The influence of different sitting postures on head/neck posture and muscle activity

Improvement in Chronic Low Back and Intermittent Chronic Neck Pain, Disability, and Improved Spine Parameters Using Chiropractic BioPhysics® Rehabilitation After 5 Years of Failed Chiropractic Manipulation: A Case Report and 1-Year Follow-Up

BACKGROUND/OBJECTIVES

We present a case documenting the successful treatment for a patient with chronic low back pain (CLBP), chronic neck pain (CNP), and decreased quality of life improving after conservative therapy. CLBP has been the leading cause of disability globally for the past few decades, resulting in decreased quality of life physically and emotionally. This case is important in the medical literature to add to studies reporting successful conservative treatment of CLBP and CNP. Triage, diagnosis, and understanding of economical and conservative therapeutics can benefit patients; providers as well as institutions and third party payors benefit from improved outcomes.

METHODS

A 39-year old male presented with severe CLBP who had experienced no long-term success with prior chiropractic spinal manipulative therapy (SMT). After symptoms began to worsen in spite of receiving SMT, the patient sought treatment for his pain, abnormal spine alignment, and poor sagittal alignment at a local spine facility. History and physical examination demonstrated altered spine and postural alignment including significant forward head posture and reduced cervical and lumbar lordosis and coronal plane abnormalities. Treatment consisted of a multi-modal regimen focused on strengthening postural muscles, specific spine manipulation directed toward abnormal full-spine alignment, and specific Mirror Image® traction aiming to improve spine integrity by realigning the spine toward a more normal position. The treatment consisted of 36 treatments over three months. All original tests and outcome measures were repeated following care.

RESULTS

Objective and subjective outcome measures, patient-reported outcomes, and radiographic mensuration demonstrated improvement at the conclusion of treatment and maintained at 1-year follow-up re-examination.

CONCLUSIONS

This case demonstrates that the CBP® orthopedic chiropractic treatment approach may represent an effective method to treat abnormal spinal alignment and posture. This study adds to the literature regarding conservative methods of treating spine pain and spinal disorders.

Impact of forward head posture correction on craniovertebral angle, neck disability, and spinal electromyography: A randomized controlled trial

BACKGROUND

Forward head posture (FHP) is a common malalignment affecting the cervicothoracic spine. This deviation is associated with neck disability and muscle imbalance.

OBJECTIVE

This study aimed to investigate the efficacy of FHP correction using regional versus comprehensive spinal programs on the craniovertebral (CV) angle, neck disability, and spinal muscle activity.

METHODS

Sixty participants with FHP were randomly assigned to receive either a cervicothoracic correction program (control group) or a cervicothoracic plus lumbopelvic program (experimental group). The CV angle, neck disability index (NDI), and normalized electromyography as a percentage of maximum voluntary isometric contraction (%MVIC) from spinal muscles were measured before and after the intervention.

RESULTS

Post-intervention, both groups showed significant improvement across time in CV angle and NDI (p < 0.001, p = 0.002). However, the between-group comparison was not statistically significant. The NDI showed significant improvement only in the experimental group (p = 0.005). The minimal clinical important difference (MCID) obtained was 6.44 for the NDI. A reduction in %MVIC over time was observed in both groups for cervical erector spinae (Right, p = 0.006, Left, p = 0.001). The between-group comparison of spinal muscle activation was not significantly different.

CONCLUSION

The study suggested that FHP management using a cervicothoracic or cervicothoracic plus lumbopelvic protocol could improve cervical posture and lower cervical muscle demand. Incorporating a lumbopelvic into the cervicothoracic protocol was more effective in reducing short-term neck pain and disability than a cervicothoracic protocol alone. A comprehensive spine program may be a clinically beneficial rehabilitation protocol for FHP to improve neck pain and disability.

Central mechanisms of muscle tone regulation: implications for pain and performance

Muscle tone represents a foundational property of the motor system with the potential to impact musculoskeletal pain and motor performance. Muscle tone is involuntary, dynamically adaptive, interconnected across the body, sensitive to postural demands, and distinct from voluntary control. Research has historically focused on pathological tone, peripheral regulation, and contributions from passive tissues, without consideration of the neural regulation of active tone and its consequences, particularly for neurologically healthy individuals. Indeed, simplistic models based on the stretch reflex, which neglect the central regulation of tone, are still perpetuated today. Recent advances regarding tone are dispersed across different literatures, including animal physiology, pain science, motor control, neurology, and child development. This paper brings together diverse areas of research to construct a conceptual model of the neuroscience underlying active muscle tone. It highlights how multiple tonic drive networks tune the excitability of complex spinal feedback circuits in concert with various sources of sensory feedback and in relation to postural demands, gravity, and arousal levels. The paper also reveals how tonic muscle activity and excitability are disrupted in people with musculoskeletal pain and how tone disorders can lead to marked pain and motor impairment. The paper presents evidence that integrative somatic methods address the central regulation of tone and discusses potential mechanisms and implications for tone rehabilitation to improve pain and performance.

Effects of Postural Changes Using a Standing Desk on the Craniovertebral Angle, Muscle Fatigue, Work Performance, and Discomfort in Individuals with a Forward Head Posture

Forward head posture is common among office workers who sit for long periods of time and is one of the main causes of neck pain. This study aimed to assess the effects of utilizing a standing desk on the craniovertebral angle, muscle fatigue, work performance, and discomfort in individuals with forward head posture. Twenty-four participants meeting the inclusion criteria were randomly assigned to either a traditional desk group (n = 12) or a standing desk group (n = 12). Each group engaged in 30 min of computer typing. To evaluate the impact of posture change using a standing desk, pre- and post-experiment discomfort surveys were conducted, and the craniovertebral angle and muscle fatigue were measured throughout the experiment. Work performance was assessed post-experiment based on the work completed by the participants. Intra-group analysis of the craniovertebral angle showed a significant decrease in the traditional desk group (p < 0.05) and a significant increase in the standing desk group (p < 0.05). When comparing the craniovertebral angle between the two groups, a significant difference was observed (p < 0.05). Additionally, significant differences in muscle fatigue, particularly in the levator scapulae muscles, were observed between the two groups (p < 0.05). The traditional desk group reported increased discomfort in the neck and shoulders (p < 0.05). These findings suggest that utilizing a standing desk can positively impact posture, reduce muscle fatigue, and alleviate discomfort in individuals with forward head posture, potentially serving as an intervention to prevent musculoskeletal disorders.

Posture Monitoring During Breastfeeding: Smart Underwear Integrated with an Accelerometer and Flexible Sensors

The position that a woman adopts during breastfeeding is important for both infant and maternal health; however, many women experience musculoskeletal pain due to poor posture during breastfeeding, which is a known factor in low exclusive breastfeeding rates. Posture monitoring is an effective intervention, but existing wearable devices do not consider the ergonomics of nursing mothers and breastfeeding scenarios. In this study, nursing underwear was developed with posture monitoring and a real-time feedback system using accelerometers and flexible bending sensors targeting the neck and upper thoracic spine. Semi-structured interviews were conducted with 12 Chinese mothers to identify key challenges and inform the design. After designing and producing the prototype, wear trials were conducted with two participants who tested both the prototype and a commercial sample while holding a 4 kg baby doll. Video recordings and questionnaires were used to assess the underwear's effectiveness. The results showed improvements in postural alignment and an increase in the frequency and duration of relaxation periods. Participants reported that the prototype surpassed the commercial sample in functionality, comfort, and aesthetics. These findings are significant for postpartum health and provide guidelines for future smart nursing garment development.

Are cervical curvature and axioscapular muscle activity associated with disability in patients with chronic nonspecific neck pain? - a cross sectional exploratory study

Purpose

To ascertain the relationship between cervical curvature, neck muscle activity and neck disability in patients with chronic nonspecific neck pain (CNNP).

Methods

Ninety participants (mean age = 27.2, female/male ratio = 7/2) with CNNP volunteered. The Neck Disability Index was used to assess neck disability. To indicate the electromyographic characteristics of the axioscapular muscles, the root mean squares and median frequencies of upper trapezius and levator scapula were used. Cervical curvature was measured with a flexible ruler.

Results

Disability of the neck was significantly correlated with curvature (r = -0.599, p < 0.001), upper trapezius root mean square (RMS) (r = 0.694, p < 0.001) and levator RMS (r = 0.429, p < 0.05). Multiple regression analysis produced a significant predictive equation that could predict disability: 33.224- 0.515 × Curvature + 0.156 × Levator RMS - 0.059 × Upper trapezius median frequency + 0.636 × upper trapezius RMS + 0.020 × levator median frequency, with R2 = 0.622.

