Translation, Cross-Cultural Adaptation, and Validation of the Persian Version of the Harris Hip Score.

Background: The Harris hip score (HHS), a self-administered questionnaire, is widely used to evaluate hip pathology affecting health-related quality of life and physical function. This study's purpose was HHS translation to Persian (HHS-Pr) and validation in patients with different hip pathologies. Methods: Translation and cultural adaptation followed existing guidelines. Hip pathology patients (n = 151) completed the HHS, 12-Item Health Survey, and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Criterion validity was determined from comparisons between the HHS measures and the different corresponding WOMAC domains. Internal consistency used Cronbach's alpha (α), content validity the "content validity index," and floor/ceiling effect the end-range 15%. Test-retest reliability used the intraclass correlation coefficient (subsample n = 30) at 3-7 days that compared baseline with a repeated measure. Measurement precision and change sensitivity used longitudinal assessment (subgroup n = 30) from the standard error of the measurement and minimal detectable change. Results: Cross-cultural adaptation required minor wording changes. The mean HHS-Pr was 57.77 ± 19.69. Criterion validity was significant with the WOMAC (r = -0.76) and 12-Item Health Survey Physical Component Summary (r = 0.47). Internal consistency was high before (α = 0.75) and after standardization (α = 0.86). Content validity was satisfactory (content validity index = 0.88). No floor/ceiling effects were found. Test-retest reliability (intraclass correlation coefficient = 0.85) was excellent, as was standard error of the measurement (raw score = 5.8) and minimal detectable change (raw score = 11.4). Conclusions: The HHS-Pr demonstrated adequate validity, reliability, and sensitivity to change. These psychometric properties sufficiently measure functional status in patients with hip pathologies in a Persian-speaking population.

Developing a shortened spine functional index (SFI-10) for patients with sub-acute/chronic spinal disorders: a cross-sectional study.

BACKGROUND: Brief whole-spine patient-reported outcome measures (PROMs) provide regional solutions and future directions for quantifying functional status, evidence, and effective interventions. The whole-spine regional Spine Functional Index (SFI-25) is used internationally in clinical and scientific contexts to assess general sub-acute/chronic spine populations. However, to improve structural validity and practicality a shortened version is recommended. This study developed a shortened-SFI from the determined optimal number of item questions that: correlated with criteria PROMs being highly with whole-spine, moderately with regional-spine, condition-specific and patient-specific, and moderately-low with general-health and pain; retained one-dimensional structural validity and high internal consistency; and improved practicality to reduce administrative burden. METHODS: A cross-sectional study (n = 505, age = 18-87 yrs., average = 40.3 ± 10.1 yrs) of sub-acute/chronic spine physiotherapy outpatients from an international sample of convenience. Three shortened versions of the original SFI-25 were developed using 1) qualitative 'content-retention' methodology, 2) quantitative 'factorial' methodology, and 3) quantitative 'Rasch' methodology, with a fourth 'random' version produced as a comparative control. The clinimetric properties were established for structural validity with exploratory (EFA) and confirmatory (CFA) factorial analysis, and Rasch analysis. Criterion validity used the: whole-spine SFI-25 and Functional Rating Index (FRI); regional-spine Neck Disability Index (NDI), Oswestry Disability Index (ODI), and Roland Morris Questionnaire (RMQ), condition-specific Whiplash Disability Questionnaire (WDQ); and patient-specific functional scale (PSFS); and determined floor/ceiling effect. A post-hoc pooled international sub-acute/chronic spine sample (n = 1433, age = 18-91 yrs., average = 42.0 ± 15.7 yrs) clarified the findings and employed the general-health EuroQuol-Index (EQ-5D), and 11-point Pain Numerical Rating Scale (P-NRS) criteria. RESULTS: A 10-item SFI retained structural validity with optimal practicality requiring no computational aid. The SFI-10 concept-retention-version demonstrated preferred criterion validity with whole-spine criteria (SFI-25 = 0.967, FRI = 0.810) and exceeded cut-off minimums with regional-spine, condition-specific, and patient-specific measures. An unequivocal one-dimensional structure was determined. Internal consistency was satisfactory (α = 0.80) with no floor/ceiling effect. Post-hoc analysis of the international sample confirmed these findings. CONCLUSION: The SFI-10 qualitative concept-retention version was preferred to quantitative factorial and Rasch versions, demonstrated structural and criterion validity, and preferred correlation with criteria measures. Further longitudinal research is required for reliability, error, and responsiveness, plus an examination of the practical characteristics of readability and administrative burden.

