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Background. Teaching is one of the professions where incidence and prevalence of neck pain is high. Prolonged use of computers, which has further increased due to online teaching amid pandemic, is known to cause neck pain and alter posture, while people with forward head posture (FHP) are prone to develop neck pain and related disability. Research has shown that impairment of deep cervical flexor (DCF) muscles leads to insufficiency in coordination, activation, overload, and poor support on cervical structures that further lead to development of neck pain and altered neck posture. The objective of this study was to see the effect of DCF muscle training using pressure biofeedback on pain and FHP in school teachers with neck pain. Methods. This observational study was conducted at medical center in school premises. Fifty-five school teachers aged between 25 and 40 years with experience of more than 5 years were invited to participate in this study. Subjects were divided in two groups. Both the groups received conventional exercises while in experimental group DCF muscle training using pressure biofeedback was given additionally. Pain and FHP were assessed using NPRS and cranio-vertebral angle using digital photograph technique, respectively, at baseline and end of four weeks of treatment. Results. Although pain and FHP improved in both the groups, mean improvement in both the measures was more in the group that also received DCF training using pressure biofeedback. Conclusions. This study shows that although pain and FHP improved following conventional exercises in school teachers with neck pain, mean improvement was more significant among those who received additional DCF muscle training using pressure biofeedback.

Background: Prolonged use of electronic devices in virtual classrooms can influence posture, neck angle, and body discomfort. Recent evidence suggests that not only “incorrect” postures but also sustained static positions, regardless of being ergonomically correct, contribute to musculoskeletal strain. However, limited studies have directly compared posture and discomfort across different types of devices in a virtual classroom setting. Objective: To evaluate differences in posture, neck angle, and body discomfort among female university students during the use of three electronic devices (smartphone, tablet, notebook) in a virtual classroom for 20 min. Methods: Twenty-four healthy female participants (aged 18–23 years) completed three randomized sessions using a smartphone, tablet, or notebook in a virtual classroom task. Posture was assessed using the Rapid Upper Limb Assessment (RULA), neck angle was measured via motion analysis, and body discomfort was rated with a standardized visual analog scale. Statistical analyses were performed using repeated-measures ANOVA with Bonferroni correction, with effect sizes reported. Results: Significant differences were observed in posture (RULA scores: smartphone 5.12 ± 1.26; tablet 4.62 ± 1.35; notebook 4.21 ± 1.32, p < 0.05), neck angle (smartphone 32.48 ± 11.81 and tablet 36.93 ± 7.97, p > 0.05; notebook 39.30 ± 7.82, p > 0.05), and body discomfort of all regions (VAS: smartphone 1.08 ± 1.69; tablet 1.06 ± 1.75; notebook 1.01 ± 1.66, p < 0.05). Although all devices induced discomfort after 20 min of sustained posture, the smartphone condition showed the greatest neck flexion and discomfort. Conclusion: This study demonstrates that sustained posture during virtual classroom activities leads to increased neck angle deviation and body discomfort, with device type influencing the magnitude of these effects. These findings highlight the importance of postural variability and active breaks, rather than relying solely on maintaining a “correct” posture, to reduce musculoskeletal strain in technology-based learning environments.

To investigate the influence of the amount of cervical movement on the cervico-ocular reflex (COR) and vestibulo-ocular reflex (VOR) in healthy individuals. Eye stabilization reflexes, especially the COR, are changed in neck pain patients. In healthy humans, the strength of the VOR and the COR are inversely related. In a cross-over trial the amplitude of the COR and VOR (measured with a rotational chair with eye tracking device) and the active cervical range of motion (CROM) was measured in 20 healthy participants (mean age 24.7). The parameters were tested before and after two different interventions (hyperkinesia: 20 min of extensive active neck movement; and hypokinesia: 60 min of wearing a stiff neck collar). In an additional replication experiment the effect of prolonged (120 min) hypokinesia on the eye reflexes were tested in 11 individuals. The COR did not change after 60 min of hypokinesia, but did increase after prolonged hypokinesia (median change 0.220; IQR 0.168, p = 0.017). The VOR increased after 60 min of hypokinesia (median change 0.155, IQR 0.26, p = 0.003), but this increase was gone after 120 min of hypokinesia. Both reflexes were unaffected by cervical hyperkinesia. Diminished neck movements influences both the COR and VOR, although on a different time scale. However, increased neck movements do not affect the reflexes. These findings suggest that diminished neck movements could cause the increased COR in patients with neck complaints.