Conclusion

Cervical curvature as well as different axioscapular muscle activity were found to be related to level of disability. These findings have implications for clinical management of CNNP.

Usability evaluation of a smart upper limb rehabilitation exercise device for individuals with disabilities

User-friendly rehabilitation exercise devices can enhance health and quality of life through the convergence of information communication and medical technology. The development of rehabilitation exercise devices accessible to individuals with disabilities is important. We aimed to investigate the convenience, safety, and effectiveness of the developed rehabilitation exercise device for individuals with disabilities. A usability evaluation of the developed rehabilitation exercise device was conducted with five rehabilitation exercise experts and six athletes with disabilities using a questionnaire, the reliability of the revised questionnaire was r=0.87. Qualitative analysis was conducted using semistructured interviews following the testing of the upper limb rehabilitation exercise device by the two user groups. In the usability evaluation survey of the developed rehabilitation exercise device, the results were very positive, with an overall score of 4.25 out of 5. The highest score was assigned to the convenience of the device, followed by the effectiveness of the exercise and the safety of the device. The developed rehabilitation exercise device allows for three types of strength improvement exercises, including isometric, isokinetic, and isotonic exercises, all within a single device. Given that it is constructed with a wire system, it can be adapted to various exercise methods, depending on the type of disability. The device can be used by both nondisabled and disabled individuals, allowing for various exercise methods. The evaluation results indicate that the proposed device is highly versatile and practical.

Comparison of mental fatigue using EEG signals and task performance in normal and slump posture adults during computer typing

OBJECTIVES

Slump sitting at workstations has been focused on by clinicians and researchers nowadays; however, there is limited evidence to date that improper positioning affects the mental state. Accordingly, the main objective of this research was to examine the impact of slump posture on mental fatigue and task performance.

METHODS

A sample of 60 participants, 30 in each group including those with normal and slump postures were recruited to perform an hour of typing on the computer. Mental fatigue through EEG and task performances were considered as outcome measures and then were analyzed statistically in the first and last 3 min of typing.

RESULTS

The EEG showed a significant increasing trend in theta rhythm at different brain regions during 60 min of typing (P < 0.05). Besides, an interaction between time and posture was observed; it can mean the increasing trend of theta rhythm is different in normal and slump posture acquired sets (P < 0.05). Interestingly the speed of typing was found to be better (P < 0.05) in the normal posture group while no difference found between the groups in terms of errors (P > 0.05).

CONCLUSION

Our results showed poor posture can induce more mental fatigue during the given task, than the normal posture. These findings have provided evidence to indicate that in addition to the peripheral and biomechanical component, the assessment of the cortex as the central component should be considered in poor posture individuals. Besides, for any possible physical therapy rehabilitation protocol for the management of poor posture, the peripheral and central components should be focused.

TRIAL REGISTRATION

Registered on the Iranian Registry of Clinical Trials on September 21, 2022, IRCT Identifier: IRCT20161026030516N2.

A LiDAR-Based Recommendation System to Improve Sitting Posture Respecting Privacy

Poor posture is becoming more widespread due to the rising number of jobs that require workers to sit for extended hours. Maintaining proper leg positioning is essential for good overall posture and long-term health. However, current monitoring methods involve multiple sensors and cameras, leading to discomfort and privacy concerns. This paper presents a privacy-preserving recommendation system using Light Detection and Ranging (LiDAR) to monitor leg positions. The system captures the horizontal leg outline at knee height and extracts domain-specific features, while a stacked autoencoder reproduces the latent representation of the leg outline. The system comprises three modules, including one-class and multi-class support vector machines, to identify 15 leg positions and reject unrecognized ones. Data from 30 healthy volunteers during work activities trained the system. When tested on new participants, the system achieved an accuracy of over 98%. In addition to monitoring leg positions while respecting privacy and ergonomics, our system alerts workers about poor leg positions and generates intuitive dashboards with posture statistics that help safety engineers identify at-risk workers and body parts. This offers a promising solution for improving desk workers' posture and reducing long-term health issues, respecting privacy.

Anatomical Guidelines and Technical Tips for Neck Aesthetics with Botulinum Toxin

Botulinum toxin can be used for various purposes to enhance neck aesthetics, addressing concerns such as platysmal bands, optimizing the cervicomental angle, preventing worsening of horizontal neckline and decolletage lines during aging, submandibular gland hypertrophy, and hypertrophied superior trapezius muscle. Understanding the anatomy of muscles such as the trapezius, platysma, and submandibular gland is crucial for achieving desirable outcomes with botulinum toxin administration. Techniques for injecting botulinum toxin into these muscles are discussed, emphasizing safety and efficacy. Specific injection points and methods are detailed for treating platysmal bands, optimizing the cervicomental angle, addressing submandibular gland hypertrophy, and managing hypertrophied superior trapezius muscle. Careful consideration of anatomical landmarks and potential complications is essential for successful botulinum toxin injections in these areas.

Effect of loupe and microscope on dentists' neck and shoulder muscle workload during crown preparation

Although there is consensus among dentists that visual aids not only improve vision but also help improve posture, evidence is scarce. This study aimed to evaluate the effect of visual aids (loupe and microscope) on the muscle workload of dentists during crown preparation on dentiform first molars in each quadrant of a phantom head, considering dentists' muscles, patients' tooth positions and surfaces. Six right-handed dentists from a single tertiary hospital participated. Surface electromyography device recorded the muscle workload of the bilateral upper trapezius, sternocleidomastoid, cervical erector spinae, and anterior deltoid during crown preparation. The results showed significantly lower workload in all examined muscles when using a microscope compared to the naked eye (p < 0.05), whereas the loupe showed reduced workload in some specific muscles. The muscle with the highest workload for all visual aids was the cervical erector spinae, followed by the upper trapezius. When analyzed by tooth surface, while the loupe did not significantly reduce overall workload compared to the naked eye for each surface, the microscope significantly reduced workload for most surfaces (p < 0.05). Therefore, during crown preparation, the workload of the studied muscles can successfully be reduced with the use of a loupe or microscope.

Neck and shoulder strains under various head flexing positions while standing and sitting with and without back support for male and female smartphone users

This study recruited 30 young participants (15 men and 15 women) to examine the smartphone usage patterns in three postures (standing, supported sitting, and unsupported sitting) and at five head angle (HA) positions (0°-40°). Cervical erector spinae (CES) and upper trapezius (UTZ) muscle activity, neck flexion (NF), gaze angle (GA), viewing distance (VD), and discomfort scores were collected. Results showed that HA and posture almost affected all responses, while CES muscle activity, NF, and VD differed between sexes. Strain in the neck and shoulder region increased with HA increase. Particularly, when the HA exceeded 20°, the discomfort scores considerably increased. Unsupported sitting should be avoided during smartphone use because of relatively poor responses in all variables. However, both standing and supported sitting have their respective benefits. Sex-related differences were typically observed in the standing position, with women tending to have lower NF but higher CES muscle activity compared with men.Practitioner summary: Although smartphones have become daily necessities, the overall quantitative neck and shoulder strain of using smartphones in different postures is rarely evaluated. We suggest that maintaining the HA within 20° is recommended because of relatively low load on the neck and shoulders. An unsupported sitting should be avoided during smartphone use.

Efficacy of head postural correction program on craniovertebral angle, scapular position, and dominant hand grip strength in forward head posture subjects: A randomized controlled trial

OBJECTIVE

Forward head posture (FHP) is a common postural disorder that alters shoulder function. This study examined the efficacy of a corrective program involving postural correction exercises (PCEs), scapular stabilization exercises (SSEs), and kinesiotaping (KT) on improving craniovertebral angle (CVA), scapular position, and dominant hand grip strength (HGS) in individuals with FHP.

METHODS

Sixty subjects (8 males and 52 females, 18-40 years old) were randomly allocated into four equal groups: Group A: received PCEs only, Group B: received PCEs and SSEs, Group C: received PCEs and KT, Group D: received PCEs, SSEs and KT. All subjects received treatment for 4 weeks (4 times/week) and postural advice. Outcome measures included cranio-vertebral angle (CVA), scapular position using Lateral Scapular Slide Test and dominant HGS using a CAMRY dynamometer that were assessed at baseline and 4 weeks post intervention.

RESULTS

Comparing all groups post training revealed that there were statistically significant increases (p < 0.05) in all measured variables (CVA, scapular position and dominant HGS) in favor of group (D).

CONCLUSION

Combination of PCEs, SSEs and KT interventions has achieved the best gains in terms of CVA, dominant HGS and regaining optimal scapular position in FHP subjects.