Translation, cultural adaptation and assessment of psychometrics properties of the Extended Version of the Nordic Musculoskeletal Questionnaire (NMQ-E) in Persian language speaking people.

BACKGROUND: To translate and cross-culturally adapt the Extended Version of the Nordic Musculoskeletal Questionnaire (NMQ-E) into Persian (NMQ-E-P) and evaluate the psychometric properties in a general population with different occupational tasks across nine body regions. METHODS: This cross-sectional study was designed according to the standard guidelines and the COSMIN checklist. The NMQ-E-P was achieved through forward and backward translation methods and consensus to produce the final draft. A Persian-speaking population (n = 571, age 38.24 ± 7.65 years, female = 46.2%) was recruited from industries and office workers with three occupational task inclusion criteria: assembly, office, and lifting. Psychometric properties included validity for face (from confirmed clarity, simplicity, and readability), content (via the content validity index); and construct (through known group validity); additionally, the properties of internal consistency (Cronbach's α); and test-retest reliability (Kappa coefficient of agreement) were considered. RESULTS: No significant issues during the translation process were found. The NMQ-E-P showed adequate internal consistency for all regions (α ≥ 0.87). The test-retest reliability was examined with Kappa agreement correlation coefficient and all items, except ankle regions, showed very good agreements (Kappa coefficient = 0.87-1.0). Excellent ICC values were obtained for quantitative variables (ICC > 0.88) and good construct validity was revealed (p < 0.001). CONCLUSION: The Persian version of the NMQ-E has very good validity and reliability and can be used by researchers and professionals to evaluate the prevalence of MSDs in nine body regions simultaneously.

Smartphone addiction prevalence, patterns of use, and experienced musculoskeletal discomfort during the COVID-19 pandemic in a general Iranian population.

BACKGROUND: Smartphone usage is an essential everyday tool in Iran, however problematic use has escalated and become a concern for the Iranian health policy system, particularly during and following the COVID-19 Pandemic. This study's aim was investigation of the prevalence of smartphone addiction, patterns of use, and the relationship to specific demographic characteristics and associated musculoskeletal disorders during the COVID-19 pandemic. METHODS: A descriptive-analytical correlational study recruited participants from a population of convenience (n = 2344) who were smartphone owners with > 1 year of use. For demographic information an electronic self-report questionnaire collected age, sex, marital status, usage for daily hours, and patterns. To assess addiction levels, the 'Smartphone Addiction Scale-short version' (SAS-SV) patient-reported outcome measure was used (cut-off = 31). For experienced discomfort, the Extended Nordic Musculoskeletal Questionnaire (ENMQ) was used. RESULTS: The participants (female = 66.6%, n = 1561, mean age = 29.07 ± 12.34 years, range 6-60 years) smartphone use averaged 5.75 ± 3.44 h/day. The general prevalence of smartphone addiction was 46.16% (females = 46.06%, males = 46.36%; married = 44.5%, single = 47.63%). School students had the greatest addiction (53.2%) and those with a higher education to or above a Master's degree were the lowest (39.38%). The highest pattern of use was for social networks at 89.1% of participants (female = 88.34%, male = 90.54%). The areas of highest reported discomfort were the eyes (43.5%) and neck (43.3%). A significant correlation was found between smartphone addiction and hours of daily usage, and the amount of usage increased during the COVID-19 pandemic period. CONCLUSION: A high level of smartphone addiction in the Iranian population was found to have occurred during the COVID-19 pandemic. Those most affected were unmarried individuals and school students, with the predominant areas being the eyes and neck. Health decision-makers should consider these findings when developing recommendations and plans for public health, particularly those focused on students.

Structured Multidisciplinary work Evaluation Tool (SMET) questionnaire: Translation, cultural adaptation and psychometric evaluation of the Persian version.

