Neck muscle strength and mobility of the cervical spine as predictors of neck pain: a prospective 6-year study

Physical fitness characteristics and neck and shoulder pain incidence in school-aged children-A 2-year follow-up

Background and Aims

Neck and shoulder pain (NSP) is common in school age, but preventative factors have not been identified. The purpose was to study whether a fitness test could be used to predict the incidence of NSP and determine whether good physical fitness characters would be associated with lower NSP incidence in school-aged children at 2-year follow-up.

Methods

After the invitation to nine schools, 970 children (10-15 years old) agreed to participate. Flexibility, fundamental movement skills, musculoskeletal fitness, and cardiorespiratory fitness measurements included in Finnish Schools on the Move! monitoring system for physical functional capacity were measured at baseline in 2013. The NSP incidence was assessed by an online survey during school hours after 1 and 2 years. Logistic regression was used to analyze associations between physical fitness characteristics and NSP incidence.

Results

The mean prevalence of NSP was 26% at baseline. The NSP incidence was 15% in the first and 18% in the second follow-up year. Good physical fitness was not associated with lower NSP incidence in the 2-year follow-up. Successful lower back extension (odds ratio [OR] = 2.83) and good scores in curl-up (OR = 1.80) adjusted with age, gender, and body mass index, were associated with higher NSP incidence between T0 and T2. Throwing-catching combination (OR = 0.55) was associated with a lower NSP incidence in unadjusted analysis, but the association did not remain after adjustments.

Conclusion

Good physical fitness characteristics were not consistently associated with a lower NSP incidence in school-aged children in a 2-year follow-up. The role of general field-based physical fitness test as a screening tool for NSP incidence remains unconfirmed. More longitudinal studies are needed to detect the factors underlying NSP incidence in school-aged children.

Neck Strength in Coronal and Sagittal Head Movement in Military Pilots and Aircrew With Chronic Neck Pain: A Systematic Review With Meta-Analysis

OBJECTIVE

This systematic review aimed to assess whether there is a difference in neck strength between military pilots and aircrew with and without chronic neck pain.

METHODS

The PubMed, Embase, and Scopus databases were searched. Two independent reviewers selected relevant full articles comparing neck strength between military pilots and aircrew with and without chronic neck pain. Two independent reviewers extracted the data from the full articles selected. A meta-analysis was used to assess standardized mean differences in neck strength based on a random-effects model.

RESULTS

The search returned 3554 results; 5 articles were included in the study. Military pilots and aircrew with chronic neck pain showed no difference in neck strength from military pilots and aircrew without chronic neck pain for flexion and extension, but did show a neck strength reduction for right and left lateral flexion -0.29 (95% confidence interval, -0.52 to -0.06; I² = 3%) and -0.23 (95% confidence interval, -0.45 to 0.00; I² = 0%), respectively.

CONCLUSION

Based on this meta-analysis with a 3a level of evidence, military pilots and aircrew with chronic neck pain have reduced neck strength for coronal head movement, but not sagittal movement compared with military pilots and aircrew without chronic neck pain.

Associations of neck muscle strength and cervical spine mobility with future neck pain and disability: a prospective 16-year study

Background

Neck pain has been associated with weaker neck muscle strength and decreased cervical spine range of motion. However, whether neck muscle strength or cervical spine mobility predict later neck disability has not been demonstrated. In this 16-year prospective study, we investigated whether neck muscle strength and cervical spine mobility are associated with future neck pain and related disability in women pain-free at baseline.

Methods

Maximal isometric neck muscle strength and passive range of motion (PROM) of the cervical spine of 220 women (mean age 40, standard deviation (SD) 12 years) were measured at baseline between 2000 and 2002. We conducted a postal survey 16 years later to determine whether any subjects had experienced neck pain and related disability. Linear regression analysis adjusted for age and body mass index was used to determine to what extent baseline neck strength and PROM values were associated with future neck pain and related disability assessed using the Neck Disability Index (NDI).

Results

The regression analysis Beta coefficient remained below 0.1 for all the neck strength and PROM values, indicating no association between neck pain and related disability. Of the 149 (68%) responders, mean NDI was lowest (3.3, SD 3.8) in participants who had experienced no neck pain (n = 50), second lowest (7.7, SD 7.1) in those who had experienced occasional neck pain (n = 94), and highest (19.6, SD 22.0) in those who had experienced chronic neck pain (n = 5).

Conclusions

This 16-year prospective study found no evidence for an association between either neck muscle strength or mobility and the occurrence in later life of neck pain and disability. Therefore, screening healthy subjects for weaker neck muscle strength or poorer cervical spine mobility cannot be recommended for preventive purposes.

Sex and posture dependence of neck muscle size-strength relationships

Neck muscle size and strength have been linked to lower injury risk and reduced pain. However, prior findings have been inconclusive and have failed to clarify whether there are sex differences in neck muscle size-strength relationships. Such differences may point to an underlying cause for the reported sex difference in neck pain prevalence. Thirty participants (13 males, 17 females) who underwent neck strength testing and MR imaging were analyzed. Strength was measured in three conditions that differed in posture and exertion direction. Muscle size was quantified by three metrics: anatomical cross-sectional area (ACSA), muscle volume (MV), and an estimate of physiological cross-sectional area-reconstruction-based cross-sectional area (RCSA). Inter-posture strength correlations, muscle size-strength correlations, and sex differences were analyzed with linear regression. Males were approximately 65% stronger and had significantly larger muscles. Strength varied significantly across postures, but only female strength values for different postures were significantly correlated. Observed in males only, the sternocleidomastoid (SCM) was a strong predictor of flexion strength in the neutral posture while the anterior scalene (AS) was more involved in the extended. No extensor's size was significantly linked to extension strength. A greater amount of force variation is unexplained by muscle size alone in females than in males. Males and females exhibited distinct size-strength relationships, highlighting the need for sex-specific models and analyses and the greater potential effect of non-morphometric factors on force generating capacity in females. No advantage of one muscle size metric over another in strength prediction was evidenced.

