

Background: Numerous studies report changes in neuromuscular control in people with low back pain (LBP). However, the relationship between pain and altered neuromuscular control is challenging to unravel given the heterogeneity that exists in clinical populations. One approach commonly adopted to overcome this issue is the use of experimental pain models, but it is currently unclear if the effects of experimental pain are consistent between studies. Therefore, this planned study will systematically evaluate and summarise the effect of experimentally induced pain in the lumbar region on neuromuscular control at sites both locally and remote to the low back. Methods: This protocol has been developed following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). MEDLINE, EMBASE, CINAHL, ZETOC, Web of Science, and grey literature will be searched up to August 31, 2021. Screening processes (title/abstract and full-text), data extraction, and risk of bias assessment will be conducted by two independent reviewers. Studies investigating the effects of exogenous pain models delivered to the low back region on neuromuscular control in healthy individuals will be included. Muscle activity and body kinematics will be the outcomes of interest. The comparisons of interest will be between baseline or control conditions and the experimental pain condition, as well as between the experimental pain and post-pain conditions. Randomised crossover and non-randomised studies of interventions will be included and their risk of bias will be evaluated with the Cochrane Risk-of-Bias tool or with the Risk Of Bias In Non-randomised Studies of Interventions tool, respectively. A random-effect meta-analysis will be conducted for quantitative synthesis when clinical and methodological consistency is ensured. Quality of evidence will be evaluated using the Grading of Recommendations, Assessment, Development and Evaluation guidelines. Discussion: The current review will provide new insights to understand if and what neuromuscular adaptations are caused by pain experimentally induced in the lumbar region. Our findings will reveal which experimental pain model is able to better reproduce adaptations similar to those identified in people with low back pain, possibly contributing to improving our understanding of motor adaptation to low back pain in the long term. Systematic review registration: PROSPERO CRD42020220130 [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether a set of pre-accident demographic, accident-related, post-accident treatment and psychosocial factors assessed in people with acute/subacute whiplash-associated disorders (WAD) mediate the association between pain intensity and: (1) pain interference and (2) expectations of recovery, using Bayesian networks (BNs) analyses. This study also explored the potential mediating pathways (if any) between different psychosocial factors. Methods: This was a cross-sectional study conducted on a sample of 173 participants with acute/subacute WAD. Pain intensity, pain interference, pessimism, expectations of recovery, pain catastrophizing, and self-efficacy beliefs were assessed. BN analyses were conducted to analyse the mediating effects of psychological factors on the association between pain intensity and pain-related outcomes. Results: The results revealed that self-efficacy beliefs partially mediated the association between pain intensity and pain interference. Kinesiophobia partially mediated the association between self-efficacy and pain catastrophizing. Psychological factors did not mediate the association between pain intensity and expectations of recovery. Conclusion: These results indicate that individuals with acute/subacute WAD may present with lesser pain interference associated with a determined pain intensity value when they show greater self-efficacy beliefs. As the cross-sectional nature of this study limits firm conclusions on the causal impact, researchers are encouraged to investigate the role that patient's self-efficacy beliefs play in the transition to chronic WAD via longitudinal study designs. [ABSTRACT FROM AUTHOR]

Background: Previous systematic reviews have identified the benefits of exercise for chronic neck pain on subjective reports of pain, but not with objective measures such as quantitative sensory testing (QST). A systematic review was conducted to identify the effects of neck specific exercise on QST measures in adults with chronic neck pain to synthesise existing literature and provide clinical recommendations. Methods: The study protocol was registered prospectively with PROSPERO (PROSPERO CRD42021297383). For both randomised and non-randomised trials, the following databases and trial registries were searched: AMED, CINAHL, Embase, Google Scholar, Medline, PEDro, PubMed, Scopus, SPORTDiscus, Science Citation Index and Social Science Citation Index from Web of Science Core Collection, clinicaltrials.gov, GreyOpen, and ISRCTN registry. These searches were conducted from inception to February 2022 and were updated until September 2023. Reference lists of eligible studies were screened. Study selection was performed independently by two reviewers, with data extraction and quality appraisal completed by one reviewer and independently ratified by a second reviewer. Due to high heterogeneity, narrative synthesis was performed with results grouped by exercise type. Findings: Three trials were included. Risk of bias was rated as moderate and the certainty of evidence as low or moderate for all studies. All exercise groups demonstrated statistically significant improvement at an intermediate-term follow-up, with progressive resistance training combined with graded physical training demonstrating the highest certainty of evidence. Fixed resistance training demonstrated statistically significant improvement in QST measures at a short-term assessment. Interpretation: Fixed resistance training is effective for short-term changes in pain sensitivity based on low-quality evidence, whilst moderate-quality evidence supports progressive resistance training combined with graded physical training for intermediate-term changes in pain sensitivity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate differences in passive muscular stiffness between the superficial multifidus (SM) and deep multifidus (DM), and to compare their passive and active stiffness in individuals with low back pain (LBP) and asymptomatic individuals. Fifteen LBP individuals and 15 asymptomatic individuals were recruited. Passive stiffness of the SM and DM was measured bilaterally using shear wave elastography (SWE) with participants lying prone. Active stiffness was measured for the SM during trunk extension, and the contraction ratio was calculated. DM displayed higher passive muscular stiffness than SM in both the asymptomatic and LBP groups (14.41 ± 2.62 and 15.40 ± 2.77 kPa respectively; p < 0.001). Individuals with LBP exhibited higher passive muscular stiffness of SM (LBP: 10.15 ± 4.21, asymptomatic: 6.84 ± 1.69 kPa; p < 0.005) and a lower contraction ratio (LBP: 1.54 ± 0.47, asymptomatic: 2.65 ± 1.36 kPa; p < 0.003) compared to the asymptomatic group. The findings support a differentiation in passive muscular stiffness between SM and DM and provide evidence for an alteration in muscular stiffness at rest in individuals with LBP. The lower increase of muscular stiffness with contraction observed for those with LBP may reflect a deficit in activation of the multifidus. [ABSTRACT FROM AUTHOR]

Objective. Our aims were 1) to investigate whether perceived pain extent, assessed from the pain drawing, relates to clinical, psychological, and psychophysical outcomes in women with carpal tunnel syndrome (CTS); 2) to assess differences in pain extent depending on the presence of median or extramedian symptoms; and 3) to investigate differences in pain extent according to severity (minimal, moderate, or severe) or laterality (unilateral or bilateral) of CTS. Methods. One hundred forty (N�0) women with CTS completed pain drawings, which were subsequently digitized, allowing pain extent to be calculated. Clinical features including pain intensity (numerical pain rating scale, 0�) and disability (Boston Carpal Tunnel Questionnaire), psychological features including depression (Beck Depression Inventory), and psychophysical variables (pressure pain and thermal pain thresholds) were assessed. Spearman rho correlation coefficients were used to reveal the correlations between pain extent and other outcomes. Differences in pain extent according to severity (minimal, moderate, severe) or laterality (unilateral, bilateral) and the presence of extramedian symptoms were also evaluated. Results. No significant associations were identified between pain extent and clinical, psychological, or psychophysical outcomes. Women with extramedian symptoms (88%) exhibited a larger (P<0.001) pain extent (total: 24.2%613.5%) than women with median symptoms (12%; total: 12.2%66.9%). Pain extent was not significantly different depending on the severity or laterality of the symptoms. Conclusions. Pain extent in the upper extremity was not associated with clinical, psychological, or psychophysical variables and was not related to the severity or laterality of the symptoms in women with CTS. [ABSTRACT FROM AUTHOR]