BACKGROUND: To assess relevant environmental conditions in any work-setting requires a multidisciplinary perspective that is practical, valid, and reliable. This includes the physical, environmental, and psychosocial risk-factors. The Structured Multidisciplinary work Evaluation Tool (SMET) questionnaire simultaneously considers multiple work-related demands. OBJECTIVE: This study translated and culturally adapted the SMET into Persian and evaluated its psychometric properties in Persian industrial workers. METHODS: Cross-sectional translation and cross-cultural adaptation in five standardized phases. A convenience sample (n = 211) recruited from an industrial-occupation setting completed: the SMET; and the Rapid Upper Limb Assessment (RULA), and National Aeronautics and Space Administration Task Load Index (NASA-TLX) criteria; plus light and noise levels were concurrently assessed. Psychometric properties included: validity, with face (from confirmed language clarity, simplicity, and readability), content (via the content validity index, CVI, for equivalency and relevancy), criterion (through Pearson's r correlation with relevant criteria), and construct (through known group validity between participants with/without work-related musculoskeletal disorders, WMSDs); internal consistency (Cronbach's α); and test-retest reliability (intraclass correlation coefficient, ICC2.1). RESULTS: Validity was confirmed with: face through the adaptation; content from suitable CVI values for items (CVI range = 0.78-1.0) and scale-total (CVI = 0.86); criterion from SMET associations with levels for light (r = - 0.42) and noise (r = 0.21), plus RULA (r = 0.42) and NASA-TLX (r = 0.39); and construct through participants with WMSD having significantly higher SMET total-scores (p = 0.01). Internal consistency (α= 0.89) and reliability (ICC2.1 = 0.87) were acceptable and strong. CONCLUSION: This study indicated that the SMET Persian version had acceptable psychometric properties in an industrial occupational setting. Further investigation in longitudinal populations is recommended.

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.

Cross Cultural Adaptation and Psychometric Evaluation of the Short Version of Smart Phone Addiction Scale in the Persian Language.

Objective: The addiction pattern of smartphone usage has increased concerns about potential complications. The Smartphone Addiction Scale (SAS), a self-administered questionnaire, evaluates smartphone usage and dependency. The study's purpose was to translate and culturally adapt the SAS short-version into the Persian language (SAS-SV-Pr), and evaluate its psychometric properties. Method : The SAS-SV translation used standardized procedures that involved double-forward and backward translations. A convenience sample, from three medical universities in the city of Teheran (n = 250 students), was recruited to complete the SAS-SV and the Internet Addiction Test (IAT). The content validity index (CVI) and the floor and ceiling effect were considered to evaluate content validity. To evaluate internal consistency and test-retest reliability, Cronbach's Alpha and the Intra-class Correlation Coefficient (ICC2.1) were utilized respectively. Criterion validity was measured by calculating Pearson's correlation coefficient for the total scores of SAS-SV-Pr and IAT (Pearson's r correlation coefficient). Construct validity was evaluated using exploratory factor analysis (EFA) and ratified with confirmatory factor analysis (CFA). Results: During translation and cultural adaptation, only minor wording changes were performed. The correlation between the SAS-SV-Pr and IAT was good (r = 0.57), which determined validity. There was high internal consistency (α = 0.88), split-half reliability (0.84), composite reliability (CR) (0.78) and test-retest reliability (ICC (2.1) = 0.89). Subsequent EFA demonstrated an ambiguous factor structure, being border-line between one- and two-factors, which explained 50.28% of total variance. The CFA confirmed that the two-factor solution was preferred. Our data did not show floor or ceiling effects. Conclusion: The Persian SAS-SV is a two-factor structure outcome measure to evaluate the dependency of smartphone users. It has demonstrated satisfactory psychometric properties for validity, reliability and factor structure, and is suitable for screening and research aims among Persian subjects.

Relationships between cervical sagittal posture, muscle endurance, joint position sense, range of motion and level of smartphone addiction.