Although young adults regularly perform tablet writing, biomechanics during the tablet writing with different tilt angles has not been studied. The objective of this study was to compare posture, muscle activity, and discomfort at the neck and shoulder between tablet writing with 0° (horizontal) and 30° tablet tilt angles over 40 minutes in healthy young adults. Twenty participants wrote continuously for 40 minutes on a tablet with both tilt angles in a randomized order. Between conditions, there was a 5-minute activity break. Differences in neck and shoulder posture, muscle activity, and discomfort between both tablet tilt angles and changes in the outcomes every 10 minutes over 40 minutes were investigated. With the tilted tablet, there were lower neck flexion (Z = -4.637, P<0.001), lower shoulder extension (Z = -3.734, P<0.001), and lower neck Visual Analogue Scale (VAS) (left; Z = -4.699, P<0.001 and right; Z = -3.874, P<0.001) as compared to the no tilt condition. However, the right upper trapezius muscle activity was higher in the tilted condition as compared to the no tilt one. Over 40 minutes, the neck VAS (left; χ2(4) = 30.235, P<0.001 and right; χ2(4) = 32.560, P<0.001) and heart rate variability (χ2(4) = 12.906, P = 0.012) showed notable increases after 20 minutes compared to baseline. In conclusion, adjusting the tablet tilt to 30° and limiting time spent to 20 minutes are recommended for young adults during the tablet writing to prevent neck problems.

Clinical management of whiplash-associated disorders is challenging and often unsuccessful, with over a third of whiplash injuries progressing to chronic neck pain. Previous imaging studies have identified muscle fat infiltration, indicative of muscle weakness, in the deep cervical extensor muscles (multifidus and semispinalis cervicis). Yet, kinematic and muscle redundancy prevent the direct assessment of individual neck muscle strength, making it difficult to determine the role of these muscles in motor dysfunction. The purpose of this study was to determine the effects of deep cervical extensor muscle weakness on multi-directional neck strength and muscle activation patterns. Maximum isometric forces and associated muscle activation patterns were computed in 25 test directions using a 3-joint, 24-muscle musculoskeletal model of the head and neck. The computational approach accounts for differential torques about the upper and lower cervical spine. To facilitate clinical translation, the test directions were selected based on locations where resistance could realistically be applied to the head during clinical strength assessments. Simulation results reveal that the deep cervical extensor muscles are active and contribute to neck strength in directions with an extension component. Weakness of this muscle group leads to complex compensatory muscle activation patterns characterized primarily by increased activation of the superficial extensors and deep upper cervical flexors, and decreased activation of the deep upper cervical extensors. These results provide a biomechanistic explanation for movement dysfunction that can be used to develop targeted diagnostics and treatments for chronic neck pain in whiplash-associated disorders.

Women frequently express heightened neck discomfort even though they exhibit smaller neck flexion (NF) during smartphone use. Differences in natural posture while using smartphones may result in varying muscle activation patterns between genders. However, no study focused on this issue. This study investigated the influence of gender on neck muscle activity and NF when using smartphones, ranging from slight (20°) to nearly maximal forward head flexion, across different postures. We analyzed smartphone usage patterns in 16 men and 16 women and examined these behaviors across different scenarios: standing, supported sitting, and unsupported sitting, at 20°, 30°, 40°, and the maximum head angles. During data collection, muscle activity was measured, expressed as a percentage of the maximum voluntary contraction (%MVC), in the cervical erector spinae (CES) and upper trapezius (UTZ), along with NF. Results show significant influences of gender, head angle, and posture on all measures, with notable interactions among these variables. Women displayed higher muscle activities in CES and UTZ, yet exhibited lesser NF, while using smartphones in both standing (12.3%MVC, 10.7% MVC, and 69.0°, respectively) and unsupported sitting (10.8%MVC, 12.3%MVC, and 71.8°, respectively) compared to men (standing: 9.5%MVC, 8.8%MVC, and 76.1°; unsupported sitting: 9.7%MVC, 10.8%MVC, and 76.1°). This study provides a potential rationale for gender-related disparities in injury outcomes, emphasizing that women experience higher neck and shoulder discomfort level, despite their smaller NF during smartphone use, as found in previous research. Additionally, the cervical flexion-relaxation phenomenon may occur when the head angle exceeded 40°. The near-maximum head angle during smartphone use might induce the cervical flexion-relaxation phenomenon, potentially aggravating neck issues. We recommend limiting smartphone usage postures that exceed the near-maximum head angle, as they are commonly adopted by individuals in the daily smartphone activities.

Muscle conditioning is a protocol that systematically alters the level of resting discharge of muscle spindle afferents, resulting in a relatively high or low muscle spindle afferent discharge. Previous studies have shown that this protocol alters the acuity of limb proprioception in a systematic way. We hypothesized that this protocol will also alter neck proprioceptive acuity, depending on the involvement of vestibular activation. In this pilot study, we investigated whether muscle conditioning alters the accuracy of head-to-trunk joint position sense with and without head position change. Young, healthy blind-folded participants lay on a bench with movement of the head-neck or neck-trunk restricted to the sagittal plane. When supine, the head-neck was rotated about the cervico-thoracic junction. When side-lying, the head was fixed while the trunk was rotated. Participants first memorised a target angle and indicated when they perceived that their head-neck or neck-trunk had reached the target angle. Experiments were performed after conditioning dorsal neck muscles (DNMs) to leave muscle spindles mechanically sensitive or not. Constant (directional) error of the perceived location of the target angle was significantly larger when DNMs were conditioned to leave their muscle spindles mechanically insensitive in the side lying posture only (mean difference between mechanically insensitive and mechanically sensitive DNM spindles of supine 1.5°, p  = 0.333; side-lying 7.843°, p  < 0.001). For absolute (magnitude of error without reference to direction) error, a significant mean difference between mechanically sensitive and insensitive DNM spindles was only found in the side lying posture (mean difference 4.87°, p  = 0.002). The present results suggest that muscle conditioning applied to the DNMs affects head-to-trunk joint position sense. Particularly, reducing the mechanical sensitivity of DNM spindles reduced the accuracy in estimating head-neck to trunk position in both supine and side lying postures, but less so when head movement occurred. This result points to sensory reweighting of vestibular and neck muscle proprioceptive inputs in maintaining the acuity of head-to-trunk position sense.

