Fatigue changes neck muscle control and deteriorates postural stability during arm movement perturbations in patients with chronic neck pain

Results of neck-specific exercise for altered postural sway in individuals with chronic whiplash-associated disorders: a longitudinal case-control study

Postural sway has not been investigated before or after a neck exercise intervention in individuals with chronic whiplash-associated disorders (WAD). The aim of the study was to investigate postural sway in individuals with chronic WAD grades 2 and 3: (a) compared with healthy matched controls at baseline; (b) after three months of neck-specific exercise and (c) to investigate the correlation between postural sway with self-reported dizziness during motion and balance problems/unsteadiness. This is a longitudinal prospective experimental case-control intervention study. Individuals with WAD (n = 30) and age- and gender-matched healthy volunteers (n = 30) participated. Postural sway was assessed using an iPhone application. Measurements were carried out at baseline, and for those with WAD a second measurement was performed at the three-month follow-up when neck-specific exercise intervention ended. The WAD group performed significantly worse than the healthy group in both pathway and ellipse area double stance eyes closed at baseline (main outcome), but not at the three-month follow-up. The WAD group significantly improved after rehabilitation in both pathway double stance eyes closed and pathway single stance eyes open. The correlation between postural sway and self-rated dizziness during motion and balance problems was low to moderate. One may conclude that postural sway was improved after a neck-specific exercise programme. The study results strengthen earlier findings that individuals with WAD have worse balance outcome when they have to rely on neck proprioception (eyes closed). The study results may be important for the development of improved rehabilitation methods for WAD.

Effect of a slump posture on pain, proprioception, and electrical activity of the muscles in office workers with chronic non-specific neck pain. A retrospective study

BACKGROUND

The impact of computer typing in a slump posture on pain, proprioception and muscle recruitment has not been extensively investigated. Therefore, the purpose of this study was to evaluate the extent of pain, proprioception and muscle activity resulting from computer typing in a slump posture in women who already suffer from chronic neck pain.

METHODS

This cross-sectional study was conducted between May 20 to July 10, 2021. A total of 15 female 42-(±4.96)-year-old office workers with chronic non-specific neck pain participated in this study. Before and after 60 min of computer typing in a slump posture, proprioception and pain were measured using an inclinometer and visual analog scale (VAS), respectively. The activity of the cervical erector spine (CES) and upper trapezius (UT) muscle was also measured before and after the slump-posture computer typing, in upright, forward, and slump postures. RESU: lts: Paired-samples t-tests showed that pain was increased and proprioception in all directions (flexion, extension, right and left lateral flexion, and right, and left rotation) was less accurate (P < 0.05) after 60 min computer typing. The CES and UT muscle activity were elevated more in the forward head and slump posture than in the upright posture (P < 0.05).

CONCLUSION

Sixty minutes computer typing in a slump posture increased neck pain, resulted in a decreased proprioception in the neck and was accompanied by an increased activity of the neck musculature.

Relationship between Fear-Avoidance Beliefs and Reaction Time Changes Prior to and following Exercise-Induced Muscle Fatigue in Chronic Low Back Pain

Background

Reaction time is a reliable indicator of the velocity and efficiency of neuromuscular control and may be associated with fear-avoidance beliefs. However, the effect of exercise-induced muscle fatigue on reaction time in chronic low back pain (cLBP) and its relationship with fear-avoidance beliefs remains poorly understood.

Objectives

This study aimed to reveal the relationship between fear-avoidance beliefs and reaction time changes before and after exercise-induced muscle fatigue in cLBP.

Methods

Twenty-five patients with cLBP were tested by the Biering-Sorensen test (BST) to induce exhaustive muscle fatigue. Total reaction time (TRT), premotor time (PMT), and electromechanical delay (EMD) of dominated deltoid muscle were recorded by surface electromyography during the arm-raising task with visual cues before and after muscle fatigue. The mean difference (MD) of TRT (MDTRT), PMT (MDPMT), and EMD (MDEMD) was calculated from the changes before and after muscle fatigue. Fear-avoidance beliefs questionnaire (FABQ) was applied to evaluate fear-avoidance beliefs before muscle fatigue. In addition, the duration time of BST was recorded for each subject.

Results

TRT and PMT of dominated deltoid muscle were prolonged after exercise-induced muscle fatigue (Z = 3.511, p < 0.001; t = 3.431, p = 0.001), while there was no statistical difference in EMD (Z = 1.029, p = 0.304). Correlation analysis showed that both the MDTRT and MDPMT were positively correlated with FABQ (r = 0.418, p = 0.042; r = 0.422, p = 0.040).