BACKGROUND: Frequent smartphone use in a pathological way forces the user to adopt a compromised posture. This gradually results in changes to both the postural and musculoskeletal systems. This study's objectives were evaluation of head posture, muscle endurance, neck range of motion (ROM) and joint position sense in two separate smartphone user groups, one 'Addicted', the other 'Non-Addicted'. METHODS: A sample of convenience (n = 60) was recruited from medical students (age 24.57 ± 4.38, 53.3% male) with a history of smartphones use > 2 h/day for 1-year. Based on the cut-off values of the smartphone addiction scale-short version (SAS-SV), participants were entered into each group (cut-off for male ≥ 31, female ≥ 33). Neck muscle endurance time, joint position error and cervical ROM, along with forward head posture parameters of craniovertebral angle (CVA), shoulder angle (SA), sagittal head angle (SHA) and forward head distance (FHD)) were evaluated. A Mann-Whitney test and Spearman correlation coefficient were used to determine the difference between groups and the correlations between variables. RESULTS: The difference between 'Addicted' and 'Non-Addicted' groups was confirmed by the values for SAS-SV scores (25.23 ± 5.5 versus 43.9 ± 6.61) (p < 0.001). There were statistically significant differences between groups for the CVA and FHD parameters (p < 0.001). Further, the neck extensor muscle endurance (97 ± 3.79 versus 74.86 ± 2.23 s), was significantly different between groups (p = 0.010) but not after Bonferroni correction. There was no notable difference in the neck flexor muscle endurance, joint position error, SA, and SHA parameters between groups (p > 0.05). CONCLUSIONS: There is a positive correlation between smartphone addiction and both decreased extensor muscle endurance and changes in neck postural alignment.

Smartphone addiction in children: patterns of use and musculoskeletal discomfort during the COVID-19 pandemic in Iran.

BACKGROUND: Smartphone use has increased significantly, especially during the period of global pandemic caused by the novel SARS-CoV2 coronavirus (COVID-19). Concurrently, smartphone addiction is a growing social problem in children and adolescents with the consequence of adverse health outcomes. This study assessed the prevalence of smartphone addiction, patterns of use, and the experienced body-region discomfort among Iranian school students during the COVID-19 pandemic. METHODS: A cross-sectional study with students from grades 1-9 recruited n = 585 participants (mean age = 14.49 (2.26 years); female = 65.8%). Data were collected from parents and students through the online 'Smartphone addiction scale-short version' (SAS-SV), self-reported demographic questionnaires, and extracts of the Nordic musculoskeletal questionnaire for the evaluation of musculoskeletal disorders. RESULTS: The prevalence rate of smartphone addiction (53.3%) was relatively high in the overall sample. Participants spent 6.85 (4.62) hours per day on their smartphones, which had increased 53.86% relative to the pre-pandemic period. The primary smartphone uses were for social networking (77.9%), web-surfing (53.3%), and camera activities (50.9%). There was a positive correlation between smartphone addiction as assessed with the SAS-SV and daily use time (r = 0.34, p < 0.001), and the percentage of change relative to the pre-pandemic period (r = 0.26, p < 0.001). Discomfort related to smartphone use was mostly reported as present in the eyes (39.7%) and neck (39.1%). A positive correlation was found (p < 0.001) between smartphone addiction and discomfort in the eyes, neck, wrists, shoulders, and upper-back. CONCLUSION: The more frequent usage of smartphones by students during the Covid-19 pandemic were associated predominantly with discomfort to the eyes and neck. Parents should consider the complications of musculoskeletal and postural changes during the child's future years and pay particular attention to the individual's patterns of smartphone use with an emphasis on posture and usage that reduces discomfort to the eyes and the musculoskeletal system, particularly the neck.

Independent risk factors of carpal tunnel syndrome: Assessment of body mass index, hand, wrist and finger anthropometric measurements.