The influence of chair recline and head and neck position on upper trapezius activity and stiffness during seated computer work

Increasing chair recline during seated computer work may reduce the load placed on the upper trapezius (UT), a common location of pain for those with idiopathic chronic neck pain. This study determined the effect of increasing chair recline on UT stiffness and muscle activity during computer work in people with and without idiopathic chronic neck pain. Surface electromyography and ultrasound shear wave elastography were collected from three subdivisions of the UT in 15 individuals with idiopathic chronic neck pain and 15 sex-matched healthy controls. Participants sat in a standardized computer-work setup while chair recline (0°, 25°, 45°) and head and neck position (self-selected, neutral, flexed) were systematically adjusted and maintained for 2.5-min intervals. Repeated-measures ANOVAs were completed for each sex, muscle, and data type, with group (chronic neck pain, control), chair recline (0°,25°,45°), head and neck position (self-selected, flexed, neutral), and side of collected data (dominant, non-dominant) as fixed factors. Men with idiopathic chronic neck pain demonstrated greater UT stiffness in the cranial subdivision when compared to healthy men. Additionally, the 25° and 45° recline levels increased the stiffness of men's dominant UT compared to men's non-dominant UT. Women's UT was more affected by head and neck position, and a neutral head and neck position resulted in lower UT activation, but higher UT stiffness for the cranial subdivision and midway between C-7 and the acromion process. Overall, our findings suggest that the commonly suggested neutral position may not be a beneficial prompt when positioning someone during seated computer work.

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.

Effects of slouched sitting posture on clavicular and scapular orientations and movements in individuals with neck pain with scapular dysfunction

BACKGROUND

It has been suggested that sitting posture affects clavicular, scapular and spinal kinematics, however its effects in people with neck pain and scapular dysfunction remain unknown. The study aimed to determine the clavicular and scapular kinematics in different sitting postures in patients with neck pain and scapular dysfunction.

METHODS

Thirty-four participants with neck pain and scapular dysfunction were recruited into the study. Kinematics of the clavicle and scapula were recorded using motion analysis at rest and during arm elevation (at 30, 60, 90, and 120 degrees) in a slouched and upright sitting posture.

RESULTS

Compared to the upright sitting posture, the slouched sitting posture had increased clavicular protraction and elevation as well as scapular internal rotation and anterior tilt at rest and during the arm raising and lowering phases (at 30, 60, 90, and 120 degrees) (p < 0.05). The slouched sitting also had increased scapular upward rotation in the lowering phase at all angles (p < 0.05).

SIGNIFICANCE

The slouched sitting posture has a significant influence on clavicular and scapular kinematics. Awareness of good sitting posture should be encouraged in patients with neck pain and scapular dysfunction.

The Vehicle Seating Intervention Trial: Cross-Over Randomized Controlled Trial to Evaluate the Impact of 2 Car Seat Configurations on Spinal Posture

Driving posture can lead to musculoskeletal pain. Most work focuses on the lower back; therefore, we know little about automobile seat design and neck posture. This study evaluated an automobile driver seat that individualized upper back support to improve head and neck posture. Specifically, we examined the system's impact on anterior head translation with secondary outcomes of spine posture and perceptions of comfort/well-being compared with a control. Forty participants were block randomized to experience either the activated or deactivated version of the same seating system first. Participants completed two 30-minute simulated driving trials, separated by washout, with continuous measures of anterior head translation, spine posture, and pelvis orientation. Perceptions of comfort/well-being were assessed by survey and open-ended questions immediately following each condition. Small, but statistically significant decreases in anterior head translation and posterior pelvic tilt occurred with the activated seat system. Participants reported lower satisfaction with the activated seat system. Order of the 2 seat conditions affected differences in pelvis orientation and participant perceptions of comfort/well-being. An anthropometric-based seat system targeting upper back support can significantly affect head and pelvic posture but not satisfaction during simulated driving. Future work should examine long-term impacts of these posture changes on health outcomes.

Forced Straightening of the Back Does Not Improve Body Shape

BACKGROUND

Sitting for a long time causes various postural problems, such as slump sitting. It has been reported that employing a corrected sitting position while lifting the sternum is effective in improving this form of posture. We investigated how a corrected sitting posture with the lifting of the sternum is different from a forced position that is applied through the command and passive positions.

MATERIALS AND METHODS

The postural angle of 270 subjects aged 19-23 years was measured in the passive, forced, and corrected positions using a Saunders inclinometer and a Formetric 4D system.

RESULTS

As a result, the corrected position had a small range (min-max) at all angles, but the forced position and passive position had a large range (min-max). The lumbar lordosis angle in the corrected position showed positive values throughout its range (min-max), while the other groups showed negative values, which indicates the kyphotic position of the lumbar section. In addition, the percentage error in the corrected position was small, but it presented high values in the other groups. When comparing the average angles between the groups, there were substantial changes observed between the corrected position and the other groups. It was found that the corrected position with the sternum lifted, which is applied to improve slump sitting in the clinical environment, exhibited an angle that differed from that of the forced position and the passive position.

CONCLUSIONS

Our results suggest that a forced position on the command "scapular retraction" does not meet the clinical assumptions of posture correction, in contrast to the corrected position with the lifting of the sternum for the improvement of slump sitting. The accurate correction of the position of the sternum and sacrum improves the position of the spine in the sagittal plane, enabling physiological values for the kyphosis and lordosis angle parameters to be obtained. This approach combines the ease of execution and precision of the effect. The fact that this method does not require complex tools to accurately correct the body encourages the implementation of this solution in clinical practice.

Gender-based analysis of muscle activation while in a sedentary work posture

BACKGROUND

Many people work in a sitting position where they have to use their upper extremities and hands. Muscle activity in sitting position is affected by the chair height of, the height of the worktable, and the distance to the working target.

OBJECTIVE

The purpose of this study is to investigate differences in muscle activity between men and wemen at different chair heghts and working distances.

METHODS

Surface electromyography (EMG) was employed to determine the muscle activity of the upper limbs and the trunk, while an arm-stretching task was performed in a sitting position.

RESULTS

Women's muscle activity was higher than that of men in most muscles as the chair height and working distance changed.

CONCLUSIONS

As the height of the chair or the working distance was changed, muscle activity was greater in women than in men for most of the muscles analyzed. Under the same conditions, women may feel more muscle fatigue than men, so it is necessary to consider gender in the working environment.

Are Rotations and Translations of Head Posture Related to Gait and Jump Parameters?

This study assessed the relationship between head posture displacements and biomechanical parameters during gait and jumping. One hundred male and female students (20 ± 3 yrs) were assessed via the PostureScreen Mobile® app to quantify postural displacements of head rotations and translations including: (1) the cranio-vertebral angle (CVA) (°), (2) anterior head translation (AHT) (cm), (3) lateral head translation in the coronal plane (cm), and (4) lateral head side bending (°). Biomechanical parameters during gait and jumping were measured using the G-Walk sensor. The assessed gait spatiotemporal parameters were cadence (steps/min), speed (m/s), symmetry index, % left and right stride length (% height), and right and left propulsion index. The pelvic movement parameters were (1) tilt symmetry index, (2) tilt left and right range, (3) obliquity symmetry index, (4) obliquity left and right range, (5) rotation symmetry index, and (6) rotation left and right range. The jump parameters measured were (1) flight height (cm), (2) take off force (kN), (3) impact Force (kN), (4) take off speed (m/s), (5) peak speed (m/s), (6) average speed concentric phase (m/s), (7) maximum concentric power (kW), (8) average concentric power (kW) during the counter movement jump (CMJ), and (9) CMJ with arms thrust (CMJAT). At a significance level of p ≤ 0.001, moderate-to-high correlations (0.4 < r < 0.8) were found between CVA, AHT, lateral translation head, and all the gait and jump parameters. Weak correlations (0.2 < r < 0.4) were ascertained for lateral head bending and all the gait and jump parameters except for gait symmetry index and pelvic symmetry index, where moderate correlations were identified (0.4 < r < 0.6). The findings indicate moderate-to-high correlations between specific head posture displacements, such as CVA, lateral head translation and AHT with the various gait and jump parameters. These findings highlight the importance of considering head posture in the assessment and optimization of movement patterns during gait and jumping. Our findings contribute to the existing body of knowledge and may have implications for clinical practice and sports performance training. Further research is warranted to elucidate the underlying mechanisms and establish causality in these relationships, which could potentially lead to the development of targeted interventions for improving movement patterns and preventing injuries.