Background: Limited knowledge exists on current use of patient reported outcome measures (PROMs) and performance measures for adolescents with idiopathic scoliosis (AIS), as well as health care professionals' (HCPs) perceived barriers and facilitators towards their use. This study's objectives were: 1) to explore current practice of HCPs when assessing outcomes for AIS 2) to understand perceived barriers and facilitators of HCPs to use PROMs 3) to understand perceived barriers and facilitators of HCPs to use performance measures. Methods: A qualitative study recruited a purposive sample of HCPs from a tertiary hospital in the United Kingdom. Mean years of experience managing individuals with AIS was 11.8 years; and included surgeons, physiotherapists and nurses, educated at Bachelor, Masters and Doctoral level. Consent to participate and demographic information were collected in advance of the interviews. In-depth, virtual semi-structured interviews were informed by a topic guide based on current evidence. Interviews of approximately 45 minutes were audio and video recorded and transcribed verbatim alongside written field notes. Data were coded and analysed using inductive thematic analysis, involving researchers with topic and methodological expertise and input from a patient representative. Results: Two themes emerged regarding current practice of using PROMs routine practice and personal evaluations. Four themes emerged as barriers to using PROMs for individuals with AIS: priority and support (e.g., HCPs focus on providing care), practical challenges (e.g., inadequate PROMs), patient-related challenges (e.g., patient preferences) and knowledge, education, and perceived value. Two themes emerged as facilitators: quality existing measure (e.g., sufficient psychometric properties), and priority and support (e.g., research department/culture). Themes for barriers to use performance measures were practicality (e.g., need physical space) and perceived value and knowledge (e.g., PROMs are more important), while the one theme for facilitators was practical consideration (e.g., acceptability). Conclusions: Although HCPs perceived the value of using outcome measures, current practice indicates limited use for individuals with AIS. The findings revealed different barriers and facilitators to implement PROMs in practice. Adopting performance measure are limited due to lack of knowledge and perceived value alongside the practicality, while considering practical factors can improve the use of these measures in practice. [ABSTRACT FROM AUTHOR]

Objective The Patient-Specific Functional Scale (PSFS) is a patient-reported outcome measure used to assess functional limitations. Recently, the PSFS 2.0 was proposed; this instrument includes an inverse numeric rating scale and an additional list of activities that patients can choose. The aim of this study was to assess the test–retest reliability, measurement error, responsiveness, and minimal important change of the PSFS 2.0 when used by patients with nonspecific neck pain. Methods Patients with nonspecific neck pain completed a numeric rating scale, the PSFS 2.0, and the Neck Disability Index at baseline and again after 12 weeks. The Global Perceived Effect (GPE) was also collected at 12 weeks and used as an anchor. Test–retest measurement was assessed by completion of a second PSFS 2.0 after 1 week. Measurement error was calculated using a Bland–Altman plot. The receiver operating characteristic method with the anchor (GPE) functions as the reference standard was used for calculating the minimal important change. Results One hundred patients were included, with 5 lost at follow-up. No floor and ceiling effects were reported. In the test–retest analysis, the mean difference was 0.15 (4.70 at first test and 4.50 at second test). The ICC (mixed models) was 0.95, indicating high agreement (95% CI = 0.92–0.97). For measurement error, the upper and lower limits of agreement were 0.95 and −1.25 points, respectively, with a smallest detectable change of 1.10. The minimal important change was determined to be 2.67 points. The PSFS 2.0 showed satisfactory responsiveness, with an area under the curve of 0.82 (95% CI = 0.70–0.93). There were substantial to high correlations between the change scores of the PSFS 2.0 and the Neck Disability Index and GPE (0.60 and 0.52, respectively; P  < .001). Conclusion The PSFS 2.0 is a reliable and responsive patient-reported outcome measure for use by patients with neck pain. [ABSTRACT FROM AUTHOR]

Background and Aims According to existing literature, musicians are at risk of experiencing a range of painful musculoskeletal conditions. Recently, a novel digital technology was developed to investigate pain location and pain extent. The aim of this study was to describe pain location and pain extent in musicians using a digital method for pain drawing ( PD) analysis. Additionally, the association between PD variables and clinical features were explored in musicians with pain. Methods One hundred and fifty-eight musicians (90 women and 68 men; aged 22.4 ± 3.6 years) were recruited from Swiss and U.K. conservatories. Participants were asked to complete a survey including both background musical information and clinical features, the Quick DASH ( QD) questionnaire, and the digital PDs. Results Of the 158 participants, 126 musicians (79.7%) reported having pain, with higher prevalence in the areas of the neck and shoulders, the lower back, and the right arm. The mean percentage of pain extent was 3.1% ± 6.5%. The mean QD score was higher for musicians with pain than for those without pain. Additionally, the results indicated a positive correlation between the QD score and pain extent, and there were significant correlations between age and pain intensity, as well as between pain extent and pain intensity. Conclusions The high prevalence of pain among musicians has been confirmed using a digital technique for PD acquisition and analysis. In addition, positive correlations between pain extent and upper limb disability have been demonstrated. Our findings highlight the need for effective prevention and treatment strategies for musicians. [ABSTRACT FROM AUTHOR]

Purpose: Using a novel technique of high-density surface EMG decomposition and motor unit (MU) tracking, we compared changes in the properties of vastus medialis and vastus lateralis MU after endurance (END) and high-intensity interval training (HIIT). Methods: Sixteen men were assigned to the END or the HIIT group (n = 8 each) and performed six training sessions for 14 d. Each session consisted of 8-12 x 60-s intervals at 100% peak power output separated by 75 s of recovery (HIIT) or 90-120 min continuous cycling at ~65% ...O2peak (END). Pre- and postintervention, participants performed 1) incremental cycling to determine ...O2peak and peak power output and 2) maximal, submaximal (10%, 30%, 50%, and 70% maximum voluntary contraction [MVC]), and sustained (until task failure at 30% MVC) isometric knee extensions while high-density surface EMG signals were recorded from the vastus medialis and vastus lateralis. EMG signals were decomposed (submaximal contractions) into individual MU by convolutive blind source separation. Finally, MU were tracked across sessions by semiblind source separation. Results: After training, END and HIIT improved ...O2peak similarly (by 5.0% and 6.7%, respectively). The HIIT group showed enhanced maximal knee extension torque by ~7% (P = 0.02) and was accompanied by an increase in discharge rate for high-threshold MU (≥50% knee extension MVC) (P < 0.05). By contrast, the END group increased their time to task failure by ~17% but showed no change in MU discharge rates (P > 0.05). Conclusions: HIIT and END induce different adjustments in MU discharge rate despite similar improvements in cardiopulmonary fitness. Moreover, the changes induced by HIIT are specific for high-threshold MU. For the first time, we show that HIIT and END induce specific neuromuscular adaptations, possibly related to differences in exercise load intensity and training volume. [ABSTRACT FROM AUTHOR]