BACKGROUND: The most prevalent neuropathy in the upper extremity is carpal tunnel syndrome (CTS). A variety of related risk factors such as biomechanical exposures, body mass index (BMI), sex and hand shape are reported to be related to CTS. OBJECTIVE: We aimed to identify the role of BMI, hand, wrist and finger anthropometric dimensions in the development of CTS, and to compare these measured variables between control and CTS participants. METHODS: A cross-sectional, case control study (n = 240, CTS = 120, controls = 120) with participants recruited from a convenience sample diagnosed with CTS and referred for anthropometric measurements. The control participants were matched by age and sex. The body height, weight, hand width, hand length, wrist depth, wrist width, wrist circumference, and finger length were measured. Hand, wrist and finger indices, hand to height ratio, and BMI were calculated. Mean values of all dimensions were compared between cases and controls, and the role of independent risk factors were determined by logistic regression analysis. RESULTS: The mean BMI, age, weight, sex and height were not significant between the two groups. Among the measured dimensions and calculated indices the significantly different variables between two groups were the wrist width, wrist depth, wrist circumference, hand index, hand to height index, and wrist index. Regression analysis showed that the wrist index (ß=-1.7, p = 0.0001), wrist depth (ß=0.25, p = 0.0001) and wrist width (ß=0.21, p = 0.0001) were the strongest factors in CTS development in the sample. CONCLUSION: Wrist parameters have a strong role in predicting the development of CTS, while BMI was not confirmed as an independent risk factor.

Cross-cultural adaptation, reliability, and validity of the Persian version of the Lower Limb Functional Index.

BACKGROUND: the Lower Limb Functional Index (LLFI) is a regional patient reported outcome measure (PROM) for evaluation of lower limb musculoskeletal functional status. No Persian-language (LLFI-Pr) version is available. OBJECTIVES: LLFI translation and cross-cultural adaptation to Persian and psychometric property evaluation. STUDY DESIGN: prospective diagnostic assessment. METHODS: to establish the LLFI-Pr face and content validity, double forward-backward translation protocols were used plus cognitive interviews and the 'content validity index'(CVI). Psychometric properties were determined from a convenience sample (n = 307, age 47.18 ± 11.52 years, female = 58.3%) that concurrently completed the LLFI-Pr and Persian Lower Extremity Functional Scale (LEFS-Pr). Test-retest reliability (ICC2,1, sub-sample, n = 64) was determined during a non-intervention period of 3-7 days. Internal consistency used Cronbach's Alpha (α), error used MDC90/95 from the SEM, and construct validity used Pearson's r between the LLFI-Pr and LEFS-Pr. Construct validity used exploratory factor analysis (EFA, suppression = 0.30) with non-Gaussian distribution protocols. RESULTS: psychometric properties were high for test-retest reliability (ICC2,1 = 0.90) and internal consistency (α = 0.77), moderate for construct validity (r = 0.63), with no floor or ceiling effects, error found SEM = 1.60, MDC90 = 3.7% and MDC95 = 4.42%. A two-factor (EFA) structure (total-variance = 22.01%), that consequently cannot be summated, was determined where five-items failed consistent factor-loading leaving a 20-item version with a high original-LLFI total-equivalency (r = 0.97). However, the general/region-specific item-ratio reduced from the recognized 60/40 ratio to 50/50. CONCLUSION: the 20-item LLFI-Pr is a valid two-factor solution with sound psychometric properties for research and clinical Persian-language populations with lower limb disorders.

Anthropometric data of an elderly Iranian population provides insights for system design.

BACKGROUND: Anthropometric data should be considered for each major population age category, specifically because of the dimension changes occurring during ageing. In elderly subjects, the physical activities and their capabilities become limited. Therefore anthropometric reference data for equipment and system designs is necessary. OBJECTIVES: The aim of the study was to collect data for the body dimensions of an elderly Iranian population and evaluate the related gender and age correlations. METHODS: Nineteen body dimensions were manually measured on a sample size of 317 subjects (167 male and 150 female) from four provinces of Iran. A pilot preliminary test for assessing test-retest reliability on ten body dimensions using the Intraclass Correlation Coefficient (ICC2 :1)  was performed. Descriptive statistics were reported based on gender and independent samples t-tests to compare the anthropometric dimensions of both genders and age. RESULTS: Results indicated higher dimensions in males, except for hip-breadth (p = 0.87). In all subjects, increasing age corresponded with: decreased standing shoulder height, eye height, and elbow height; and with sitting height and sitting knee height; while hip-breadth increased. Reliability was acceptable (ICC2.1 >0.88). In the elderly, as with adult subjects, there are significant gender differences in body dimensions, and this should be considered in equipment and system design. Furthermore, this study demonstrated both genders differences and the consequences of aging. CONCLUSIONS: From this pilot data, product designers can consider the anthropometric characteristics for elderly Iranian subjects for equipment and system design.