Clinimetric properties of a smartphone application to measure the craniovertebral angle in different age groups and positions

Background

Craniovertebral angle (CVA) alteration is a causative factor for the neck, shoulder, and temporomandibular joints disorders. Therefore, as an outcome measure for therapeutic intervention, measuring the craniovertebral angle with the Surgimap smartphone app is a cost-effective, easily accessible, and reliable tool. This study's objective was to assess the clinimetric properties of the Surgimap smartphone application with Surgimap system software to measure the Craniovertebral Angle in different age groups and positions.

Method

Ninety subjects with neck pain were randomly allocated to aged between 18 and 30 years (Group A; n = 45) and 45-60 years (Group B; n = 45). Using the Surgimap smartphone application and Surgimap system software, the craniovertebral angle was measured objectively in the sagittal plane. Intraclass correlation coefficients were used to determine validity and reliability. Receiver operating characteristic (ROC) curves and the area under the curves (AUC) were determined to distinguish participants with and without forward head posture.

Result

The result of this study shows that Smartphone Surgimap Application and Surgimap System Software correlate 0.95 and have p-values of 0.01 for diverse positions and ages. CVA measurement in the sitting position was significantly lower than in the standing position, regardless of methodology or age. Both positions demonstrated high intra-rater reliability, as evidenced by Intraclass Correlation Coefficients (ICC) between 0.972 and 0.991. The minimum detectable change (MDC) values ranged from 1.3 to 1.733, indicating high measurement accuracy. The smartphone application demonstrated outstanding diagnostic sensitivity (100.00% for Group A standing) and specificity (93.55% for Group B standing).

Conclusion

The Surgimap smartphone application is a reliable and accurate method for craniovertebral angle measurement and is useful for measuring outcomes. Also standing posture was found to be better than sitting posture while measuring the CVA.

Ultrasonographic measurements of the omohyoid muscle during shoulder muscles contraction

BACKGROUND

The main function of the omohyoid muscle is to depress and withdraw the hyoid bone. This is an integral part of the swallowing process facilitating hyoid stabilization for tongue movement. Although the muscle is inferiorly attached to the scapula bone, its function during shoulder or scapula muscles contraction has yet not been studied.

AIM

To investigate whether changes occur in omohyoid muscle morphology during shoulder muscles contraction.

METHODS

The study included 40 healthy subjects (20 males and 20 females, Mean age: 25.68 (± 2.90) years) examined via diagnostic ultrasound. Omohyoid muscle morphology measurements (thickness and cross-sectional area) during different shoulder position (0°, 90° abduction and elevation) in rest and during isomteric contraction were evaluated.

RESULTS

The omohyoid muscle was activated when the shoulder was isometrically abducted at 90° abduction. Thickness and the cross-sectional area of the lower belly increased during contractions at 90° abduction compared with a resting position at 90° (p value < 0.01). No changes occurred at 0° isometric abduction. The CSA of the muscle was found to be significantly larger (p < 0.001) during contraction at 90° abduction compared with contraction at 0° abduction.

CONCLUSION

Omohyoid muscle was most contracted during abduction position with abduction shoulder muscles isometric contraction. Changes of the scapula position might influence omohyoid muscle function.

Analysis of abnormal muscle activities in patients with loss of cervical lordosis: a cross-sectional study

BACKGROUND

This study aimed to detect the differences in cervical muscle activation patterns in people with versus without cervical lordosis and explore the possible mechanism of cervical pain originating therein.

METHODS

This cross-sectional design included 39 participants without and 18 with normal cervical lordosis. Muscular activation was measured for 5 s in both groups using surface electromyography. Subsequently, the root mean square (RMS) of muscle amplitude was obtained at the bilateral splenius capitis, upper and lower parts of the splenius cervicis, upper and lower parts of the semispinalis cervicis, sternocleidomastoid, upper trapezius, and rhomboid muscles in five cervical positions: 0° (resting), 30° of flexion, 30° of extension, 60° of extension, and upon a 1-kg load on the head in a resting posture.

RESULTS

The RMS values of the upper trapezius muscle at all postures and the rhomboid muscles at 60° of extension were significantly lower in the loss of lordosis than control group. Comparing the RMS ratio of each posture to the resting position, the ratio of the upper trapezius at flexion was significantly higher and that of the rhomboids at 60° of extension and upon loading was significantly lower in the loss of lordosis than control group. Moreover, the pattern changes in the RMS values according to posture showed a similar shape in these two muscles, and lower in the loss of lordosis than the normal group.

CONCLUSIONS

The loss of normal cervical alignment may correlate with predisposed conditions such as reduced muscle activation of the trapezius and rhomboid muscle, and may also provoke over-firing of the upper trapezius muscle, possibly increasing neck musculoskeletal pain.

TRIAL REGISTRATION

CLINICALTRIALS

gov, registration number: NCT03710785.

Prolonged slumped sitting causes neck pain and increased axioscapular muscle activity during a computer task in healthy participants - A randomized crossover study

INTRODUCTION

Sitting posture may contribute to spinal pain. Effects of postures on pain, sensitivity and muscle activity during computer tasks were investigated.

METHODS

Twenty-five healthy participants, seated at a workstation without backrest, completed four, 15-min typing tasks: A)Upright with forearm-support; B)Upright without forearm-support; C)Slumped with forearm-support; D)Slumped without forearm-support. Participants rated pain every minute on a numerical rating scale (NRS). RMS-EMG was recorded from upper/lower trapezius (UT, LT), serratus anterior and anterior/middle deltoid. At baseline and after tasks, pressure pain thresholds (PPTs) were recorded bilaterally over the head, UT, and leg.

RESULTS

All tasks caused clinically relevant increased NRS (≥2/10) compared to baseline (P < 0.001). NRS was higher in Task-D (P < 0.003) and lower in Task-B (P < 0.005) than others. PPTs did not change from baseline. Task-D caused higher UT and LT RMS-EMG (P < 0.02) than other tasks.

CONCLUSION

A 15-min task caused pain irrespective of posture with some causing larger changes than others.

Effects of Using a Shoulder/Scapular Brace on the Posture and Muscle Activity of Healthy University Students during Prolonged Typing-A Randomized Controlled Cross-Over Trial

Laptop use appears to contribute to poor working postures and neck pain among university students. Postural braces have the potential to improve upper back/neck posture and therefore might have a role as an ergonomic aid for this population. Therefore, the purpose of this study was to assess the short-term effects of scapular bracing on pain, fatigue, cervicothoracic posture, and the activity of the neck and upper-back muscles in healthy college students. A randomized controlled crossover trial was conducted to evaluate the self-reported pain and fatigue, the amplitude and median frequency of surface electromyography in neck extensors, upper trapezius, and lower trapezius, as well as the neck and shoulder sagittal alignment (measured by inertial sensors and digital photographs) during a 30-min typing task in a sample of young, healthy university students with or without a scapular brace. The brace condition resulted in significantly smaller levels of bilateral trapezius muscle activity (p < 0.01). Rounded shoulder posture was slightly better in the brace condition, but these differences were not significant (p > 0.05). There were no significant immediate differences in pain or fatigue scores, neck alignment, or the electromyographic activity of the other muscles tested between brace and non-brace conditions (all p > 0.05). However, bracing appears to immediately reduce the electromyographic activity of the lower trapezius muscles (p < 0.05). These findings shed some light on the possible advantages of scapular bracing for enhancing laptop ergonomics in this group of individuals. Future studies are warranted to evaluate the effects of different types of braces, the importance of matching the brace to the user, and the short- and long-term effects of brace use on computer posture and muscle activity.

Efficacy of stretching exercises versus transcranial direct current stimulation (tDCS) on task performance, kinematic and electroencephalography (EEG) spectrum in subjects with slump posture: a study protocol

BACKGROUND

Slump sitting is a common posture in workplaces. There is limited evidence that poor posture impacts the mental state. This study aims to investigate whether slump posture results in more mental fatigue during computer typing, compared with normal posture and also to compare the effectiveness of stretching exercises with tDCS in fatigue monitoring.

METHODS

The sample size for this study is set at 36 participants with slump posture and 36 participants with normal posture. In the first step, to find out the differences between normal and poor posture, they will be asked to perform the typewriting task for 60 min. During the first and last 3 min of typing, mental fatigue as the primary outcome using EEG signals and further measures including kinematic behavior of neck, visual analog fatigue scale, and musculoskeletal discomfort will be assessed. Post-experiment task performance will be calculated based on typing speed and typing errors. In the next step, to compare the effect of tDCS and stretching exercises on the outcome measures, the slump posture group will receive these interventions in two separate sessions before the typing task.

DISCUSSION

With the assumption of showing significant differences in terms of outcome measures between slump and normal posture groups and also by showing the possible changes of the measures, by using either tDCS as a central modality or stretching exercises as a peripheral modality; the findings may provide evidence to indicate that poor posture has adverse effect on mental state and to introduce the effective method to overcome mental fatigue and promote work productivity.