Background Pain drawings ( PD) are frequently used in research to illustrate the pain response to pain provocation tests. However, there is a lack of data on the reliability in defining the extent and location of pain. We investigated the test-retest reliability in reporting an acute painful sensation induced by a pain provocation test using a novel approach for PD acquisition and analysis in healthy volunteers. Methods Forty healthy volunteers participated. Each participant underwent 2 upper limb neurodynamic tests 1 ( ULNT1), once to the point of pain onset ( PO) and once until the point of submaximal pain ( SP). After each ULNT1, participants completed 2 consecutive PD with an interval of 1 minute. Custom software was used to quantify the pain extent and analyze the pain overlap. The test-retest reliability of pain extent was examined using Intraclass Correlation Coefficient ( ICC 2,1) and Bland-Altman plots. Pain location reliability was examined using the Jaccard similarity coefficient ( JSC). Results The ICC values for PO and SP were 0.98 (95% CI: 0.96-0.99) and 0.97 (95% CI: 0.95-0.98), respectively. The mean difference and 95% limits of agreement (± 1.96 SD) in the Bland-Altman plots were 14 pixels (−1080;1110) for PO, and 145 (−1610;1900) for SP. The median JSCs (Q1;Q3) were 0.73 (0.64;0.80) for PO and 0.76 (0.65;0.79) for SP. Conclusions Pain drawings is a reliable instrument to investigate pain extent and pain location in healthy individuals experiencing an acute painful sensation induced by a pain provocation test. [ABSTRACT FROM AUTHOR]

Objective To describe the effects of therapy on masseter activity and chewing kinematic in patients with unilateral posterior crossbite (UPC). Design Fifty children (age: mean ± SD: 9.1 ± 2.3 years) with UPC (34 on the right side, 16 on the left side) and twenty children (age: 9.5 ± 2.6 years) with normal occlusion were selected for the study. The mandibular motion and the muscular activity during chewing soft and hard boli were simultaneously recorded, before and after correction with function generating bite, after a mean treatment time of 7.3 ± 2.4 months plus the retention time of 5–6 months. The percentage of reverse cycles and the percent difference between ipsilateral and contralateral peaks of the masseter electromyography envelopes were computed. Results Before therapy, the percentage of reverse cycles during chewing on the crossbite side was greater in patients than in controls (P < 0.001) and significantly reduced after therapy (P < 0.001) towards the reference normal value (soft bolus; pre: 57 ± 30%, post:12 ± 17%; hard bolus; pre: 65 ± 34%, post: 12 ± 13%; reference value: soft bolus 4 ± 2%, hard bolus 5 ± 3%). Before therapy the percent difference between electromyography envelope peaks in patients was lower than in controls (P < 0.01) and significantly increased after therapy (P < 0.05) becoming similar to the reference normal value. Conclusions The correction induced a normal-like coordination of masseter muscles activity together with a significant reduction of the reverse chewing patterns. The previous altered muscular activation corresponded to the altered kinematics of reverse chewing cycles that might be considered a useful indicator of the severity of the masticatory function involvement. [ABSTRACT FROM AUTHOR]

This study evaluates and compares the effects of strength and endurance training on motor unit discharge rate variability and force steadiness of knee extensor muscles. Thirty sedentary healthy men (age, 26.0±3.8yrs) were randomly assigned to strength training, endurance training or a control group. Conventional endurance and strength training was performed 3days per week, over a period of 6weeks. Maximum voluntary contraction (MVC), time to task failure (at 30% MVC), coefficient of variation (CoV) of force and of the discharges rates of motor units from the vastus medialis obliquus and vastus lateralis were determined as subjects performed 20% and 30% MVC knee extension contractions before and after training. CoV of motor unit discharges rates was significantly reduced for both muscles following strength training (P<0.001), but did not change in the endurance (P=0.875) or control group (P=0.995). CoV of force was reduced after the strength training intervention only (P<0.01). Strength training, but not endurance training, reduces motor unit discharge rate variability and enhances force steadiness of the knee extensors. These results provide new insights into the neuromuscular adaptations that occur with different training methods. [ABSTRACT FROM AUTHOR]

Eccentric exercise is characterized by initial unfavorable effects such as subcellular muscle damage, pain, reduced fiber excitability, and initial muscle weakness. However, stretch combined with overload, as in eccentric contractions, is an effective stimulus for inducing physiological and neural adaptations to training. Eccentric exercise-induced adaptations include muscle hypertrophy, increased cortical activity, and changes in motor unit behavior, all of which contribute to improved muscle function. In this brief review, neuromuscular adaptations to different forms of exercise are reviewed, the positive training effects of eccentric exercise are presented, and the implications for training are considered. [ABSTRACT FROM AUTHOR]

Introduction: Scoliosis Research Society-22 revised (SRS-22r) is the common questionnaire used to evaluate health related quality of life (HRQOL) for young people with adolescent idiopathic scoliosis (AIS). The aim of this study is to evaluate its content validity for this population. Methods: In-depth semi-structured interviews were conducted with a purposive sample of young people with AIS (Cobb angle ≥25˚, aged 10–18 years). Concept elicitation was used to evaluate the influence of AIS on participants' HRQOL. Participant information sheets and consent/assent forms were age relevant. Topic guide was informed by the SRS-22r and existing evidence. Interviews were audio and video recorded, transcribed verbatim, coded, and analysed using thematic analysis. Derived themes/codes were compared with SRS-22r contents (domains/items). Results: Eleven participants (mean age 14.9 years [SD = 1.8]; 8 female) were recruited. The mean curve size was 47.5° [SD = 18°] and participants had been managed via different approaches. Four main themes emerged with associated subthemes: 1) Physical effects related to physical symptoms (back hurt, stiffness) and body asymmetry (uneven shoulders), 2) Activity-related effects showed impact on mobility (sitting for long periods), self-care (dressing), and school activities (focus during lessons), 3) Psychological effects revealed emotional (feel worried), mental (sleep quality), and body image effects (hide back from others), 4) Social effects (participation in school and leisure activities), and school, friends and mental health support. A weak association was found between items of the SRS-22r and the identified codes. Conclusion: The SRS-22r does not adequately capture important concepts that relate to HRQOL of adolescents with AIS. These findings support revision of the SRS-22r, or the development of a new patient reported outcome measure to evaluate HRQOL of adolescents with AIS. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the activation of the sternocleidomastoid (SCM) and splenius capitis (SC) muscles in response to unanticipated, full body perturbations in individuals with chronic neck pain (NP) and age-matched healthy controls (HC). Individuals with NP had a history of NP for 8.9 ± 7.8 years, rated the intensity of NP as 4.2 ± 2.0 (score out of 10), and scored 15.3 ± 6.5 on the Neck Disability Index. Participants stood on a moveable platform during which 32 randomized postural perturbations (eight repetitions of four perturbation types: 8 cm forward slide (FS), 8 cm backward slides, 10° forward tilt, and 10° backward tilt) with varying inter-perturbation time intervals were performed over a period of 5 min. Bilateral surface electromyography (EMG) from the SCM and SC was recorded, and the onset time and the average rectified value of the EMG signal was determined for epochs of 100 ms; starting 100 ms prior to and 500 ms after the perturbation onset. Individuals with NP, as compared to HC, demonstrated delayed onset times and reduced EMG amplitude of the SCM and SC muscles in response to all postural perturbations. Such findings were most pronounced following the FS postural perturbation (healthy vs. NP for SCM 83.3 ± 8.0 vs. 86.3 ± 4.4 and SC 75.6 ± 3.5 vs. 89.3 ± 4.2), which was also associated with the greatest change (expressed in % relative to baseline) in EMG amplitude (healthy vs. NP for SCM 206.6 ± 50.4 vs. 115.9 ± 15.7 and SC 83.4 ± 19.2 vs. 69.2 ± 10.9) across all postural perturbations types. Individuals with NP display altered neural control of the neck musculature in response to rapid, unanticipated full body postural perturbations. Although the relative timing of neck musculature activity in individuals with NP appears to be intact, simultaneous co-activation of the neck musculature emerges for unanticipated anterior-posterior postural perturbations. [ABSTRACT FROM AUTHOR]