Trunk Dynamic Stability Assessment for Individuals With and Without Nonspecific Low Back Pain During Repetitive Movement.

OBJECTIVE: This study aimed to employ nonlinear dynamic approaches to assess trunk dynamic stability with speed, symmetry, and load during repetitive flexion-extension (FE) movements for individuals with and without nonspecific low back pain (NSLBP). BACKGROUND: Repetitive trunk FE movement is a typical work-related LBP risk factor contingent on speed, symmetry, and load. Improper settings/adjustments of these control parameters could undermine the dynamic stability of the trunk, hence leading to low back injuries. The underlying stability mechanisms and associated control impairments during such dynamic movements remain elusive. METHOD: Thirty-eight male volunteers (19 healthy, 19 NSLBP) enrolled in the current study. All participants performed repetitive trunk FE movements at high/low speeds, in symmetric/asymmetric directions, with/without a wearable loaded vest. Trunk instantaneous rotation angle was computed for each trial to be assessed in terms of local and orbital stability, using maximum finite-time Lyapunov exponents (LyEs) and Floquet multipliers (FMs), respectively. RESULTS: Both groups demonstrated equivalent competency in terms of trunk control and stability, suggesting functional adaptation strategies may be used by the NSLBP group. Wearing the loaded vest magnified the effects of trunk control impairment for the NSLBP group. The combined presence of high-speed and symmetrical FE movements was associated with least trunk local stability. CONCLUSION: Nonlinear dynamic techniques, particularly LyE, are potentially effective for assessing trunk dynamic stability dysfunction for individuals with NSLBP during various activities. APPLICATION: This work can be applied toward the development of quantitative personalized spinal evaluation tools with a wide range of potential occupational and clinical applications.

Cross-cultural adaptation, reliability, and validity of the work role functioning questionnaire 2.0 to Persian.

PURPOSE: To translate and cross-culturally adapt, the Work Role Functioning Questionnaire 2.0 to Persian (WRFQ-Pr), and evaluate reliability and validity. MATERIAL AND METHODS: Standardized protocols were followed including forward-backward translation then synthesis/consolidation. Subsequent pilot investigation of the draft WRFQ-Pr (n = 50, male = 68%, age = 33.5 ± 7.3 years) tested the alternative wording and determined face and content validity through readability, understandability, interpretation, and cultural relevance. Participants (n = 288) were recruited from a convenience sample to assess: construct validity through exploratory factor analysis (EFA) using Promax rotation and maximum least squares extraction; and internal consistency using Cronbach's α coefficient. Test-retest reliability was evaluated from the intraclass correlation coefficient (ICC2.1). RESULTS: The forward-backward translation was achieved with eight items (1,3,4,5,9,11,12,22) modified and reformulated due to idiomatic issues. Internal consistency for the subscales ranged from α = 0.87-0.95, and the test-retest reliability was ICC(2,1)=0.92 (CI: 0.89-0.95). The EFA showed a four-factor solution, being identical to the original version, however items 20-22 loaded with items 23-26 in one factor, which was re-named "flexibility and social demand." One item (#26) did not load above the required 0.30 threshold and was removed from the WRFQ-Pr. No floor or ceiling effects were found. CONCLUSIONS: The WRFQ translation and cross-cultural adaptation to Persian (WRFQ-Pr) was performed successfully. The determined properties of reliability and validity were comparable to those of the original English version.IMPLICATIONS FOR REHABILITATIONThe WRFW can simultaneously evaluate the health status of the worker, the existence of impairments, the involved factors in creating ability/disability at work, and the outcome of the interventions.There is no instrument available for the Persian-speaking population to evaluate related disability at work and the condition of return to work after a rehabilitation intervention.The WRFQ was translated and culturally adapted into Persian.The WRFW-Pr demonstrated excellent internal consistency, test-retest reliability and a four-factor structure.

Slacklining: A narrative review on the origins, neuromechanical models and therapeutic use.