TRIAL REGISTRATION

Registered on the Iranian Registry of Clinical Trials on 21 September 2022, IRCT Identifier: IRCT20161026030516N2.

Exploring the Interaction Between Head-Supported Mass, Posture, and Visual Stress on Neck Muscle Activation

OBJECTIVE

Assess neck muscle activity for varying interactions between helmet, posture, and visual stress in a simulated "helo-hunch" posture.

BACKGROUND

Military aviators frequently report neck pain (NP). Risk factors for NP include head-supported mass, awkward postures, and mental workload. Interactions between these factors could induce constant low-level muscle activation during helicopter flight and better explain instances of NP.

METHOD

Interactions between physical loading (helmet doffed/donned), posture (symmetric/asymmetric), and visual stress (low/high contrast) were studied through neck muscle electromyography (EMG), head kinematics, subjective discomfort, perceived workload, and task performance. Subjects (n = 16) performed eight 30-min test conditions (varied physical loading, posture, and visual stress) while performing a simple task in a simulated "helo-hunch" seating environment.

RESULTS

Conditions with a helmet donned had fewer EMG median frequency cycles (which infer motor unit rotation for rest/recovery, where more cycles are better) in the left cervical extensor and left sternocleidomastoid. Asymmetric posture (to the right) resulted in higher normalized EMG activity in the right cervical extensor and left sternocleidomastoid and resulted in less lateral bending compared with neutral across all conditions. Conditions with high visual stress also resulted in fewer EMG cycles in the right cervical extensor.

CONCLUSION

A complex interaction exists between the physical load of the helmet, postural stress from awkward postures, and visual stress within a simulated "helo-hunch" seating environment.

APPLICATION

These results provide insight into how visual factors influence biomechanical loading. Such insights may assist future studies in designing short-term administrative controls and long-term engineering controls.

Société de Biomécanique Young Investigator Award 2019: Upper body behaviour of seated humans in vivo under controlled lateral accelerations

BACKGROUND

A deep understanding of human reactions and stabilization strategies is required to predict their kinematics under external dynamic loadings, such as those that occur in vehicle passengers. Low-level frontal accelerations have been thoroughly investigated; however, the human response to different lateral accelerations is not well understood. The objective of this study is to gain insight regarding the responses of seated humans to lateral perturbations from volunteer experiments in different configurations.

METHODS

Five volunteers anthropometrically comparable to the 50th-percentile American male, were seated on a sled and submitted to 21 lateral pulses. Seven configurations, each repeated three times, were investigated in this study: a relaxed muscular condition with four pulses, namely, sine and plateau pulses of 0.1 and 0.3 g in a straight spinal posture; a relaxed muscular condition with a plateau pulse of 0.3 g in a sagging spinal posture; and a braced condition with both plateau pulses in a straight spinal posture. Upper body segment kinematics were assessed using inertial measurement units.

FINDINGS

The maximum lateral bending of the head was found to differ significantly among the four acceleration pulses (p < 0.001). Braced muscles significantly reduced lateral bending compared to relaxed muscles (p < 0.001). However, no significant difference was found in lateral bending between straight and sagging spinal postures (p = 0.23).

INTERPRETATION

The study shows that not only pulse amplitude but also pulse shape influences human responses to low accelerations, while spinal posture does not influence lateral head bending. These data can be used to evaluate numerical active human body models.

Increasing physical activity in the vehicle with an interactive seating system in a male sample

An interactive seating system (IASS) was compared to a state-of-the-art massage seating system (MS) regarding the potential of reducing health risks from prolonged sitting in the vehicle. The study investigated if the systems (1) increase heart rate, which is associated with reduced metabolic and cardiovascular risks; (2) activate muscles with the potential to reduce musculoskeletal pain; (3) influence seating comfort and discomfort. The systems were compared in a passenger scenario in a laboratory study (30 male subjects). Only the use of the IASS significantly elevated the heart rate. Muscle activity showed tendencies to increase in the lower back only while using the MS. In comparison, the IASS activated all six captured muscles. Significantly less discomfort was found for the IASS compared to the MS. In comparison to the MS, the IASS showed a substantially higher potential for reducing health risks from static sitting in the vehicle.Practitioner summary: This laboratory study compared the effects of a novel automotive interactive seating system with those of a state-of-the-art massage seating system. Muscle activity, heart rate and discomfort indicated that the IASS has a significantly higher potential to reduce health risks associated with static seating in a vehicle.Abbreviations: AB: air bladder; AC: active condition; ADSS: active dynamic seating system; CLBP: chronic lumbar back pain; ECG: electrocardiography; EMG: electromyography; IASS: interactive seating system; MS: massage seating system; PC: passive condition; PDSS: passive dynamic seating system; RMS: rootmean-square; TI: time interval.

Effects of Postural Shifting Frequency on Perceived Musculoskeletal Discomfort During 1-Hour Sitting in Office Workers

OBJECTIVE

The purpose of this study was to evaluate the effects of postural shifting frequency on perceived musculoskeletal discomfort during 1 hour of sitting in healthy office workers.

METHODS

An experimental study comparing 3 different postural shifting frequencies was conducted on 60 healthy office workers who were asked to sit for an hour. The effects of 3 postural shifts (ie, 10, 20, and 30 times/h) on discomfort, measured by Borg's CR-10 scale, were compared. A seat pressure mat was used to confirm an individual's postural shift.

RESULTS

Postural shifting frequency of 10 to 30 times/h had significant effects on perceived discomfort in the neck, shoulder, and upper and lower back during 1-hour sitting. At the neck and shoulder, a postural shifting frequency of 30 times/h significantly reduced perceived discomfort compared to a postural shifting frequency of 10 times/h during 1-hour sitting. At the upper and lower back, a postural shifting frequency of 20 to 30 times/h significantly reduced perceived discomfort compared to a postural shifting frequency of 10 times/h.

CONCLUSION

Postural shifts of 30 times/h provided buffering effects on perceived musculoskeletal discomfort at the neck, shoulder, and upper and lower back.

Effect of Spinal Sagittal Alignment in Sitting Posture on Swallowing Function in Healthy Adult Women: A Cross-Sectional Study

Swallowing function is both directly and indirectly related to postures, such as head and cervical angle and body position. However, the effects of different sitting postures on oropharyngeal swallowing have not been investigated. This study aimed to investigate whether the change in thoracolumbar alignment affected the oropharyngeal swallowing. A total of 58 healthy adult women (mean age 22.2 ± 1.67 years) without dysphagia were enrolled in this cross-sectional study. Participants were positioned in three sitting postures: comfortable sitting (CS), thoracic upright sitting (TUS), and slump sitting (SS). In each sitting posture, the kyphosis index (using a flexicurve), head and cervical angles (using a digital camera), swallowing speed (100-ml water swallowing test), and oral and articulatory function [by maximum tongue pressure (MTP) and oral diadochokinesis (ODK)] were evaluated. SS showed the largest kyphosis index and was associated with a greater anterior translation of the head. Swallowing speed was significantly decreased in SS compared with CS (p = 0.002) and TUS (p = 0.020) and ODK was significantly decreased in SS compared with other postures, for both /ta/ (p = 0.004) and /ka/ (p < 0.001) syllables. Further, MTP tended to decrease in SS compared with TUS (p = 0.064). Our results suggest that changes in sitting posture with different thoracolumbar alignments affect swallowing speed and oral and articulatory function. Consequently, adjustments to reduce sitting postural kyphosis may improve swallowing speed and oral and articulatory function.

Effects of typing positions on the upper trapezius and neck extensor muscles electromyography in office employees: A single-blind cross-sectional study

BACKGROUND

Holding incorrect postures over a long period could lead to chronic nonspecific neck pain (CNNP) in office employees.

OBJECTIVE

The present study aimed to evaluate the effects of different typing positions on the activity of the neck extensor and upper trapezius (UT) muscles of office employees diagnosed with CNNP.

METHODS

This assessor-blinded cross-sectional study was performed on 22 female subjects with the mean age of 39.95±5.30 years. The neck extensors and UT muscle activities of the participants were assessed in the upright, forward, and slouching postures by electromyography (EMG). In addition, neck proprioception and the performance of the cervical stabilizer muscles were evaluated using an inclinometer and biofeedback pressure unit, respectively.

RESULTS

A significant difference was observed between the cervical erector spine (CES) and UT muscle activities in the upright, forward, and slouching typing positions (P < 0.05). In addition, a difference was observed between the upright and slouching postures in these muscles. A positive correlation was denoted between CES muscle activity in the slouching and forward postures and the activation index of neck muscles (P < 0.05). Furthermore, a significant, negative correlation was observed between the UT muscle activity in the slouching posture and neck proprioception (P < 0.05). A positive correlation was also noted between the pain index and repositioning error rates (P < 0.05).