Conclusions

These findings suggested that we should pay attention to both muscle fatigue-induced reaction time delay in cLBP management and the possible psychological mechanism involved in it. Furthermore, this study implied that FABQ-based psychotherapy might serve as a potential approach for cLBP treatment by improving reaction time delay. This trial is registered with ChiCTR2300074348.

Can baseline features predict a reduction in pain and disability following neck-specific exercise in people with chronic non-specific neck pain?: A systematic review and meta-analysis protocol

INTRODUCTION

Neck-specific exercises (NSEs) are commonly used for the treatment of chronic non-specific neck pain (CNSNP). However, it remains unclear whether baseline features can predict the response to neck-specific exercise (NSE) in people with CNSNP. This systematic review aims to assess whether baseline features such as age, gender, muscle activity, fatigability, endurance and fear of movement can predict pain and disability reduction following a NSE intervention.

METHODS AND ANALYSIS

This systematic review and meta-analysis will be reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Protocols guidelines checklist. The Web of Science, PubMed, Scopus, MEDLINE, Embase and CINAHL databases; key journals; and grey literature will be searched up until June 2023, including medical subject heading terms and keywords combinations. Included studies will investigate an association between the baseline features and pain and disability outcomes following NSE in people with CNSNP. Two independent reviewers will oversee the searching, screening, data extraction and assessment of risk of bias. The risk of bias will be assessed using the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I) and Risk-Of-Bias tool for randomised trials 2 (ROB 2). The quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation approach (GRADE). Using standardised forms, details regarding study characteristics, baseline features (predictive factors), intervention, primary outcome and effect size (OR and 95% CI of each predictive factor and p value) will be extracted from included studies. Meta-analyses will be considered, if the studies are sufficiently homogeneous and if three or more studies investigate the same or comparable factors that predict the same response (pain intensity or disability). In the event that less than three studies investigated the same factors, a narrative synthesis will be conducted.

ETHICS AND DISSEMINATION

Ethical approval will not be required as this review will be based on published studies. The results of this study will be submitted to a peer-reviewed journal and presented at conferences.

PROSPERO REGISTRATION NUMBER

CRD42023408332.

The effect of chronic low back pain on postural control during quiet standing: A meta-analysis

Low back pain (LBP) has been associated with altered body sway during quiet standing, but the pattern of results is inconsistent. The purpose of this meta-analysis is to examine the effects of vision (eyes open, eyes closed) and changing the support surface (foam surface, firm surface) on postural sway during quiet standing in individuals with chronic LBP (cLBP). Five electronic databases were searched on March 27th, 2022. Of 2,856, 16 studies (n = 663) were included. Across all conditions, we found a positive and medium effect size (g = 0.77 [0.50, 1.04]) that represented greater body sway in individuals with cLBP. Subgroup analyses revealed medium effects during eyes open conditions (firm surface: g = 0.60 [0.33, 0.87]; foam surface: g = 0.68 [0.38, 0.97]), and large effects during eyes closed conditions (firm surface: g = 0.97 [0.60, 1.35]; foam surface: g = 0.89 [0.28, 1.51]). We quantified effects of self-reported pain and found a moderate effect during eyes closed plus firm surface conditions (Q = 3.28; p = 0.070). We conclude that cLBP is associated with increased postural sway, with largest effect sizes evident when vision is removed and when self-reported pain intensity is higher.

Cervical Paraspinal Muscle Fatty Infiltration is Directly Related to Extension Reserve in Patients With Cervical Spine Pathology

STUDY DESIGN/SETTING

Retrospective review of a prospectively collected database.

OBJECTIVE

The objective of this study was to determine the relationship between paracervical muscle area, density, and fat infiltration and cervical alignment among patients presenting with cervical spine pathology.

BACKGROUND CONTEXT

The impact of cervical spine alignment on clinical outcomes has been extensively studied, but little is known about the association between spinal alignment and cervical paraspinal musculature.

METHODS

We examined computed tomography scans and radiographs for patients presenting with cervical spine pathology. The posterior paracervical muscle area, density, and fat infiltration was calculated on axial slices at C2, C4, C6, and T1. We measured radiographic parameters including cervical sagittal vertical axis, cervical lordosis, T1 slope (T1S), range of motion of the cervical spine. We performed Pearson correlation tests to determine if there were significant relationships between muscle measurements and alignment parameters.