Slacklining, the neuromechanical action of balance retention on a tightened band, is achieved through self-learned strategies combining dynamic stability with optimal energy expenditure. Published slacklining literature is recent and limited, including for neuromechanical control strategy models. This paper explores slacklining's definitions and origins to provide background that facilitates understanding its evolution and progressive incorporation into both prehabilitation and rehabilitation. Existing explanatory slacklining models are considered, their application to balance and stability, and knowledge-gaps highlighted. Current slacklining models predominantly derive from human quiet-standing and frontal plane movement on stable surfaces. These provide a multi-tiered context of the unique and complex neuro-motoric requirements for slacklining's multiple applications, but are not sufficiently comprehensive. This consequently leaves an incomplete understanding of how slacklining is achieved, in relation to multi-directional instability and complex multi-dimensional human movement and behavior. This paper highlights the knowledge-gaps and sets a foundation for the required explanatory control mechanisms that evolve and expand a more detailed model of multi-dimensional slacklining and human functional movement. Such a model facilitates a more complete understanding of existing performance and rehabilitation applications that opens the potential for future applications into broader areas of movement in diverse fields including prostheses, automation and machine-learning related to movement phenotypes.

Slacklining as therapy to address non-specific low back pain in the presence of multifidus arthrogenic muscle inhibition.

Low back pain (LBP) represents the most prevalent, problematic and painful of musculoskeletal conditions that affects both the individual and society with health and economic concerns. LBP is a heterogeneous condition with multiple diagnoses and causes. In the absence of consensus definitions, partly because of terminology inconsistency, it is further referred to as non-specific LBP (NSLBP). In NSLBP patients, the lumbar multifidus (MF), a key stabilizing muscle, has a depleted role due to recognized myocellular lipid infiltration and wasting, with the potential primary cause hypothesized as arthrogenic muscle inhibition (AMI). This link between AMI and NSLBP continues to gain increasing recognition. To date there is no 'gold standard' or consensus treatment to alleviate symptoms and disability due to NSLBP, though the advocated interventions are numerous, with marked variations in costs and levels of supportive evidence. However, there is consensus that NSLBP management be cost-effective, self-administered, educational, exercise-based, and use multi-modal and multi-disciplinary approaches. An adjuvant therapy fulfilling these consensus criteria is 'slacklining', within an overall rehabilitation program. Slacklining, the neuromechanical action of balance retention on a tightened band, induces strategic indirect-involuntary therapeutic muscle activation exercise incorporating spinal motor control. Though several models have been proposed, understanding slacklining's neuro-motor mechanism of action remains incomplete. Slacklining has demonstrated clinical effects to overcome AMI in peripheral joints, particularly the knee, and is reported in clinical case-studies as showing promising results in reducing NSLBP related to MF deficiency induced through AMI (MF-AMI). Therefore, this paper aims to: rationalize why and how adjuvant, slacklining therapeutic exercise may positively affect patients with NSLBP, due to MF-AMI induced depletion of spinal stabilization; considers current understandings and interventions for NSLBP, including the contributing role of MF-AMI; and details the reasons why slacklining could be considered as a potential adjuvant intervention for NSLBP through its indirect-involuntary action. This action is hypothesized to occur through an over-ride or inhibition of central down-regulatory induced muscle insufficiency, present due to AMI. This subsequently allows neuroplasticity, normal neuro-motor sequencing and muscle re-activation, which facilitates innate advantageous spinal stabilization. This in-turn addresses and reduces NSLBP, its concurrent symptoms and functional disability. This process is hypothesized to occur through four neuro-physiological processing pathways: finite neural delay; movement-control phenotypes; inhibition of action and the innate primordial imperative; and accentuated corticospinal drive. Further research is recommended to investigate these hypotheses and the effect of slacklining as an adjuvant therapy in cohort and control studies of NSLBP populations.

Slacklining: An explanatory multi-dimensional model considering classical mechanics, biopsychosocial health and time.