To compare the effects of different neck eccentric training devices on the neck strength and endurance of aviation cadets, and to explore their roles in the prevention of neck injuries, providing a basis for introducing specialized neck training in adolescent aviation schools. Two intervention groups used a helmet-style neck training device and elastic bands for neck training, respectively, while the control group underwent regular resistance physical training without additional neck intervention. Tests were conducted on neck flexion, extension, lateral flexion, and rotation in six directions before the intervention, and after 6 and 12 weeks. Significant time and group interaction effects were found in all six directions of neck strength indicators (F-values were 4.834, 8.496, 10.359, 6.849, 3.324, 2.405, p<0.05). The neck strength in all six directions significantly increased for both intervention groups at 6 and 12 weeks (P<0.05). In the control group, a significant increase in strength was observed in all directions except for extension at 6 weeks (P<0.05), but no significant changes were observed after 6 weeks (P>0.05). A significant time and group interaction effect was also found for endurance indicators (F=6.204, P<0.01). All three groups showed a significant increase in neck endurance at 6 weeks, but no significant changes were observed in the elastic band group and the control group after 6 weeks (P>0.05); the helmet group showed significantly higher neck endurance at 12 weeks (103.55 ±47.68) seconds, (P<0.01). Both 12-week helmet-style neck training and elastic band neck training can enhance trainee neck strength and flexural endurance, with the helmet-style training showing a more significant improvement in neck endurance.

Cervistab is an electro-pneumatic device that produces flexion push-loading events in an ecological rugby position (i.e. similar to on-pitch position) to assess neck extensors muscle response to a flexion perturbation. This response is important for preventing head/neck injuries in Rugby, however there is a clear lack of validated devices in the literature. This study tested the reliability of this new device designed to investigate the extensor neck muscle response to flexion head push-loading event. Twelve healthy volunteers were tested with Cervistab in a test/retest protocol. Participants experienced push-loading events with preloading on extensors muscles at 50 % and 20 % of their maximum voluntary isometric extension strength. Muscle mechanical latency, non-reflex and reflex rates of force development were measured twice, 7 days apart. Reliability was assessed by intraclass correlation coefficient (ICC), coefficient of variation (CV), and the Bland and Altman graphical approach. For both preloading conditions, muscle mechanical latency showed good ICC values from 0.81 to 0.88 and good CV (3.5%). Non-reflex and reflex rates of force development showed good reliability with ICC ranging from 0.78 to 0.89, and moderate CV values ranging from 8.5% to 14.5%, depending on the preloading condition (20% and 50% of maximal isometric extension contraction respectively). Bland and Altman plots showed no significant fixed or proportional bias. Overall, the reliability of measurements obtained with Cervistab is good. Cervistab can be used in practice to improve our understanding of the neuromechanical factors that influence neck stability, to help prevent head/neck injuries and to guide the decision to return to play after a head or neck injury.

Abstract Introduction Fluid displacement into nuchal and peripharyngeal soft tissues while recumbent may contribute to narrowing and increased airflow resistance of the pharynx (Rph), and predispose to pharyngeal collapse in patients at risk for obstructive sleep apnea. Objectives To determine whether displacement of fluid from the lower body to the neck will increase both neck circumference and Rph in healthy subjects. Methods In 11 healthy, nonobese subjects, studied while awake and supine, leg fluid volume, neck circumference, and Rph were measured at baseline. Subjects were then randomized to a control period or to application of lower body positive pressure (LBPP) of 40 mm Hg via antishock trousers to displace fluid from the legs, after which they crossed over to the other arm. Baseline measurements were repeated at 1 and 5 min during the control and LBPP periods. Results Compared with the control period, application of LBPP caused a significant reduction in leg fluid volume (p < 0.001) and a significant increase in neck circumference (p = 0.004). Rph remained stable during the control period, but increased significantly from baseline after 1 and 5 min of LBPP (from 0.43 ± 0.10 to 0.60 ± 0.11 cm H2O/L/s, p = 0.034, and to 0.87 ± 0.19 cm H2O/L/s, p < 0.001, compared with baseline, respectively). Conclusions Fluid displacement from the legs by LBPP increases neck circumference and Rph in healthy subjects. These findings suggest the hypothesis that fluid displacement to the upper body during recumbency may predispose to pharyngeal obstruction during sleep, especially in fluid overload states, such as heart and renal failure.