This study investigated change in the distribution of lumbar erector spinae muscle activity and pressure pain sensitivity across the low back in individuals with low back pain (LBP) and healthy controls. Surface electromyographic (EMG) signals were recorded from multiple locations over the lumbar erector spinae muscle with a 13×5 grid of electrodes from 19 people with chronic nonspecific LBP and 17 control subjects as they performed a repetitive lifting task. The EMG root mean square (RMS) was computed for each location of the grid to form a map of the EMG amplitude distribution. Pressure pain thresholds (PPT) were recorded before and after the lifting task over a similar area of the back. For the control subjects, the EMG RMS progressively increased more in the caudal region of the lumbar erector spinae during the repetitive task, resulting in a shift in the distribution of muscle activity. In contrast, the distribution of muscle activity remained unaltered in the LBP group despite an overall increase in EMG amplitude. PPT was lower in the LBP group after completion of the repetitive task compared to baseline (average across all locations: pre: 268.0±165.9kPa; post: 242.0±166.7kPa), whereas no change in PPT over time was observed for the control group (320.1±162.1kPa; post: 322.0±179.5kPa). The results demonstrate that LBP alters the normal adaptation of lumbar erector spinae muscle activity to exercise, which occurs in the presence of exercise-induced hyperalgesia. Reduced variability of muscle activity may have important implications for the provocation and recurrence of LBP due to repetitive tasks. [ABSTRACT FROM AUTHOR]

Muscle pain induces a complex reorganization of the motor strategy which cannot be fully explained by current theories. We tested the hypothesis that the neural control of muscles during reaching in the presence of nociceptive input is determined by a reorganization of muscle synergies with respect to control conditions. Muscle pain was induced by injection of hypertonic saline into the anterior deltoid muscle of eight men. Electromyographic (EMG) signals were recorded from 12 upper limb muscles as subjects performed a reaching task before (baseline) and after the injection of hypertonic (pain) saline, and after the pain sensation vanished. The EMG envelopes were factorized in muscle synergies, and activation signals extracted for each condition. Nociceptive stimulation resulted in a complex muscle reorganization without changes in the kinematic output. The anterior deltoid muscle activity decreased in all subjects while the changes in other muscles were subject specific. Three synergies sufficed to describe the EMG patterns in each condition, suggesting that reaching movements remain modular in the presence of experimental pain. Muscle reorganization in all subjects was accompanied by a change in the activation signals compatible with a change in the central drive to muscles. One, two or three synergies were shared between the baseline and painful conditions, depending on the subject. These results indicate that nociceptive stimulation may induce a reorganization of modular control in reaching. We speculate that such reorganization may be due to the recruitment of synergies specific to the painful condition. [ABSTRACT FROM AUTHOR]

Background Appropriate timing of activity of the vastus medialis obliqus (VMO) and vastus lateralis (VL) muscles is a key factor for proper tracking of the patella in the trochlear groove during knee extension. This study investigates the relative timing of activation of the VMO and VL muscles during unexpected perturbations performed before and after eccentric exercise. Methods Surface electromyography signals were recorded from the VMO and VL muscles of the right leg in 11 healthy men during rapid postural perturbations performed at baseline, immediately after eccentric exercise of the quadriceps, and at 24 and 48 h after exercise. Participants stood on a moveable platform during which eight randomised postural perturbations were performed (4 repetitions of 2 perturbation types: 8 cm forward slides, 8 cm backward slides). Results Before the eccentric exercise, the onset of VMO activity was significantly earlier than the VL muscle (average for both forward and backward perturbations: VMO 39.0±7.1 ms; VL 43.7±7.9 ms). However, the onset of VMO activity was significantly later compared with VL muscle immediately after eccentric exercise and this remained 24 and 48 h after eccentric exercise (average across all postexercise sessions and perturbation directions: VMO 72.3±11.1 ms; VL 56.0±8.2 ms; p<0.05). Conclusions The onset of VMO--VL activity in response to rapid destabilising perturbations is altered immediately after eccentric exercise and during eccentric exercise-induced muscle soreness up to 48 h later. These observations may help explain the high prevalence of knee disorders after high intensity eccentric exercise. [ABSTRACT FROM AUTHOR]

The purpose of this narrative review is to provide a critical reflection of how analytical machine learning approaches could provide the platform to harness variability of patient presentation to enhance clinical prediction. The review includes a summary of current knowledge on the physiological adaptations present in people with spinal pain. We discuss how contemporary evidence highlights the importance of not relying on single features when characterizing patients given the variability of physiological adaptations present in people with spinal pain. The advantages and disadvantages of current analytical strategies in contemporary basic science and epidemiological research are reviewed and we consider how analytical machine learning approaches could provide the platform to harness the variability of patient presentations to enhance clinical prediction of pain persistence or recurrence. We propose that machine learning techniques can be leveraged to translate a potentially heterogeneous set of variables into clinically useful information with the potential to enhance patient management. [ABSTRACT FROM AUTHOR]

Abstract: Due to the variations in morphological and architectural characteristics of fibers within a skeletal muscle, regions of a muscle may be differently affected by eccentric exercise. Although eccentric exercise may be beneficial for increasing muscle mass and can be beneficial for the treatment of tendinopathies, the non-uniform effect of eccentric exercise results in regional muscle damage and as a consequence, non-uniform changes in muscle activation. This regional muscle weakness can contribute to muscle strength imbalances and may potentially alter the load distribution on joint structures, increasing the risk of injury. In this brief review, the non-uniform effects of eccentric exercise are reviewed and their implications for training and sport are considered. [Copyright &y& Elsevier]

The article reports on research which was conducted to investigate the effect strength and endurance training on muscle fiber membrane properties and discharge rates of low-threshold motor units of the vasti muscles during fatiguing contractions. Researchers evaluated 25 sedentary healthy men who were randomly assigned to one of three groups: strength training, endurance training, or a control group. They found that short-term strength and endurance training induces alterations of the electrophysiological membrane properties of the muscle fiber and that endurance training lowers the rate of decline of motor unit conduction velocity during sustained contractions more than strength training.