RESULTS

The study included 51 patients. The paracervical muscle area was higher for males at C2 ( P =0.005), C4 ( P =0.001), and T1 ( P =0.002). There was a positive correlation between age and fat infiltration at C2, C4, C6, and T1 (all P <0.05). The cervical sagittal vertical axis positively correlated with muscle cross-sectional area at C2 ( P =0.013) and C4 ( P =0.013). Overall cervical range of motion directly correlated with muscle density at C2 ( r =0.48, P =0.003), C4 ( r =0.41, P =0.01), and C6 ( r =0.53. P <0.001) and indirectly correlated with fat infiltration at C2 ( r =-0.40, P =0.02), C4 ( r =-0.32, P =0.04), and C6 ( r =-0.35, P =0.02). Muscle density correlated directly with reserve of extension at C2 ( r =0.57, P =0.009), C4 ( r =0.48, P =0.037), and C6 ( r =0.47, P =0.033). Reserve of extension indirectly correlated with fat infiltration at C2 ( r =0.65, P =0.006), C4 ( r =0.47, P =0.037), and C6 ( r =0.48, P =0.029).

CONCLUSIONS

We have identified specific changes in paracervical muscle that are associated with a patient's ability to extend their cervical spine.

The Mediating Effect of Age, Gender, and Post-Stroke Duration on the Association between Trunk and Upper Limb Recovery in Subacute Stroke Population: A Cross-Sectional Study with Mediation Analysis

BACKGROUND

The trunk acts as proximal support with which limbs execute smooth and purposeful movement. Furthermore, as upper extremity functions are an integral component of daily living activities, exploring the association between trunk and upper extremity recovery will guide therapists in developing appropriate rehabilitation goals and interventions. The objectives of this study were to (1) assess the association between trunk and upper extremity recovery in the subacute stroke population and (2) assess the effect of trunk control on upper extremity impairment and function with age, gender, and duration of stroke as mediators using mediation analysis in subacute stroke individuals.

METHODS

This cross-sectional study included 54 subacute stroke participants with a mean age of 58.37 ± 6.11 years. The trunk impairment scale (TIS) assessed the trunk's stability, mobility, and coordination. The level of upper extremity impairment was evaluated using the Fugl-Meyer Assessment scale (FMA). The quality and quantity of upper limb motor functions were measured using the Wolf motor function test (WMFT).

RESULTS

The TIS exhibited moderate positive correlations with the FMA-UE, WMFT-time scale (TS), and WMFT-functional ability scale (FAS) at p < 0.001. The mediation analysis reported a profound mediation effect of post-stroke duration on the association of trunk and upper limb recovery.

CONCLUSIONS

The study results substantiated that trunk control significantly correlates with upper limb impairment and the quality and quantity of its use in the subacute stroke population. Post-stroke duration proved to mediate the association between trunk and upper limb recovery. Therefore, the assessment and intervention of trunk and upper extremity motor control considering the post-stroke duration is vital and should be incorporated in stroke rehabilitation aiming at functional independence.

The Effect of Capacitive-Resistive Electrical Therapy on Neck Pain and Dysfunction in Horses

Neck pain and stiffness are increasingly recognized in horses and often treated using multimodal pharmaceutical and rehabilitation approaches. In humans, deep tissue heating is reported to reduce neck pain and increase flexibility. The objective of this project was to determine the effects of capacitive-resistive electrical therapy on neck pain and stiffness in horses. A blinded, randomized, controlled clinical trial with 10 horses assigned to active and 10 horses assigned to sham treatment groups. Neck pain, stiffness, and muscle hypertonicity were assessed by manual palpation. Forelimb postural stability was evaluated using a portable media device with built-in inertial sensing components. All outcome parameters were recorded once weekly for four weeks. Using manufacturer recommendations, the treatment group received active capacitive-resistive electrical therapy to the lower cervical region (C4-C7), twice weekly for a total of six treatments, while the control group received a sham (inactive) treatment. Data was analyzed using a mixed model that was fit separately for each response variable. There were no significant differences noted over time or between groups for any outcome parameter evaluated. While neck pain and stiffness decreased by week three in both groups, the improvement was not significant. Limitations include the lack of a definitive pathoanatomic diagnosis of cervical pathology and in vivo temperature measurements. Capacitive-resistive electrical therapy was ineffective in reducing neck pain and dysfunction using the recommended treatment protocols. No short-term adverse effects were noted. Specific clinical applications and effective treatment parameters need further evaluation.

