The Relationship of Ultrasound Measurements of Muscle Deformation With Torque and Electromyography During Isometric Contractions of the Cervical Extensor Muscles.

OBJECTIVES: Speckle tracking analysis (STA) of ultrasound (US) images quantifies the longitudinal deformation of a region of muscle tissue to provide a mechanical measure of muscle activity. As the validity and reliability of this method has not yet been adequately assessed, the aim of this study was to determine the validity and reliability of STA in the dorsal neck muscles during isometric neck extension contractions. METHODS: Twenty volunteers performed 3 repetitions of isometric neck extension in a dynamometer at 10%, 20%, 40%, 60%, and 80% of maximal voluntary torque while US and surface electromyography (EMG) data were recorded. Speckle tracking analysis was then used to calculate measurements of muscle deformation. The relationship among torque, muscle deformation (separate for each muscle and summed), and EMG was evaluated using linear regressions and Spearman's correlation coefficients. The reliability of EMG and muscle deformation was determined using intraclass correlation coefficients (ICCs). RESULTS: Muscle deformation in 4 of the 5 muscles when examined separately and collectively was significantly related to torque (P < .05); however, the relationship was weak (r2 = 0.03-0.18). In contrast, a strong linear relationship was observed between torque and EMG (P < .001, r2 = 0.83). Poor to moderate reliability of muscle deformation measures (ICC: 0.02-0.69) was found compared with EMG, which was highly reliable (ICC: 0.67-0.90). CONCLUSION: These results suggest that the validity of US STA measurements for isometric contractions of the dorsal neck muscles is questionable. Further investigation into this method is required before it can be used as a tool to measure muscle activity.

Ultrasound Investigation of Dorsal Neck Muscle Deformation During a Neck Rotation Exercise.

OBJECTIVES: Neck-specific exercise can reduce neck pain and increase function, but information on how different neck muscle layers are activated during neck exercises is scarce. The aim of this study was to investigate deformation and deformation rate in 5 dorsal neck muscles and the correlation among these muscles during a loaded dynamic exercise used in clinical practice. METHODS: Deformation and deformation rate were investigated in 5 dorsal right-sided neck muscles in 20 individuals without neck pain using ultrasonography and speckle-tracking analyses. Repeated-measures analysis of variance was used to measure differences between the muscles, and correlations between neck muscles were analyzed with Kendall's tau. RESULTS: Deformation in left (contralateral) rotation showed significant differences among the muscles (P = .01), with higher deformation of the semispinalis capitis muscle compared with the trapezius muscle (P = .02). There were no significant differences among the 5 neck muscles in right (unilateral) rotation (P = .46). There were significant differences in deformation rate among muscles in both right and left rotation (P < .01). The trapezius muscles have the lowest deformation rate in right rotation (P < .01). In left rotation, the trapezius and multifidus muscles showed lower deformation rates compared with most of the other muscles (P < .03). Almost all muscles were correlated in both deformation and deformation rate. CONCLUSION: The quadruped standing loaded dynamic neck exercise seemed to activate all the investigated neck muscles, with a tendency for more activation of the semispinalis capitis.

Multifidus muscle size changes at different directions of head and neck movements in females with unilateral chronic non-specific neck pain and healthy subjects using ultrasonography.

OBJECTIVE: The aim of the study was to compare the dimensions of cervical multifidus muscle (CMM) in different conditions. METHODS: Twenty five women with neck pain and 25 healthy subjects participated in this study. The dimensions of the CMM were measured at rest, 50% and 100% maximum isometric voluntary contraction (MIVC) at six directions of neck movements, using ultrasonography. RESULTS: The size of multifidus was smaller in patients than healthy individuals at rest state (P < 0.05). A significant smaller CMM dimension was found in the affected side compared with unaffected side in patients group (P < 0.05). The result of ANOVA for MLD showed a significant difference for contraction levels (P < 0.001) and neck movements (P < 0.001) in both groups. The MLD of the CMM was significantly different between CMM at rest and 50%, and 100% MIVC (P < 0.001). No significant differences were found between the groups at 50% and 100% MIVC (P > 0.05 in both instances). The most prominent CMM size change was observed during neck extension, flexion, ipsilateral lateral-flexion, and ipsilateral rotation, respectively (P < 0.05). CONCLUSIONS: Results of the present study indicate that the size of CMM was decreased in patients with neck pain in rest state. The size of CMM changes in all directions of neck movements, although the most prominent was during neck extension. This points out CMM stabilization role's in different directions of neck movements.