Abstract: This study proposes a method for estimating force loss during fatiguing maximal isokinetic knee extension contractions using a set of features from surface EMG signals recorded from multiple locations over the quadriceps muscle. Nine healthy participants performed fatiguing tests which consisted of 50 and 75 isokinetic leg extensions at a speed of 30°/s and 80°/s in two experimental sessions on different days. The set of data recorded from one of the experimental sessions (at both velocities) was used to train a multi-layer perceptron neural network to associate force loss (direct measure of fatigue) to EMG features. The data from the other session (obtained from the tests at both velocities) were used for testing the neural network performance. The proposed method was compared with a previous approach for the assessment of fatigue (Mapping Index, MI) using a signal to noise metrics computed on the estimated trend of fatigue. The signal to noise ratio obtained with the proposed approach was greater (8.83±1.07) than that obtained with the MI (5.67±1.17) (P <0.05) when the subjects were analyzed individually and when the network was trained over the entire subject group (8.07 vs. 4.42). In conclusion, the proposed approach allows estimation of force loss during maximal dynamic knee extensions from surface EMG signals with greater accuracy than previous methods. [Copyright &y& Elsevier]

Abstract: The study compared the distribution of electromyographic (EMG) signal amplitude in the upper trapezius muscle in 10 women with fibromyalgia and in 10 healthy women before and after experimentally-induced muscle pain. Surface EMG signals were recorded over the right upper trapezius muscle with a 10×5 grid of electrodes during 90° shoulder abduction sustained for 60s. The control subjects repeated the abduction task following injections of isotonic and hypertonic (painful) saline into the upper trapezius muscle. The EMG amplitude was computed for each electrode pair and provided a topographical map of the distribution of muscle activity. The pain level rated by the patients at the beginning of the sustained contraction was 5.9±1.5. The peak pain intensity for the control group following the injection of hypertonic saline was 6.0±1.6. During the sustained contractions, the EMG amplitude increased relatively more in the cranial than caudal region of the upper trapezius muscle for the control subjects (shift in the distribution of EMG amplitude: 2.3±1.3mm; P <0.01). The patient group showed lower average EMG amplitude than the controls during the contraction (P <0.05) and did not show different changes in EMG amplitude between different regions of the upper trapezius. A similar behavior was observed for the control group following injection of hypertonic saline. The results indicate that muscle pain prevents the adaptation of upper trapezius activity during sustained contractions as observed in non-painful conditions, which may induce overuse of similar muscle compartments with fatigue. [Copyright &y& Elsevier]

Abstract: Objective: To compare the behavior of sternocleidomastoid motor units of patients with chronic neck pain and healthy controls. Methods: Nine women (age, 40.4±3.5yr) with chronic neck pain and nine age- and gender-matched healthy controls participated. Surface and intramuscular EMG were recorded from the sternocleidomastoid muscle bilaterally as subjects performed isometric contractions of 10-s duration in the horizontal plane at a force of 15N in eight directions (0–360°; 45° intervals) and isometric contractions at 15 and 30N force with continuous change in force direction in the range 0–360°. Motor unit behavior was monitored during the 10-s contractions and the subsequent resting periods. Results: The mean motor unit discharge rate depended on the direction of force in the control subjects (P <0.05) but not in the patients. Moreover, in three of the nine patients, but in none of the controls, single motor unit activity continued for 8.1±6.1s upon completion of the contraction. The surface EMG amplitude during the circular contraction at 15N was greater for the patients (43.5±54.2μV) compared to controls (16.9±14.9μV; P <0.05). Conclusions: The modulation in discharge rate of individual motor units with force direction is reduced in the sternocleidomastoid muscle in patients with neck pain, with some patients showing prolonged motor unit activity when they were instructed to rest. Significance: These observations suggest that chronic neck pain affects the change in neural drive to muscles with force direction. [Copyright &y& Elsevier]

The article focuses on one study which investigates the action potential propagation velocity in individual motor units before and after the performance of eccentric exercise. 10 healthy men were recruited for the study and were asked to perform the eccentric exercise which consists of a series of four sets of 25 repetitions with three-minute rest between each set. Sensory assessment of muscle pain, EMG recordings, data analysis, statistical analysis were the conducted after the performance. After data interpretation, it was revealed that the electrophysiological membrane properties of muscle fibers are altered by exercise-induced muscle fiber damage.

Abstract: This study investigated whether pain-induced changes in cervical muscle activation affect myoelectric manifestations of cervical muscle fatigue. Surface EMG signals were detected from the sternocleidomastoid and splenius capitis muscles bilaterally from 14 healthy subjects during 20-s cervical flexion contractions at 25% of the maximal force. Measurements were performed before and after the injection of 0.5ml of hypertonic (painful) or isotonic (control) saline into either the sternocleidomastoid or splenius capitis in two experimental sessions. EMG average rectified value and mean power spectral frequency were estimated throughout the sustained contraction. Sternocleidomastoid or splenius capitis muscle pain resulted in lower sternocleidomastoid EMG average rectified value on the side of pain (P <0.01). However, changes over time of sternocleidomastoid EMG average rectified value and mean frequency (myoelectric manifestations of fatigue) during sustained flexion were not changed during muscle pain. These results demonstrate that pain-induced modifications of cervical muscle activity do not change myoelectric manifestations of fatigue. This finding has implications for interpreting the mechanisms underlying greater cervical muscle fatigue in people with neck pain disorders. [Copyright &y& Elsevier]

Abstract: This study examined gender differences in the effect of experimental muscle pain on changes in the relative activation of regions of the upper trapezius muscle during a sustained contraction. Surface electromyographic (EMG) signals were recorded from multiple locations over the upper trapezius muscle with a 10×5 grid of electrodes from nine women and nine men during 90° shoulder abduction sustained for 60s. Measurements were performed before and after the injection of 0.4ml hypertonic (painful) and isotonic (control) saline into the cranial region of the upper trapezius muscle. The EMG root mean square (RMS) was computed for each location of the grid to form a map of the EMG amplitude distribution. The peak pain intensity following the injection of hypertonic saline was greater for women (numerical rating scale 0–10: women 6.0±2.1, men 4.2±0.9; P <0.01). For both genders, upper trapezius RMS averaged across the grid decreased following the injection of hypertonic saline (P <0.0001). Moreover, there was a relatively larger pain-induced decrease in RMS in the cranial region compared to the caudal region of the muscle for both genders. During the non-painful sustained contractions, the EMG RMS progressively increased more in the cranial than the caudal region, for both men and women, due to fatigue. This mechanism was maintained in men but not in women during the painful condition. The results demonstrate that muscle pain alters the normal adaptation of upper trapezius muscle activity to fatigue in women but not in men. [Copyright &y& Elsevier]