Reliability and Validity of Clinical Tests for Measuring Strength or Endurance of Cervical Muscles: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the reliability and validity of clinical tests for measuring cervical muscle strength or endurance in participants with and without neck pain.

DATA SOURCE

Systematic review and meta-analysis on reliability and validity. Literature search was conducted on January 28, 2020, using 5 databases: MEDLINE, Cumulative Index to Nursing and Allied Health, EMBASE, SPORTDiscus, and Scopus.

STUDY SELECTION

We included studies that investigated the reliability or validity of clinical tests for measuring cervical muscle strength or endurance in participants with nonspecific chronic neck pain, with or without irradiation, or healthy participants. We included only those that were viable for daily practice and of low cost.

DATA EXTRACTION

Data were extracted as follows: (1) author and year of publication, (2) demographic values and health condition, (3) reported clinical tests, (4) inclusion and exclusion criteria, (5) description of test, (6) interrater reliability, and (7) intrarater reliability. For validity studies we also extracted the (8) reference method and (9) validity estimates.

DATA SYNTHESIS

Methodological quality was assessed with the Quality Appraisal of Diagnostic Reliability and the Guidelines for Reporting Reliability and Agreement Studies. Data on reliability and validity were extracted from included articles and then analyzed.

RESULTS

Thirty-one studies were included. Cervical flexor and extensor endurance test, craniocervical flexion test (CCFT), AND cervical muscle strength using a handheld dynamometer (HHD) showed moderate to good intra- and interrater reliability (intraclass correlation coefficients ranging from 0.64-0.90). Concurrent validity was measured by only 2 studies, which do not provide adequate evidence for a recommendation.

CONCLUSIONS

The cervical flexor and extensor endurance tests, CCFT, and HHD for measuring cervical strength presented an acceptable interrater and intrarater reliability.

Longitudinal study exploring factors associated with neck/shoulder pain at 52 years of age

OBJECTIVES

To investigate the ability of work-related measurements, body composition, physical activity, and fitness levels to predict neck/shoulder pain (upper body pain, UBP) at the age of 52 years. Another aim was to investigate the cross-sectional relationships between UBP, work-related factors, and individual factors at the age of 52 years.

METHODS

We followed a randomly selected cohort of 429 adolescents that was recruited in 1974 (baseline), when they were 16 years old. The participants completed physical fitness tests, questions about sociodemographic and lifestyle factors at 16, 34, and 52 years of age, and questions about work-related factors and pain in the follow-ups. Logistic regression analyses were used to examine the associations between UBP and the other variables.

RESULTS

Univariate logistic regression analyses showed that high body mass index and the work-related factors, low control, and low social support at the age of 34 years were related to UBP at the age of 52 years. For social support, there was an interaction between men and women where the relationship between low social support and the experience of pain was more evident for women. Among women, body mass index and social support remained significantly related in the multivariate analyses. For men, social support remained significantly related. Cross-sectional relationships at the age of 52 differed from the longitudinal in the sense that measures of joint flexibility and work posture were also significantly associated with UBP.

CONCLUSION

The fact that the cross-sectional differed from the longitudinal relationships strengthens the importance of performing longitudinal studies when studying factors that might influence the initiation of pain. UBP preventative measures might need to include both lifestyle (such as dietary habits and physical activity to ensure that the individuals are not becoming overweight) and work-related factors such as social support.

Local Muscle Fatigue and 3D Kinematics of the Cervical Spine in Healthy Subjects

The authors aimed to further explore the effects of local muscle fatigue on cervical 3D kinematics and the interrelationship between these kinematic characteristics and local muscle endurance capacity in the unimpaired cervical spine. Twenty healthy subjects (38 ± 10 years; 5 women) performed 2 × 10 maximal cervical flexion-extension movements. Isometric muscle endurance tests (prone/supine lying) were applied between sets to induce local muscle fatigue quantified by Borg scale rates of perceived exertion (RPE) and slope in mean power frequency (MPF; surface electromyography; m. sternocleidomastoideus, m. splenius capitis). Cervical motion characteristics (maximal range of motion [ROM], coefficient of variation of the 10 repetitive movements, mean angular velocity, conjunct movements in transversal and frontal plane) were calculated from raw 3D ultrasonic movement data. Average isometric strength testing duration for flexion and extension correlated to the cervical ROM (r = .49/r = .48; p < .05). However, Student's t test demonstrated no significant alterations in any kinematic parameter following local muscle fatigue (p > .05). Although subjects' cervical muscle endurance capacity and motor output seems to be conjugated, no impact of local cervical muscle fatigue on motor function was shown. These findings underline the importance of complementary measures to address muscular performance and kinematic characteristics in outcome assessment and functional rehabilitation of the cervical spine.