Neck-Related Physical Function, Self-Efficacy, and Coping Strategies in Patients With Cervical Radiculopathy: A Randomized Clinical Trial of Postoperative Physiotherapy.

OBJECTIVE: The purpose of this study was to compare postoperative rehabilitation with structured physiotherapy to the standard approach in patients with cervical radiculopathy (CR) in a prospective randomized study at 6 months follow-up based on measures of neck-related physical function, self-efficacy, and coping strategies. METHODS: Patients with persistent CR and scheduled for surgery (N = 202) were randomly assigned to structured postoperative physiotherapy or a standard postoperative approach. Structured postoperative physiotherapy combined neck-specific exercises with a behavioral approach. Baseline, 3-month, and 6-month evaluations included questionnaires and clinical examinations. Neck muscle endurance, active cervical range of motion, self-efficacy, pain catastrophizing (CSQ-CAT), perceived control over pain, and ability to decrease pain were analyzed for between-group differences using complete case and per-protocol approaches. RESULTS: No between-group difference was reported at the 6-month follow-up (P = .05-.99), but all outcomes had improved from baseline (P < .001). Patients undergoing structured postoperative physiotherapy with ≥50% attendance at treatment sessions had larger improvements in CSQ-CAT (P = .04) during the rehabilitation period from 3 to 6 months after surgery compared with the patients who received standard postoperative approach. CONCLUSIONS: No between-group difference was found at 6 months after surgery based on measures of neck-related physical function, self-efficacy, and coping strategies. However, the results confirm that neck-specific exercises are tolerated by patients with CR after surgery and may suggest a benefit from combining surgery with structured postoperative physiotherapy for patients with CR.

The effect of 3 different exercise approaches on neck muscle endurance, kinesiophobia, exercise compliance, and patient satisfaction in chronic whiplash.

OBJECTIVE: The purpose of this study was to compare the effects of 3 different exercise approaches on neck muscle endurance (NME), kinesiophobia, exercise compliance, and patient satisfaction in patients with chronic whiplash. METHODS: This prospective randomized clinical trial included 216 individuals with chronic whiplash. Participants were randomized to 1 of 3 exercise interventions: neck-specific exercise (NSE), NSE combined with a behavioral approach (NSEB), or prescribed physical activity (PPA). Measures of ventral and dorsal NME (endurance time in seconds), perceived pain after NME testing, kinesiophobia, exercise compliance, and patient satisfaction were recorded at baseline and at the 3- and 6-month follow-ups. RESULTS: Compared with individuals in the prescribed physical activity group, participants in the NSE and NSEB groups exhibited greater gains in dorsal NME (P = .003), greater reductions in pain after NME testing (P = .03), and more satisfaction with treatment (P < .001). Kinesiophobia and exercise compliance did not significantly differ between groups (P > .07). CONCLUSION: Among patients with chronic whiplash, a neck-specific exercise intervention (with or without a behavioral approach) appears to improve NME. Participants were more satisfied with intervention including neck-specific exercises than with the prescription of general exercise.

Longitudinal changes in ventral and dorsal neck muscle layers during loading against gravity in healthy volunteers using speckle tracking.