Measurements of muscle-fiber conduction velocity during voluntary contractions have been used in the diagnosis of neuromuscular diseases. However, the velocity of propagation of action potentials depends on the interspike interval of activation due to the velocity recovery function (VRF) of muscle fibers. The comparison of muscle-fiber conduction velocity estimates between individuals may thus be influenced by differences in motor unit discharge rate. This study investigates action potential properties of motor units of the sternocleidomastoid muscle during voluntary modulation of discharge rate with the purpose of assessing the effect of the VRF on motor unit properties in voluntary contractions. Nineteen healthy men trained to control a target motor unit with feedback of surface multichannel electromyographic (EMG) signals. The subjects performed three 30-s contractions of cervical flexion/rotation modulating the discharge rate of the target motor unit from 6.6 ± 1.6 pps to 28.0 ± 6.4 pps. Action potential conduction velocity was correlated to instantaneous discharge rate ( R = 0.38 ± 0.21). Action potential conduction velocity, peak-to-peak amplitude, and duration varied between minimum and maximum discharge rate ( P < 0.01; percent change 12.3 ± 5.0, −11.8 ± 9.9, and −12.9 ± 7.3). Thus, the properties of surface motor unit action potentials vary with modulation of discharge rate. This has implications for the use of conduction velocity values measured during voluntary contractions to differentiate patient populations from healthy individuals and for the development of normative data. Muscle Nerve, 2008 [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this brief review is to present evidence from experimental and clinical neck pain studies of pain-induced neuromuscular adaptations. It has been shown that clinical neck pain is associated with a substantial reorganization in the control strategies of cervical muscles during static and dynamic tasks. Experimental neck pain models allow local elicitation of nociceptive afferents, mimicking the sensory aspects of clinical pain, without major changes in muscle properties. These models may help understand the physiological mechanisms underlying the observations from clinical neck pain studies. The knowledge obtained from the interpretation of clinical findings with experimental pain models has relevance for the development of therapeutic interventions for the rehabilitation of patients with neck pain disorders. [Copyright &y& Elsevier]

The article focuses on the study on applying novel topographical mapping techniques to investigate sensory and EMG manifestations of delayed-onset muscle soreness (DOMS) in multiple locations of the quadriceps. According to the author, the bipolar surface EMG signals are recorded from 11 healthy men with 15 pairs of electrodes locations located at 10, 20 and 30 % of the distance from the medial, superior and lateral border of the patella to the anterior superior iliac spine. He emphasized that the novel topographical mapping of both surface EMG and PPT of the quadriceps showed site-dependent effects of eccentric exercise.

This study compared fatigue and the spatial distribution of upper trapezius electromyographic (EMG) amplitude during a 6-min constant force shoulder elevation task at 20% of the maximal voluntary contraction force (MVC) (constant force) and during the same task interrupted by brief (2 s) periodic increases in force to 25% MVC every 30 s (variable force). Surface EMG signals were recorded with a 13 × 5 grid of electrodes from the upper trapezius muscle of nine healthy subjects. The centroid (center of activity) of the EMG root mean square map was computed to assess changes over time in the spatial distribution of EMG amplitude. MVC force decreased by (mean ± SD) 9.0 ± 3.9% after the constant force task ( P < 0.05) but was unchanged following the variable force contraction. The centroid of EMG amplitude shifted in the cranial direction across the duration of the variable force contraction ( P < 0.05) but not during the constant force contraction (shift of 2.9 ± 2.3 mm and 1.4 ± 1.1 mm, respectively). The results demonstrate that periodic increases in force during a sustained contraction enhance the modifications in spatial distribution of upper trapezius EMG amplitude and reduce fatigue compared to a constant force contraction performed at a lower average load. The change in spatial distribution of EMG amplitude over time during a sustained contraction may reflect a mechanism to counteract fatigue during prolonged muscle activity. [ABSTRACT FROM AUTHOR]

Background and Purpose Poor sitting posture has been implicated in the development and perpetuation of neck pain symptoms. This study had 2 purposes: (1) to compare change in cervical and thoracic posture during a distracting task between subjects with chronic neck pain and control subjects and (2) to compare the effects of 2 different neck exercise regimens on the ability of people with neck pain to maintain an upright cervical and thoracic posture during this task. Subjects Fifty-eight subjects with chronic, nonsevere neck pain and 10 control subjects participated in the study. Method Change in cervical and thoracic posture from an upright posture was measured every 2 minutes during a 10-minute computer task. Following baseline measurements, the subjects with neck pain were randomized into one of two 6-week exercise intervention groups: a group that received training of the craniocervical flexor muscles or a group that received endurance-strength training of the cervical flexor muscles. The primary outcomes following intervention were changes in the angle of cervical and thoracic posture during the computer task. Results Subjects with neck pain demonstrated a change in cervical angle across the duration of the task (mean=4.4°; 95% confidence interval [CI]=3.3-5.4), consistent with a more forward head posture. No significant difference was observed for the change in cervical angle across the duration of the task for the control group subjects (mean=2.2°; 95% CI=1.0-3.4). Following intervention, the craniocervical flexor training group demonstrated a significant reduction in the change of cervical angle across the duration of the computer task. Discussion and Conclusion This study showed that people with chronic neck pain demonstrate a reduced ability to maintain an upright posture when distracted. Following intervention with an exercise program targeted at training the craniocervical flexor muscles, subjects with neck pain demonstrated an improved ability to maintain a neutral cervical posture during prolonged sitting. [ABSTRACT FROM AUTHOR]

The aim of the study was to examine the effect of experimental unilateral upper trapezius muscle pain on the relative activation of trapezius muscle subdivisions bilaterally during repetitive movement of the upper limb. Surface EMG signals were detected from nine healthy subjects from the upper, middle and lower divisions of trapezius during a repetitive bilateral shoulder flexion task. Measurements were performed before and after injection of 0.5 ml hypertonic (pain condition) and isotonic (control) saline into the upper division of the right trapezius muscle in two experimental sessions. On the painful side, upper trapezius showed decreased EMG amplitude (average rectified value, ARV) and lower trapezius increased ARV throughout the entire task following the injection of hypertonic saline (40.0 ± 22.2 vs. 26.0 ± 17.4 μV, and 12.5 ± 7.6 vs. 25.6 ± 14.8 μV, respectively, at the beginning of the contraction). On the side contralateral to pain, greater estimates of ARV were identified for the upper division of trapezius as the task progressed (37.4 ± 20.2 vs. 52.7 ± 28.4 μV, at the end of the contraction). Muscle fiber conduction velocity did not change with pain in all three divisions of the right trapezius muscle. The results suggest that local elicitation of nociceptive afferents in the upper division of the trapezius induces reorganization in the coordinated activity of the three subdivisions of the trapezius in repetitive dynamic tasks. [ABSTRACT FROM AUTHOR]

This study compared the effects of conventional proprioceptive training and craniocervical flexion (C-CF) training on cervical joint position error (JPE) in people with persistent neck pain. The aim was to evaluate whether proprioceptive training was superior in improving proprioceptive acuity compared to another form of exercise, which has been shown to be effective in reducing neck pain. This may help to differentiate the mechanisms of effect of such interventions. Sixty-four female subjects with persistent neck pain and deficits in JPE were randomized into two exercise groups: proprioceptive training or C-CF training. Exercise regimes were conducted over a 6-week period, and all patients received personal instruction by an experienced physiotherapist once per week. A significant pre- to postintervention decrease in JPE, neck pain intensity, and perceived disability was identified for both the proprioceptive training group ( p < 0.001) and the C-CF training group ( p < 0.05). Patients who participated in the proprioceptive training demonstrated a greater reduction in JPE from right rotation compared to the C-CF training group ( p < 0.05). No other significant differences were observed between the two groups. The results demonstrated that both proprioceptive training and C-CF training have a demonstrable benefit on impaired cervical JPE in people with neck pain, with marginally more benefit gained from proprioceptive training. The results suggest that improved proprioceptive acuity following intervention with either exercise protocol may occur through an improved quality of cervical afferent input or by addressing input through direct training of relocation sense. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 2007 [ABSTRACT FROM AUTHOR]