CONCLUSION

CES muscle activity increased in a forward head posture, which could damage neck proprioception through causing early fatigue and stimulating a cumulative damage cycle.

Laptop use and muscle activity in adult females: Ground sitting has lower muscular demand than using a chair

BACKGROUND

With progressing technology in the portable computing field, laptops are now integral for work, home and social settings. Different working postures adopted by laptop users impose different loads on the relevant muscles, which can be associated with musculoskeletal discomfort in the various body regions. Some Arabic and Asian cultures adopted postures are not well investigated, particularly for the 20-30 years age-group.

OBJECTIVE

This study compared muscle activity in the cervical spine, arm, and wrist among different laptop workstation setups.

METHODS

In this cross-sectional study, 23 healthy female university students (age = 24.2±2.28 years, range 20-26 years) performed a standardized 10 minute typing task in four different laptop workstation setups: DESK, SOFA, GROUND sitting with back support, and laptop table (LAP-Tab). Differences between electromyography (EMG) muscle activity recorded in the trapezius (TR), cervical extensors (CE), deltoid (DEL), and wrist extensors (WE) were determined using one-way repeated ANOVA measures with a post-hoc Bonferroni test.

RESULTS

Significantly higher muscle activity was observed respectively in the workstations of DESK > LAP-Tab > SOFA > GROUND. Significant differences were found between WE muscle activity and the three other muscle groups (p < 0.001). There was a significant interaction between workstations and muscle activity (F(9,264) = 3.81, p < 0.001, = 0.11), where the WE and DEL muscles showed respectively higher and lower muscle activity in all setups.

CONCLUSION

Muscles showed variable activity in different workstations such that the GROUND workstation provided the minimum load, while the DESK workstation showed the maximum load on the measured muscle groups. These findings require further investigation in different cultural and gender specific groups.

Alignment of the Sternum and Sacrum as a Marker of Sitting Body Posture in Children

An analysis of literature on the methods of assuming a sitting position and the results of our own research indicated the need to search for biomechanical parameters and existing relationships that would enable a description of sitting body posture. The purpose of this paper is to analyze the relationship between the alignment of the body of sternum and sacrum and the changes in the thoracic and lumbar spine curvatures in children. The study involved 113 subjects aged 9-13 years. A planned simultaneous measurement of the angle parameters of the alignment of the body of sternum and sacrum relative to the body's sagittal axis and the angle parameters of the thoracic and lumbar spine curvatures was performed during a single examination session. The proposed markers of alignment in the corrected sitting body posture are characterized by homogeneous results. A high measurement repeatability was observed when determining the corrected body posture in the study setting. It was noted that changes in the alignment of the body of sternum and sacrum resulted in changes in the thoracic kyphosis and lumbar lordosis angle values, which may be an important component of clinical observations of sitting body posture in children. Implementing the body of sternum alignment angle of about 64° relative to the body's sagittal axis in clinical practice as one of the objectives of postural education may be the target solution for sitting body posture correction in children.

Effects of Feedback-Supported Online Training during the Coronavirus Lockdown on Posture in Children and Adolescents

(1) Background. The coronavirus pandemic had a serious impact on the everyday life of children and young people with sometimes drastic effects on daily physical activity time that could have led to posture imbalances. The aim of the study was to examine whether a six-week, feedback-supported online training programme could improve posture parameters in young soccer players. (2) Methods. Data of 170 adolescent soccer players (age 15.6 ± 1.6 years) were analyzed. A total of 86 soccer players of a youth academy participated in an online training program that included eight exercises twice per week for 45 min (Zoom group). The participants’ exercise execution could be monitored and corrected via smartphone or laptop camera. Before and after the training intervention, participants’ posture was assessed using photographic analysis. The changes of relevant posture parameters (perpendicular positions of ear, shoulder and hips, pelvic tilt, trunk tilt and sacral angle) were statistically tested by robust mixed ANOVA using trimmed means. Postural parameters were also assessed post hoc at 8-week intervals in a control group of 84 participants of the same age. (3) Results. We found a statistically significant interaction (p < 0.05) between time and group for trunk tilt, head and shoulder protrusion and for hip anteversion in the Zoom group. No changes were found for these parameters in the control group. For pelvic tilt no significant changes were found. (4) Conclusions. Feedback-based online training with two 45 min sessions per week can improve postural parameters in adolescent soccer players over a period of six weeks.

Impact of adding scapular stabilization to postural correctional exercises on symptomatic forward head posture: a randomized controlled trial

BACKGROUND

One of the most overspread postural abnormalities is forward head posture (FHP) and it is described as head projection anteriorly in relation to the trunk which appears mainly in sagittal plane. Scapular stabilization exercise (SSE) is capable of restoring each of thoracic cage and head neutral optimum position by neck and shoulder muscles interactions and through controlling scapular position and movement.

AIM

This study was conducted to investigate the impact of adding scapular stabilization (SSE) to postural correctional exercises (PCE) on symptomatic FHP.

DESIGN

The pre-post single-masking (assessor) randomized experimental trial.

SETTING

Participants with postural dysfunction in form of FHP admitted to outer clinic of the Faculty of Physical Therapy.

POPULATION

Sixty participants (20 to 35 years) with symptomatic FHP and recruited from outer clinic at faculty of physical therapy.

METHODS

Participants were allocated randomly by opaque sealed envelope to two groups who are referred from an orthopedist: Group "A" received SSE and postural correction exercises, whereas Group "B" received only postural correctional exercises; treatments were performed three times/week for 10 weeks. The craniovertebral angle, pressure pain threshold, cervical flexor and extensor muscles endurance, Arabic neck disability index, upper trapezius and sternocleidomastoid muscle root mean square during rest and activity were used to evaluate the patients' pretreatment and post-treatment.

RESULTS

Within group analysis for sixty participants reported statistical significant difference between baseline and post-treatment as P value <0.05 with more refinement in stabilization exercise group.

CONCLUSIONS

Adding SSEs to PCEs is more effective method than PCEs seldom for the management of FHP patients.

CLINICAL REHABILITATION IMPACT

Both scapular stabilization and postural correction exercise increase craniovertebral angle and pressure pain threshold (PPT) and decrease muscle activity and disability. Scapular stabilization alone increase craniovertebral angle and PPT and decrease muscle activity and disability more than postural correction exercise. In addition of statistical significant difference in all variables but there were clinical change in disability only.

Young people's low back pain and awareness of postural habits: A cross-sectional study

BACKGROUND

Young people tend to spend most of their time in activities involving inappropriate positions, which can promote musculoskeletal alterations and disorders.

OBJECTIVE

To investigate the prevalence of low back pain (LBP) in young people and analyse its associations with daily postural habits.

METHODS

Cross-sectional and retrospective study evaluating 679 Brazilian young people (15 to 18 years old), using questionnaires about LBP and awareness of postural habits. The prevalence values were calculated for the present moment, the last three months and throughout life. The Mann-Whitney U test and the Chi-square test were applied.

RESULTS

The prevalence of LBP at the present moment was 27.2%, 57.7% over the last three months and 73.9% throughout life. Boys and girls presented significantly different values, a larger number of girls manifesting pain for the three moments. The associated postural habits were: turning the body, reduction of lumbar lordosis when seated, not placing the feet on the floor, crossing the legs when sitting in the classroom and at home, sitting or lying in an inappropriate position, and distributing the body asymmetrically on the legs when standing.

CONCLUSIONS

Young people from 15 to 18 years of age show a high prevalence of low back pain. Inadequate postural habits adopted during everyday activities are associated with this complaint. These findings could contribute to the implementation of prevention and rehabilitation strategies.

Guidelines for botulinum neurotoxin injection for facial contouring

SUMMARY

The hypertrophied temporalis and masseter muscles give a muscular shaped and bulky contour to the face. Botulinum neurotoxin injection methods are commonly used for facial contouring; however, adverse effects have been reported owing to a lack of delicate anatomical information. The anatomical considerations when injecting botulinum neurotoxin into the temporalis and masseter muscles have been reviewed in the present study. Current knowledge on the localization of the botulinum neurotoxin injection point with more recent anatomical dissection and modified Sihler's staining procedures was assessed. We found that for the muscles, the injection point can be more precisely demarcated. Optimal injection sites are presented for the temporalis and masseter muscles, and the injection technique has been suggested. We propose the optimal injection sites in relation to external anatomical landmarks for the frequently injected muscles of the face to facilitate the efficiency of botulinum neurotoxin injections. In addition, these guidelines would aid in more precise practice without the adverse effects of botulinum neurotoxin.