Image Effect Observation of Acanthopanax senticosus on Antifatigue Activity after Exercise

In order to explore the effect of Acanthopanax senticosus on antifatigue activity after exercise, this paper proposes an image effect observation based on the effect of Acanthopanax senticosus on antifatigue activity after exercise. This method recommends key technical problems and solutions based on the information represented by image effect observation and explores the influence of Acanthopanax senticosus on antifatigue after exercise. Through the retrospective analysis of certain personnel, it is shown that the image effect observation based on the influence of Acanthopanax senticosus on the antifatigue activity after exercise is about 25% more accurate than the traditional method. Most of the active ingredients of Acanthopanax senticosus have phenolic hydroxyl groups, which can resist oxidation, fatigue, focus attention, and reduce work mistakes. This experiment shows that after sleep deprivation, the antioxidant capacity of the body decreases with time. Acanthopanax senticosus extract can significantly improve the above symptoms and fight fatigue.

Effect of Combined Manual Therapy and Therapeutic Exercise Protocols on the Postural Stability of Patients with Non-Specific Chronic Neck Pain. A Secondary Analysis of Randomized Controlled Trial

Postural stability is a little-studied factor in non-specific chronic neck pain; the causes that can alter it are unknown. The relationship with chronic pain could be a determining factor for its deficit. The aim of this study was to investigate the relationship between sustained pain and a postural stability deficit. A randomized and blinded clinical trial (double-blind; placebo control; 12 weeks follow-up) was conducted with a total of 69 subjects divided into three groups, two experimental (manual therapy and specific exercise) and a control treatment, and carried out over a treatment period of three weeks with a follow-up after 12 weeks. Their postural stability was assessed through the overall balance index (OBI). The postural stability of subjects with non-specific chronic neck pain improved in the experimental treatments. There were no statistically significant differences between the experimental groups. This trial found that manual therapy and therapeutic exercise significantly improved OBI compared to the control group. Trial registration: Brazilian Clinical Trial Registry, RBR-2vj7sw.

The study of respiratory muscles activation during respiratory muscle strength effort in adult females with chronic neck pain

[Purpose] This study aimed to compare maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP) values and muscle activity during MIP and MEP between chronic neck pain and healthy participants. [Participants and Methods] Twenty chronic neck pain and 20 non-symptomatic females participated in this study. Maximal airway pressure (MIP and MEP) and surface electromyography (sEMG) for both sides of the upper trapezius, anterior scalene, pectoralis major and 6th intercostal muscles were recorded simultaneously. [Results] Significant differences of MIP and MEP values were found between the groups. The muscle activities of both sides of upper trapezius and 6th intercostal muscles during MEP were significantly higher in the chronic neck pain group than the healthy group except both sides of anterior scalene and pectoralis major muscles. During MIP, the activities of upper trapezius, 6th intercostal muscles and anterior scalene were significantly different between the two studied groups. Higher activity of left pectoralis major was found in the chronic neck pain group. [Conclusion] Decreasing values of MEP and MIP as well as muscles activities elevation in chronic neck pain participants were clearly demonstrated. Besides the musculoskeletal treatment, we suggest breathing exercise training to be considered in treatment programs.

Comparison and Association of Neck Extensor Muscles’ Endurance and Postural Function in Subjects with and without Chronic Neck Pain – A Cross-Sectional Study

Purpose Neck extensor endurance (NEE) and position sense are vital for maintaining cervical spine function and defects in these processes may be associated with impaired postural control in chronic neck pain (CNP) subjects. The study’s objectives are 1) to compare the cervical extensor endurance capability and postural control of CNP subjects with those of asymptomatic controls; 2) to investigate the association between NEE and postural control.

Materials and Methods Sixty-four participants (38 asymptomatic, 38 with CNP) participated in this cross-sectional study. NEE was assessed using a clinical extensor endurance test. Under open and closed eyes conditions, postural control measures were tested with the Good Balance system. The postural control parameters were AP-velocity (mm/s), ML-velocity (mm/s) and Velocity moment (mm2). NEE capacity and postural control parameters were compared and correlated between asymptomatic and CNP subjects.

Results and Discussion CNP subjects showed lower NEE capacity (p<0.001) and significantly larger AP-velocity (p<0.001), ML-velocity (p<0.001) and Velocity moment (p<0.001) than asymptomatic participants. NEE negatively correlated with AP-velocity (r=−0.51, p=0.001), ML-velocity (r=0.46, p=0.003) and velocity moment (r=0.38, p=0.020) in asymptomatic subjects in eyes open condition and no correlations in subjects with CNP. CNP subjects showed increased postural sway velocities and lowered extensor endurance capacity compared to asymptomatic participants. No correlations existed between NEE and postural control parameters in CNP subjects.