Abstract: The deep cervical flexor (DCF) muscles are considered to be of substantial clinical importance in the management of neck pain. While conventional cervical flexion (CF) dynamometry methods have been used frequently to assess the capacity of the cervical flexor muscles, it has been suggested that cranio-cervical flexion (CCF) methods may provide a more specific test of DCF muscle performance. This study compared the activation of the deep and superficial cervical flexor muscles between tests of isometric cranio-cervical flexion (CCF) and conventional cervical flexion (CF) dynamometry. Normalised root-mean-square values were recorded for the deep cervical flexor (DCF), sternocleidomastoid (SCM), anterior scalene (AS), and sternohyoid (SH) muscles during isometric CCF and CF tests at maximal voluntary contraction (MVC), 50% MVC, and 20% MVC in ten healthy volunteers. The results demonstrated significantly greater electromyography (EMG) amplitude for the SCM (P <.001–.002) and AS (P <.001–.001) muscles in the CF test conditions (MVC, 20%MVC, and 50%MVC) compared to CCF test conditions. Moreover, the SH muscle demonstrated significantly greater EMG amplitude during CF compared to CCF but only in the 50% MVC and 20% MVC conditions (P =.007 and .02 respectively). These results demonstrate that dynamometry tests of CF result in greater activity of the superficial cervical flexor muscles compared to tests of CCF. As a result, CCF dynamometry may provide a more specific method to assess and retrain DCF muscle performance, compared to conventional CF in which superficial muscle activity may mask impaired performance of the DCF muscles. [Copyright &y& Elsevier]

Abstract: The purpose of the study was to examine the temporal and spatial correlation between estimates of trapezius muscle fiber conduction velocity (CV) and surface EMG instantaneous mean power spectral frequency (iMPF) during dynamic movement of the upper limb. Surface EMG signals were detected from the upper division of the trapezius muscle in 13 healthy volunteers using linear arrays of eight electrodes at three locations in the cephalad–caudal direction. Subjects were asked to tap with their hands in a cyclic manner between targets positioned mid thigh and 120° of shoulder flexion, to the beat of a metronome set at 88 beats per minute for 5min. Muscle fiber CV and iMPF were estimated for each cycle at the time instant corresponding to 90° of shoulder flexion. Non-significant correlations were identified between CV and iMPF initial values (R 2 =0.03–0.01), rate of change over time (R 2 =0.10–0.004) and normalized rate of change (R 2 =0.12–0.01) at all three locations on the upper trapezius muscle. These results demonstrate that both spatial and temporal variations in trapezius muscle fiber CV are not predicted by EMG spectral analysis during dynamic movement of the upper limb. This finding suggests that spectral analysis cannot be used to infer changes in the spatial and temporal behavior of muscle fiber CV during dynamic tasks. [Copyright &y& Elsevier]

Abstract: The purpose of this study was to compare average muscle fiber conduction velocity (CV) and its changes over time in the upper trapezius muscle during a repetitive upper limb task in people with chronic neck pain and in healthy controls. Surface EMG signals were detected bilaterally from the upper trapezius muscle of 19 patients and nine healthy controls using linear adhesive arrays of four electrodes. Subjects were asked to tap their hands in a cyclic manner between targets positioned mid-thigh and 120° of shoulder flexion, to the beat of a metronome set at 88 beats/min for up to 5min. Muscle fiber CV and instantaneous mean power spectral frequency were estimated for each cycle at the time instant corresponding to 90° of shoulder flexion. Average muscle fiber CV of the upper trapezius muscle was higher in people with chronic neck pain (mean±SE, 4.8±0.1m/s) than in control subjects (4.4±0.1m/s; P&#60;0.05). Furthermore, the exercise-induced decrease in CV over time was enhanced in the patient group (P&#60;0.05). It was concluded that membrane muscle fiber properties of the upper trapezius and their changes over time during dynamic contraction of the upper limb are different in a sample of people with chronic neck pain with respect to controls. This may be associated with the histological and morphological changes, which have previously been identified in people with pain over the trapezius muscle. [Copyright &y& Elsevier]

Background and Purpose. This study evaluated an electromyographic technique for the measurement of muscle activity of the deep cervical flexor (DCF) muscles. Electromyographic signals were detected from the DCF, sternocleidomastoid (SCM), and anterior scalene (AS) muscles during performance of the craniocervical flexion (CCF) test, which involves performing 5 stages of increasing craniocervical flexion range of motion--the anatomical action of the DCF muscles. Subjects. Ten volunteers without known pathology or impairment participated in this study. Methods. Root-mean-square (RIMS) values were calculated for the DCF, SCM, and AS muscles during performance of the CCF test. Myoelectric signals were recorded from the DCF muscles using bipolar electrodes placed over the posterior oropharyngeal wall. Reliability estimates of normalized RMS values were obtained by evaluating intraclass correlation coefficients and the normalized standard error of the mean (SEM). Results. A linear relationship was evident between the amplitude of DCF muscle activity and the incremental stages of the CCF test (F=239.04, df=36, P<.0001). Normalized SEMs in the range 6.7% to 10.3% were obtained for the normalized RMS values for the DCF muscles, providing evidence of reliability for these variables. Discussion and Conclusion. This approach for obtaining a direct measure of the DCF muscles, which differs from those previously used, may be useful for the examination of these muscles in future electromyographic applications. [ABSTRACT FROM AUTHOR]

Motor learning underpins successful motor skill acquisition. Although it is well known that pain changes the way we move, it's impact on motor learning is less clear. The aim of this systematic review was to synthesize evidence on the impact of experimental and clinical pain on task performance and activity-dependent plasticity measures across learning and explore these findings in relation to different pain and motor learning paradigms. Five databases were searched: Web of Science, Scopus, MEDLINE, Embase and CINAHL. Two reviewers independently screened the studies, extracted data, and assessed risk of bias using the Cochrane ROB2 and ROBIN-I. The overall strength of evidence was rated using the GRADE guidelines. Due to the heterogeneity of study methodologies a narrative synthesis was employed. Twenty studies were included in the review: fifteen experimental pain and five clinical pain studies, covering multiple motor paradigms. GRADE scores for all outcome measures suggested limited confidence in the reported effect for experimental pain and clinical pain, on motor learning. There was no impact of pain on any of the task performance measures following acquisition except for 'accuracy' during a tongue protrusion visuomotor task and 'timing of errors' during a motor adaptation locomotion task. Task performance measures at retention, and activity dependent measures at both acquisition and retention showed conflicting results. This review delivers a detailed synthesis of research studies exploring the impact of pain on motor learning. This is despite the challenges provided by the heterogeneity of motor learning paradigms, outcome measures and pain paradigms employed in these studies. The results highlight important questions for further research with the goal of strengthening the confidence of findings in this area. [ABSTRACT FROM AUTHOR]