Differences in upper body posture between individuals with and without chronic idiopathic neck pain during computerised device use: A 3D motion analysis study

BACKGROUND

Computer use is associated with poor postures and increased risk of developing neck pain. Evaluating differences in working posture of individuals with and without chronic neck pain may assist the development of strategies to lessen or prevent pain.

OBJECTIVE

To identify if upper body kinematics differs between individuals with and without chronic idiopathic neck pain during four conditions (tablet, laptop, and desktop computer sitting and standing).

METHODS

Three-dimensional (3D) motion capture measured upper body kinematics in 44 individuals with chronic idiopathic neck pain > 90 days (Cases n = 22) and without pain (Control n = 22), during a typing task under four conditions: tablet, laptop, desktop computer (sitting and standing). Differences between groups were evaluated using generalised linear mixed models.

RESULTS

Across all conditions and compared to controls, cases had significantly less flexion between their head-neck and upper trunk segments (between group mean difference 7.15°, 2.1, 12.2, p = .006), greater upper trunk flexion relative to the laboratory (-6.15°, -10.9, -1.3, p = .012), greater shoulder flexion bilaterally (left 12.35°, 6.7, 17.9, p < .001; right 13.49°, 7.9, 19.1, p < .001) and less right elbow flexion (-6.87°, -12.1, -1.7, p = .010). Approaching significance, the case group had less left elbow flexion (between group mean difference -5.36°, -10.9, 0.1, p = .056) and a smaller mean craniocervical angle for the seated desktop condition (group x condition interaction -6.37°; 95% CI -12.7, -0.1, p = .052).

SIGNIFICANCE

Individuals with neck pain consistently used different upper body postures compared to individuals without pain when working on computerised devices under varying workstation conditions. This finding suggests that people with neck pain work in potentially aggravating postures that may be associated with their pain.

Characteristics of office workers who benefit most from interventions for preventing neck and low back pain: a moderation analysis

Number of working hours, work-related psychological demands, and use of lumbar support moderate the beneficial effects of preventive interventions for neck and low back pain.

Introduction:

Neck and low back pain are significant health problem in sedentary office workers. Active break and postural shift interventions has been proved to reduce the incidence of new onset of both neck and low back pain.

Objectives:

To identify variables that moderate the effects of active breaks and postural shift interventions on the development of neck and low back pain in office workers.

Methods:

Using data from a 3-arm (active break, postural shift, and control group) cluster randomized controlled trial (N = 193), we evaluated the moderating effects of age, job position, education level, sex, perceived psychological work demands, number of working hours, and using a chair with lumbar support on the benefits of 2 interventions designed to prevent the development of neck and low back pain in office workers. Moderation analyses were conducted using the Hayes PROCESS macro, with post hoc Johnson–Neyman techniques and logistic regressions.

Results:

Significant interactions between intervention groups and 3 moderators assessed at baseline emerged. For the prevention of neck pain, the effect of the active break intervention was moderated by the number of working hours and the effect of the postural shift intervention was moderated by the level of perceived psychological work demands and the number of working hours. For the prevention of low back pain, the effect of postural shift intervention was moderated by having or not having a chair with lumbar support.

Conclusions:

The study findings can be used to help determine who might benefit the most from 2 treatments that can reduce the risk of developing neck and low back pain in sedentary workers and may also help us to understand the mechanisms underlying the benefits of these interventions.

Sensitivity of the Cervical Disc Loads, Translations, Intradiscal Pressure, and Muscle Activity Due to Segmental Mass, Disc Stiffness, and Muscle Strength in an Upright Neutral Posture

Musculoskeletal disorders of the cervical spine have increased considerably in recent times. To understand the effects of various biomechanical factors, quantifying the differences in disc loads, motion, and muscle force/activity is necessary. The kinematic, kinetic, or muscle response may vary in a neutral posture due to interindividual differences in segmental mass, cervical disc stiffness, and muscle strength. Therefore, our study aimed to develop an inverse dynamic model of the cervical spine, estimate the differences in disc loads, translations, intradiscal pressure, and muscle force/activity in a neutral posture and compare these results with data available in the literature. A head–neck complex with nine segments (head, C1–T1) was developed with joints having three rotational and three translational degrees of freedom, 517 nonlinear ligament fibers, and 258 muscle fascicles. A sensitivity analysis was performed to calculate the effect of segmental mass (5th to 95th percentile), translational disc stiffness (0.5–1.5), and muscle strength (0.5–1.5) on the cervical disc loads (C2–C3 to C7–T1), disc translations, intradiscal pressure, and muscle force/activity in a neutral posture. In addition, two axial external load conditions (0 and 40 N) were also considered on the head. The estimated intradiscal pressures (0.2–0.56 MPa) at 0 N axial load were comparable to in vivo measurements found in the literature, whereas at 40 N, the values were 0.39–0.93 MPa. With increased segmental mass (5th to 95th), the disc loads, translations, and muscle forces/activities increased to 69% at 0 N and 34% at 40 N axial load. With increased disc stiffness (0.5–1.5), the maximum differences in axial (&lt;1%) and shear loads (4%) were trivial; however, the translations were reduced by 67%, whereas the differences in individual muscle group forces/activities varied largely. With increased muscle strength (0.5–1.5), the muscle activity decreased by 200%. For 40 vs. 0 N, the differences in disc loads, translations, and muscle forces/activities were in the range of 52–129%. Significant differences were estimated in disc loads, translations, and muscle force/activity in the normal population, which could help distinguish between normal and pathological cervical spine conditions.

Corrective exercises administered online vs at the workplace for pain and function in the office workers with upper crossed syndrome: randomized controlled trial

Objective

To evaluate the effects of online-supervised versus workplace corrective exercises on neck–shoulder pain (NSP), sick leave, posture, workability, and muscular activity among office workers with the upper crossed syndrome (UCS).

Methods

We performed a parallel-group randomized control trial at Shahid Beheshti University, Tehran, Iran, assigning 36 office workers to online-supervised, workplace, and control groups (mean (SD) age 38.91 ± 3.87, 38.58 ± 7.34, 37.00 ± 8.12). Inclusion criteria were alignment alteration (forward head (≥ 45°), rounding shoulder (≥ 52°), rounding back (≥ 42°), and pain intensity ≥ 3 in neck and shoulder. The two intervention groups performed 8-week exercise program, while the control group continued usual activities. Primary (NSP and sick leave) and secondary outcomes [postural angles, workability, and muscular activity were measured by VAS, outcome evaluation questionnaire (OEQ), photogrammetry, workability index, and EMG, respectively, at the baseline and an 8-week follow-up].

Results

ANCOVA results revealed improvements for the online-supervised group versus control for NSP (P = 0.007), postural angles (P = 0.000, P = 0.001, P = 0.005), workability (P = 0.048, P = 0.042), and upper trapezius activation (P = 0.024, P = 0.016), respectively. Using paired t tests, both intervention groups improved from baseline to follow-up for NSP (P = 0.000, P = 0.002), forward head posture (P = 0.000, P = 0.000), round shoulders (P = 0.001, P = 0.031), and round back (P = 0.034, P = 0.008), respectively. Related parameters of workability (P = 0.041, P = 0.038), upper trapezius (P = 0.005, P = 0.005, P = 0.022), and serratus anterior (P = 0.020, P = 0.015) changed only in the online-supervised group.

Conclusion

Online-supervised corrective exercise seems to improve a range of parameters related to work performance. These findings are highly applicable in light of the ongoing COVID pandemic; many workers have to work from home.

Associated Risk Factors with Low Back Pain in White-Collar Workers-A Cross-Sectional Study

Objective: The purpose of the study was to compare the pressure pain threshold (PPT) of soft tissue and the curvatures of the spine in a sitting position and to estimate associated physical risk factors with low back pain (LBP) in young adults. Subjects: White-collar workers (n= 139), both women (n = 51) and men (n = 88) were separated into a control group (n = 82) and a low-intensity LBP (NRS < 3) (n = 57). Methods: The PPTs were tested utilizing the Wagner algometer. The curvatures of the spine were measured employing the photogrammetric method. In the logistic regression model, the odds ratio (OR) was estimated with ±95% confidence interval (CI) indicating the probability of the reported LBP. Results: The PPTs of soft tissue (OR = 1.1; CI = 1.02−1.19; p < 0.05) and the angle of the thoracolumbar spine in the everyday, habitual sitting position (OR = 1.19; CI = 1.05−1.34; p < 0.05) were associated with low-intensity LBP in female subjects. Additionally, the low intensity LBP were associated with the angles of the torso (OR = 1.14; CI = 1.01−1.29; p < 0.05) and the lumbosacral spine in the corrected sitting position (OR = 1.06; CI = 0.98−1.15; p > 0.05) and BMI (OR = 1.56; CI = 0.84−2.90; p > 0.05) in male subjects. Conclusion: Individual risk factors were associated with the low-intensity LBP only in females utilizing the PPT and the thoracolumbar angle in the habitual sitting position study factors. Men from the LBP group did not effectively correct the lumbosacral angle. Therefore, re-educated, self-corrected posture with specific postural training would be expected to improve proprioception in postural control capacity and result in decreasing pain.