Immediate and Short-Term Effects of Upper Cervical High-Velocity, Low-Amplitude Manipulation on Standing Postural Control and Cervical Mobility in Chronic Nonspecific Neck Pain: A Randomized Controlled Trial

This study aimed to determine the immediate and short-term effects of a single upper cervical high-velocity, low-amplitude (HVLA) manipulation on standing postural control and cervical mobility in chronic nonspecific neck pain (CNSNP). A double-blinded, randomized placebo-controlled trial was performed. Forty-four patients with CNSNP were allocated to the experimental group (n = 22) or control group (n = 22). All participants were assessed before and immediately after the intervention, with a follow-up on the 7th and 15th days. In each evaluation, we assessed global and specific stabilometric parameters to analyze standing postural balance and performed the cervical flexion-rotation test (CFRT) to analyze upper cervical mobility. We obtained statistically significant differences, with a large effect size, in the limited cervical rotation and global stabilometric parameters. Upper cervical HVLA manipulation produced an improvement in the global stabilometric parameters, significantly decreasing the mean values of velocity, surface, path length, and pressure in all assessments (p < 0.001; ƞ 2 p = 0.323–0.856), as well as significantly decreasing the surface length ratio (L/S) on the 7th (−0.219 1/mm; p = 0.008; 95% confidence interval (CI): 0.042–0.395) and 15th days (−0.447 1/mm; p < 0.001; 95% CI: 0.265–0.629). Limited cervical rotation values increased significantly immediately after manipulation (7.409°; p < 0.001; 95% CI: 6.131–8.687) and were maintained during follow-up (p < 0.001). These results show that a single upper cervical HVLA manipulation produces an improvement in standing postural control and increases the rotational range of motion (ROM) in the upper cervical spine in patients with CNSNP.

Upright Balance Control in Individuals with Cervical Myelopathy Following Cervical Decompression Surgery: A Prospective Cohort Study

Patients with cervical myelopathy may manifest impairments in functional activities and balance control caused by compression of the spinal cord. The objective of the current study was to determine long-term changes in the upright balance control of patients with cervical myelopathy who had undergone cervical decompression surgery. This is a prospective cohort study from the preoperative phase to 3 months, 6 months, and 1 year postsurgery. Fifty-three patients with cervical myelopathy were recruited for the cervical myelopathy group and 22 age-matched healthy controls were recruited for the control group. Functional assessments including Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire-Lower Extremity Function (JOACMEQ-LEF) and 10-second step test; as well as balance assessments including postural sway (center-of-pressure: COP) were performed for both groups. The JOACMEQ-LEF (p = 0.036) scores of the myelopathy group improved postoperatively, and a significant decrease in COP variables of postural sway was observed. The upright posture was less stable in the myelopathy group than in the control group (p < 0.05) both before and after surgery. The effect size and standard response mean of the COP variables ranged from −0.49 to 0.03 at 3 months, 6 months, and 1 year postsurgery. The upright balance control had improved significantly 6 months after decompression surgery. However, the balance control of the patients who had undergone decompression surgery remained less stable than that of the age-matched healthy controls. Balance training should be initiated before 6 months postsurgery to accelerate balance control recovery in patients with cervical myelopathy.

Perturbation-Based Balance Training in Postoperative Individuals With Degenerative Cervical Myelopathy

Degenerative cervical myelopathy (DCM) is a common aging condition caused by spinal cord compression. Individuals with DCM often presented with residual balance and functional impairments postoperatively. Perturbation-based balance training (PBT) has been shown to have positive effects on populations with neurological disorders but has yet to be investigated in DCM. The objective of this study was therefore to evaluate the effects of PBT on balance and functional performance in postoperative individuals with DCM. Fifteen postoperative individuals with DCM (DCM group) and 14 healthy adults (healthy control group) were recruited. The DCM group received a 4-weeks PBT using a perturbation treadmill. The outcome measures included mean velocity of center of pressure (COP) during quiet standing; center of mass (COM) variance and reaction time to balance perturbation during standing with forward and backward perturbation; gait speed during level ground walking; Timed Up and Go Test (TUG) and disability questionnaire scores including Visual Analog Scale, Neck Disability Index, and Lower Extremity Function of Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire. The assessments were conducted pre- and post-training postoperatively for the DCM group but only once for the healthy control group. Significant improvements were observed in the mean velocity of COP, COM variance, reaction time, gait speed, and TUG in the DCM group. Disability questionnaire scores were not significantly different after training in DCM group. For between-group comparisons, significant differences that were observed pre-training were not observed post-training. The 4-weeks PBT is a potential rehabilitation strategy for addressing balance and functional impairment in postoperative individuals with DCM. In addition, the post-training performance in the DCM group exhibited trends comparable to those of age-matched healthy controls. Furthermore, the training regimens offer a practical reference for future studies on populations with balance disorders. Future studies complemented with neurophysiological assessments could reveal more information of the underlying mechanisms of PBT.