OBJECTIVE: This study aimed to describe and compare the longitudinal mechanical activity, deformation, and deformation rate of the different layers of dorsal and ventral neck muscles in healthy volunteers during head lifts against gravity. METHODS: The cross-sectional study included 19 healthy volunteers (mean age, 28 years; SD, 7 years). Ultrasound with speckle-tracking analysis was used to investigate longitudinal mechanical activation, deformation, and deformation rate of dorsal and ventral neck muscles in real time during a head lift. Significance levels were set as P = .025 or P = .0125, depending on the number of comparisons. RESULTS: The dorsal neck muscles did not significantly differ in deformation (P > .04); however, the multifidus had a higher deformation rate than all other dorsal muscles (P < .003). The sternocleidomastoid had significantly higher deformation than the longus capitis (P = .005) and colli (P = .001) but a lower deformation rate than the longus colli (P = .02). CONCLUSION: The sternocleidomastoid deformed more than the deeper muscles, but it did significantly slower than the longus colli. Among the dorsal muscles, the deepest (the multifidus) had the highest deformation rate.

Function in patients with cervical radiculopathy or chronic whiplash-associated disorders compared with healthy volunteers.

OBJECTIVE: The purposes of this study were to examine whether any differences in function and health exist between patients with cervical radiculopathy (CR) due to disk disease scheduled for surgery and patients with chronic whiplash-associated disorders (WADs) and to compare measures of patients' physical function with those obtained from healthy volunteers. METHODS: This is a cross-sectional study of patients with CR (n = 198) and patients with chronic WAD (n = 215). Patient data were compared with raw data previously obtained from healthy people. Physical measures included cervical active range of motion, neck muscle endurance, and hand grip strength. Self-rated measures included pain intensity (visual analog scale), neck disability (Neck Disability Index), self-efficacy (Self-Efficacy Scale), and health-related quality of life (EuroQol 5-dimensional self-classifier). RESULTS: Patient groups exhibited significantly lower performance than the healthy group in all physical measures (P < .0005) except for neck muscle endurance in flexion for women (P > .09). There was a general trend toward worse results in the CR group than the WAD group, with significant differences in neck active range of motion, left hand strength for women, pain intensity, Neck Disability Index, EuroQol 5-dimensional self-classifier, and Self-Efficacy Scale (P < .0001). CONCLUSIONS: Patients had worse values than healthy individuals in almost all physical measures. There was a trend toward worse results for CR than WAD patients.

Evaluation of physical function in individuals 11 to 14 years after anterior cervical decompression and fusion surgery--a comparison between patients and healthy reference samples and between 2 surgical techniques.

OBJECTIVE: The purpose of this study was to evaluate neck-related physical function in individuals 11 to 14 years after anterior cervical decompression and fusion (ACDF) surgery for degenerative cervical disk disease and to compare the long-term outcome of 2 surgical techniques, including the Cloward procedure and cervical intervertebral fusion cage. METHODS: In this cross-sectional study, 51 individuals, 11 years or more after ACDF, underwent testing of cervical active range of motion, hand-grip strength, static and dynamic balance, neck muscle endurance, and completed pain ratings. The participants' values were compared with values of age- and sex-matched healthy individuals to evaluate impairments. Correlations between different test scores and pain were performed. Group differences were analyzed between the 2 surgical techniques. RESULTS: Sixty-five percent and 82% exhibited impairment in ventral and dorsal neck muscle endurance, respectively. Impairment rates of 18% to 39% for cervical active range of motion, 27% to 43% for hand-grip strength, 37% for standing balance, and 35% for dynamic balance were recorded. Twenty-nine percent of the participants had impairment (>30 mm visual analog scale) in pain. There were no significant differences in physical function between the 2 surgical treatment groups (Cloward procedure or cervical intervertebral fusion cage) (P = .10-.92). CONCLUSIONS: In those studied, a large percentage of patients who had anterior cervical decompression and fusion surgery have impairments in neck-related physical function when compared 11 to 14 years after surgery with age- and sex-matched healthy reference individuals. Neck-specific function, but not balance, was statistically correlated to pain. Neck muscle endurance was most affected, and balance impairments were also present in one-third of the individuals. There were no differences in long-term physical function between the 2 surgical techniques.

Cervical muscle activity during loaded arm lifts in patients 10 years postsurgery for cervical disc disease.