Sagittal imbalance of the spine is associated with poor sitting posture among primary and secondary school students in China: a cross-sectional study

Background

Long-term poor posture may affect the morphological development of the spine. However, there is no definite answer as to how writing posture affects students’ spine. This study attempted to compare the sagittal curvature of the spine between sitting and standing postures in adolescents to reveal the variation rule of spinal sagittal curvature of students with learning posture, and to discover the key factors that may affect students’ spinal health.

Methods

1138 participants (male, 604; female, 534; age range, 6–18 years) from three schools in Tianjin, China, including 570 primary school students and 568 secondary school students. This study used SpineScan and PA200 Station Posture Assessment System to assess the sagittal curvature of the spine for three postures: sitting on a chair in upright position, seated at a desk while reading/writing, and standing in natural relaxed position. Analyze the difference between spine angle of the three postures and the correlation between the sagittal plane angle of the spine and body posture.

Results

The mean sagittal angle of the spine changed when the participants were in reading/writing position compared to standing position, with the lumbar lordosis angle significantly decreased (p < 0.05) and the thoracic kyphosis angle significantly increased (p < 0.05). The TKA and LLA angles were abnormal in 33 and 52% of students in reading/writing posture respectively. There was a significant correlation between sitting posture and standing spinal Angle and were positively correlated with the height of the teenager (p < 0.05). By contrast, a higher percentage of TKA and LLA subjects in the standard reading/writing posture reference range maintained normal spinal shape while standing.

Conclusions

The angle of thoracic kyphosis significantly increased from standing posture to upright sitting, reading/writing posture, while lumbar lordosis significantly decreased or even disappeared. There was a significant correlation between sagittal angle of spine in different postures. The poor sitting posture associated with sagittal angle abnormalities impact the shape of the spine such that sagittal imbalance was also observed when students in natural standing posture. Height is an important factor affecting the sitting spine shape of students.

Effects of smartphone screen viewing duration and body position on head and neck posture in elementary school children

BACKGROUND

Electronic media have become integral parts of modern life, in which prolonged screen viewing time (SVT) by children is nearly unavoidable. Prolonged use of smartphones could lead to musculoskeletal problems.

OBJECTIVES

To investigate the effect of SVT on head and neck posture during and after using smartphones for various periods of time in either standing or sitting postures.

METHODS

This observational study included 34 male children aged 5-12 years who were assigned to one of two groups based on average smartphone use duration per day: group A comprised 18 children averaging > 4 hours per day (h/day) of smartphone use, and group B comprised 16 children with < 4 h/day of smartphone use. The children's postures were photographed in standing and sitting positions while using a smartphone and 30 min after ceasing smartphone use. The head flexion, neck flexion, gaze, and craniocervical angles were measured using the software program Kinovea.

RESULTS

Significant increases were found in head flexion, neck flexion, and gaze angles. Furthermore, both groups saw a significant decrease in craniocervical angle when sitting compared to when standing, both during and 30 min after smartphone use. The head flexion, neck flexion, and gaze angles of group A were significantly higher than those of group B, and the craniocervical angle of group A was significantly lower than that of group B in both postures (p< 0.05).

CONCLUSION

SVT is associated with increased neck and head flexion posture in children, especially in a sitting position.

Online supervised versus workplace corrective exercises for upper crossed syndrome: a protocol for a randomized controlled trial

Background and objective

Musculoskeletal disorders (MSDs) including upper crossed syndrome (UCS) are considered as the leading cause of work-related issues worldwide among office workers. Therefore, the present study aims to evaluate the effect of workplace-based versus online-supervised home-based corrective exercises among office workers with UCS.

Methods and design

To this end, 45 subjects within the age range of 30–45 years are randomly assigned to three groups in the present parallel-group, randomized control trial using a pretest-posttest design. These groups include the subjects who receive online-supervised exercise and workplace exercise containing three sessions of intervention for 8 weeks and the control group receives no intervention while performing routine activities. The primary outcome variables are neck-shoulder pain (NSP) and consequent sick leave due to NSP, followed by alignment, workability, and the surface electromyography of upper, middle, and lower trapezius (UT, MT, and LT), sternocleidomastoid (SCM), and serratus anterior (SA) as the secondary variables.

Discussion

The present study seeks to assess the effect of workplace versus online-supervised corrective exercise interventions among 45 office workers suffering from UCS. It is expected to improve and reduce the related symptoms including postural malalignment and imbalance muscles after 8 weeks of corrective exercises. If effective, the findings may lead to adherence and work performance among the office workers, and individuals subjected to UCS can use the benefits of an online-supervised intervention. In addition, the findings may be useful in different workplaces as the evidence for employers to benefit from the reduction in the related costs and side effects of work-related neck/shoulder disorders including work disability, productivity loss, time expense, social insurance, work absenteeism, and treatment costs. Finally, clinicians and corrective exercise therapists can consider it as a clinical based-evidence intervention for their further actions.

Trial registration

Iranian Registry of Clinical Trials IRCT20200729048249N1. Registered on 5 October 2020 (https://en.irct.ir/user/trial/49992/view)

Do stool types have an influence on cervicothoracic muscle activity and cervicothoracic posture among dentists/dental students?

It has been shown that the type of stool influences lumbar posture and muscle activity during dental work. Studies investigating the effect on cervicothoracic muscle activity and posture are scarce though. The present study investigated the effect of different stool types on cervicothoracic muscle activity and posture during a dental procedure. Twenty five participants completed a simulated periodontal screening whilst sitting on the Ghopec, Salli MultiAdjuster saddle and A-dec dental stool. Muscle activity of M. Splenius Capitis, M. Sternocleidomastoideus, M. Trapezius Pars Descendens and M. Trapezius Pars Ascendens was measured using surface electromyography. Cervicothoracic posture was evaluated by means of a strain gauge (BodyGuard™) fixed between C5 and T2. No differences in muscle activity and posture were found between the three stools. Although the type of stool influences lumbar posture and muscle activity, it seems these differences are not continued at the cervicothoracic region.

Effectiveness of Combined Stretching and Strengthening Exercise Using Rehabilitation Exercise System with a Linear Actuator and MR Damper on Static and Dynamic Sitting Postural Balance: A Feasibility Study

Postural imbalance induced by prolonged sitting can be improved by exercise therapy. The aim of study was to evaluate the influence of combined stretching and strengthening exercise using rehabilitation exercise system with a linear actuator and MR damper on static and dynamic sitting postural balance. Twelve subjects who sit almost 10 h a day participated in this study. The rehabilitation exercise system with a linear actuator and MR damper was manufactured to provide stretching and strengthening exercise. All subjects were asked to perform an exercise program that was designed to enhance postural balance by stretching the tight muscle and strengthening the weakened muscle. Body pressure distributions were analyzed for mean force and mean pressure using a seat sensor system. Trunk muscle activities were measured by attaching surface electrodes to the thoracic erector spinae, lumbar erector spinae, and lumbar multifidus muscle. All data were divided into two regions (dominant and non-dominant side) under four conditions: no pelvic tilt, lateral pelvic tilt, anterior pelvic tilt, and posterior pelvic tilt. Body pressure distributions and trunk muscle activities were compared between before and after performing exercise under static and dynamic sitting conditions. Both in static and dynamic sitting conditions, there were significant differences in body pressure distributions and trunk muscle activities between the DS and NDS before performing the exercise (p < 0.01). After performing exercise, the body pressure distributions increased on the dominant side while those decreased on the non-dominant side significantly (p < 0.01). In addition, the activities of all trunk muscles on the non-predominant side increased significantly (p < 0.01 and p < 0.05). These results showed that postural balance was improved by decreasing the differences in body pressure distribution and trunk muscle activity between the dominant and non-dominant side after performing exercise. From the results of this study, we concluded that the rehabilitation exercise system with a linear actuator and MR damper is suitable for providing combined stretching and strengthening exercise, and it could be helpful to maintain correct posture by enhancing postural balance during sitting.