Sensitization mechanisms are thought to play a role in the perception of pain in people with cluster headache. No study has investigated the relation between the spatial extent of pain in cluster headache and measures of sensitization or other clinical features. Our aim was to investigate if the size of the painful area in people with cluster headache relates to widespread pressure sensitivity, headache features, and psychological outcomes. Forty men with episodic cluster headache reported their symptoms on a digital body chart and pain extent was calculated. Pressure pain thresholds were assessed locally over the temporalis muscle and the C5-C6 joint and at a remote site over the tibialis anterior to assess widespread pressure sensitivity. Clinical features of headache attacks, and anxiety/depressive levels were also assessed. Patients were assessed during a period of remission 6 months after their last pain attack and after treatment discontinuation. Thirty-two (80%) and thirty (75%) patients reported their headaches in the orbital and the frontal areas, respectively. No significant associations (rho values ranging from −0.228 to 0.187, P values ranging from 0.157 to 0.861) were found between pain extent and pressure pain thresholds in trigeminal, extra-trigeminal, and distant pain-free areas, headache clinical features, and anxiety and depressive levels. Pain extent in the trigemino-cervical area was not related to the degree of pressure pain sensitivity or headache features in men with episodic cluster headache during a period of remission. [ABSTRACT FROM AUTHOR]

The diversity in electromyography (EMG) techniques and their reporting present significant challenges across multiple disciplines in research and clinical practice, where EMG is commonly used. To address these challenges and augment the reproducibility and interpretation of studies using EMG, the Consensus for Experimental Design in Electromyography (CEDE) project has developed a checklist (CEDE-Check) to assist researchers to thoroughly report their EMG methodologies. Development involved a multi-stage Delphi process with seventeen EMG experts from various disciplines. After two rounds, consensus was achieved. The final CEDE-Check consists of forty items that address four critical areas that demand precise reporting when EMG is employed: the task investigated, electrode placement, recording electrode characteristics, and acquisition and pre-processing of EMG signals. This checklist aims to guide researchers to accurately report and critically appraise EMG studies, thereby promoting a standardised critical evaluation, and greater scientific rigor in research that uses EMG signals. This approach not only aims to facilitate interpretation of study results and comparisons between studies, but it is also expected to contribute to advancing research quality and facilitate clinical and other practical applications of knowledge generated through the use of EMG. [ABSTRACT FROM AUTHOR]

Exercise is recommended for office workers with neck pain. However, recent reviews evaluated the effectiveness of workplace interventions only. To evaluate the effect of exercise on pain, disability, and quality of life (QoL) in office workers with chronic neck pain. Systematic review with meta-analysis. Electronic databases were searched from inception to April 30, 2022, to identify studies in which participants were adults aged ≥18 years undergoing any form of neck exercises (e.g., strengthening, motor control) or physical activity (e.g., aerobic exercise) performed for a minimum of two-weeks without any other additional treatment besides advice or education. Two reviewers independently screened papers and determined the certainty of the evidence. Eight randomised controlled trials met the eligibility criteria. Seven studies reported a significant decrease in Visual Analogue Scale (VAS) scores for neck pain intensity and five studies reported a significant decrease in Neck Disability Index (NDI) scores following strengthening exercises. Only one study assessed the effect of strengthening exercises on QoL and reported no significant effect. All eight included studies had a high risk of bias and the overall certainty of evidence was low. Meta-analyses demonstrated a significant decrease of neck pain intensity and disability for strengthening exercises compared to a control (p < 0.01). There is low certainty of evidence that strengthening of the neck, shoulder and scapular musculature is effective at reducing neck pain and disability in office workers. Further research evaluating the effect of exercise on QoL is required. [ABSTRACT FROM AUTHOR]

Introduction: People with chronic neck pain (CNP) commonly exhibit a range of physical impairments including cervical proprioceptive deficits. Assessing proprioception using a head mounted laser to assess joint position error (JPE) is a reliable and valid measure. However, the responsiveness of this measure has not been assessed. Objective: To assess the responsiveness of the measure of cervical JPE after a 4-week home-based neck proprioceptive training intervention in people with CNP. Design: An observational study to assess the responsiveness of the measure of cervical JPE. Methods: The JPE test was assessed in people with CNP before and after 4 weeks of neck proprioception training. JPE was assessed as participants performed neck joint position sense tests for flexion, extension, right rotation, and left rotation in sitting and standing which were performed in a random order. Both the absolute and constant JPE were assessed. The intervention consisted of neck repositioning exercises as well as movement sense exercises. Cohen's d effect size was used to assess the internal responsiveness of the JPE test. The Pearson's correlation was used to assess the change of scores of the laser pointer and measures from inertial measurement units (IMUs) (external responsiveness). Results: After 4 weeks of proprioception training, JPE assessed in sitting reduced from 2.69◦-3.57◦ to 1.88◦-1.98◦ for flexion, extension, and right rotation with large effect sizes (Cohen's d range: 1.25–2.00). For left rotation, JPE reduced from 3.23◦ to 1.9◦, and the effect size was close to being large (Cohen's d: 0.79). When assessed in standing, JPE reduced from 3.49◦-4.52◦ to 1.5◦-2.33◦ with large effect sizes (Cohen's d range: 0.89–1.25) for flexion, extension, right rotation, and left rotation. Large effect sizes were not observed for the constant JPE when assessed in either sitting or standing. The assessment of the external responsiveness revealed weak correlations between the change of scores obtained from the laser pointer and the IMUs for all movements, apart from the constant JPE in sitting for left rotation, which showed a strong correlation (r = 0.7). Conclusion: The results of this study showed that the measure of the JPE has sufficient internal responsiveness, however, the external responsiveness was inadequate. Further research is advised. [ABSTRACT FROM AUTHOR]

Posture analysis is important in musculoskeletal disorder prevention but relies on subjective assessment. This study investigates the applicability and reliability of a machine learning (ML) pose estimation model for the human posture assessment, while also exploring the underlying structure of the data through principal component and cluster analyses. A cohort of 200 healthy individuals with a mean age of 24.4 ± 4.2 years was photographed from the frontal, dorsal, and lateral views. We used Student's t-test and Cohen's effect size (d) to identify gender-specific postural differences and used the Intraclass Correlation Coefficient (ICC) to assess the reliability of this method. Our findings demonstrate distinct sex differences in shoulder adduction angle (men: 16.1° ± 1.9°, women: 14.1° ± 1.5°, d = 1.14) and hip adduction angle (men: 9.9° ± 2.2°, women: 6.7° ± 1.5°, d = 1.67), with no significant differences in horizontal inclinations. ICC analysis, with the highest value of 0.95, confirms the reliability of the approach. Principal component and clustering analyses revealed potential new patterns in postural analysis such as significant differences in shoulder–hip distance, highlighting the potential of unsupervised ML for objective posture analysis, offering a promising non-invasive method for rapid, reliable screening in physical therapy, ergonomics, and sports. [ABSTRACT FROM AUTHOR]