OBJECTIVE: The purpose of this study was to compare the mechanical activity of the neck muscles during loaded arm lifting tasks in individuals with long-standing disability after anterior cervical decompression and fusion (ACDF) with that of healthy controls. METHODS: Ten individuals (mean age, 60 years; SD, 7.1) who underwent ACDF (10-13 years previously) for cervical disc disease and 10 healthy age- and sex-matched controls participated in the study. Ultrasonography was used to investigate the degree of deformation and deformation rate of ventral and dorsal neck muscles at the C4 segmental level during a single (1× arm flexion to 120°) and repeated (10× arm flexion to 90°) loaded arm elevation condition. RESULTS: The ACDF group showed greater deformation and deformation rate of the longus capitis (P=.02) and deformation rate of the sternocleidomastoid (P=.04) during the 120° arm lift. For repeated 90° arm lift, there was a significant group effect with higher deformation rate values observed in the longus capitis (P=.005-.01) and multifidus (P=.03) muscles in the ACDF group. Muscle behavior did not change the repeated arm lifts (no group×time interactions) for either the ventral or the dorsal muscles. CONCLUSIONS: For study participants, greater muscle mechanical activity levels were observed in the ventral and multifidus muscles of patients with persistent symptoms after ACDF. These differences may indicate altered motor strategy in this patient group when performing the upper limb task and may need to be considered when prescribing exercise for postsurgical rehabilitation.

Neck muscle endurance in nonspecific patients with neck pain and in patients after anterior cervical decompression and fusion.

OBJECTIVE: The purpose of this study was to investigate differences in ventral and dorsal neck muscle endurance (NME) among men and women with nonspecific neck pain (NP) or cervical disk disease (who had anterior cervical decompression and fusion [ACDF]) and healthy controls (C). Another purpose was to investigate changes in NME after intervention. METHODS: Neck muscle endurance was measured in patients with NP (n = 78) and ACDF (n = 25) before and after the treatment period, and their results were compared to each other and to sex-specific reference values from controls (n = 116) at both the individual and group levels. RESULTS: Patients had significantly decreased (P < .01) NME compared with control subjects, except for ventral NME in female patients with NP before treatment and male patients with ACDF after treatment. Female patients with ACDF had lower ventral NME than female patients with NP (P < .01). Among the patients, 35% to 100% had NME disability, with most of them having a lower rate than the 95% confidence interval of controls. Female patients with NP and male patients with ACDF showed improvement (P < .05) after treatment. Flexion/extension ratio in patients with NP (P = .36), but not in patients with ACDF (P < .0001), returned to normal levels after treatment. There was a significant negative correlation (P < .02) between NME and Neck Disability Index in both patient groups, except for ventral NME in patients with NP before treatment. CONCLUSION: Many patients had impairment in NME before and after treatment. This suggests that additional exercise of specific training for NME should be incorporated into the rehabilitation program, which may improve treatment outcome.

Age- and sex-specific reference values of a test of neck muscle endurance.

OBJECTIVE: This study evaluates age- and sex-specific reference values for neck muscle endurance (NME). METHODS: In this cross-sectional study, 116 randomly selected, healthy volunteers (ages 25-64 years) stratified according to age and gender participated. Dorsal and ventral NME was measured in seconds until exhaustion in a laying-down position. A weight of 4 kg for men or 2 kg for women was used in the dorsal procedure. The ventral procedure was performed without external load. Background and physical activity data were obtained and used in the analysis of NME performance. RESULTS: Mean values for dorsal and ventral NME were about 7 and 2.5 minutes for men and 8.5 and 0.5 minutes for women, respectively. The cutoff values for subnormal dorsal and ventral NME were 157 and 56 seconds for men and 173 and 23 seconds for women, respectively. Women's NME was 122% of men's NME in the dorsal (P = .17) and 24% of men's NME in the ventral (P < .0001) procedure. There were no significant differences among age groups. In multiple regression analysis, physical activity explained 4% of variability in the performance of the dorsal NME; and sex explained 37% of the variability in the performance of ventral NME. CONCLUSION: The reference values and the cutoff points obtained could be used in clinical practice to identify patients with a subnormal NME. Sex is an important consideration when using both the test procedure and the reference values.