This paper aims to overcome slacklining's limited formulated explanatory models. Slacklining is an activity with increasing recreational use, but also has progressive adoption into prehabilitation and rehabilitation. Slacklining is achieved through self-learned strategies that optimize energy expenditure without conceding dynamic stability, during the neuromechanical action of balance retention on a tightened band. Evolved from rope-walking or 'Funambulus', slacklining has an extensive history, yet limited and only recent published research, particularly for clinical interventions and in-depth hypothesized multi-dimensional models describing the neuromechanical control strategies. These 'knowledge-gaps' can be overcome by providing an, explanatory model, that evolves and progresses existing standards, and explains the broader circumstances of slacklining's use. This model details the individual's capacity to employ control strategies that achieve stability, functional movement and progressive technical ability. The model considers contributing entities derived from: Self-learned control of movement patterns; subjected to classical mechanical forces governed by Newton's physical laws; influenced by biopsychosocial health factors; and within time's multi-faceted perspectives, including as a quantified unit and as a spatial and cortical experience. Consequently, specific patient and situational uses may be initiated within the framework of evidence based medicine that ensures a multi-tiered context of slacklining applications in movement, balance and stability. Further research is required to investigate and mathematically define this proposed model and potentially enable an improved understanding of human functional movement. This will include its application in other diverse constructed and mechanical applications in varied environments, automation levels, robotics, mechatronics and artificial-intelligence factors, including machine learning related to movement phenotypes and applications.

Cross-cultural adaptation, validity, and reliability of the Persian version of the Upper Limb Functional Index.

Introduction: The Upper Limb Functional Index (ULFI) is a patient-reported outcome measure (PROM) designed to evaluate both the functional status and the level of participation in patients with upper limb musculoskeletal disorders (ULMSDs). The purpose of this study was translation, cross-cultural adaptation, and psychometric evaluation of the original ULFI into Persian (ULFI-Pr). Methods: The original ULFI was translated into Persian through double forward and backward translations. Consecutive symptomatic upper limb patients (n = 180, male = 60%, age = 38.21 ± 7.13) were recruited and completed the ULFI-Pr and the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaires. Internal consistency and test-retest reliability were determined using Cronbach's Alpha and the Intra-class Correlation Coefficient (ICC2.1). Criterion validity was analyzed by evaluating the Pearson's r correlation coefficient between the ULFI-Pr and DASH questionnaires. Construct validity was examined through exploratory factor analysis (EFA) using Maximum Likelihood Extraction with Promax rotation. Results: The original ULFI was translated and cross-culturally adapted into Persian with only minor wording changes. The ULFI-Pr demonstrated high levels of internal consistency (α = 0.91) and test-retest reliability (ICC2.1=0.92). The correlation between the ULFI and DASH was high (r = 0.71). The EFA demonstrated a one-factor structure that explained 38.2% of total variance. No floor or ceiling effects were observed. Conclusion: The ULFI-Pr can be considered as a region-specific, single-factor structure PROM for evaluation of patients with upper limb disorders for clinical and research purposes in Persian language populations.

The Politics of Chronic LBP: Can We Rely on a Proxy-Vote? Linking Multifidus Intra-Myo-Cellular Lipid (IMCL) Fatty Infiltration With Arthrogenic Muscle Inhibition (AMI)-induced Chronic Nonspecific Low Back Pain.

STUDY DESIGN: Retrospective review of the literature. OBJECTIVE: To update recent trends in the use of magnetic resonance spectroscopy (MRS) analysis for CLBP. SUMMARY OF BACKGROUND DATA: The lumbar multifidus (MF) muscle has drawn sustained interest for some time, particularly related to its structure, role in spinal stability, and its association and clinical significance with CLBP. Additionally, the presence of MF-arthrogenic muscle inhibition (AMI) and its relation to induced CLBP, through depleted lumbar stabilization, has gained increased recognition. In contrast, the differential diagnostic use of MRS analysis has suggested specific links between the presence of MF myo-cellular lipid (MCL) infiltration and CLBP patients. METHODS: Review of the literature related to CLBP with the keywords MCL, MRS analysis, and MF-AMI. RESULTS: No articles discussed CLBP using the three key concepts in a single context. The use of MRS analysis has the capacity to distinguish between Extra-MCL (EMCL) and intra-MCL (IMCL) infiltration within the lumbar MF. It is suggested that EMCLs are more likely to be associated with age-related change, while the IMCLs appear more likely to be associated with the presence of CLBP. The increased recognition of MF-AMI as a primary cause of CLBP, and the potential that AMI parallels the presence of IMCLs, facilitates possible use of MRS as a means to quantify the basis of lumbar MF-AMI CLBP, and that proportional IMCL changes in the MF could serve as a 'proxy' to indicate the effectiveness of interventions directed at MF activation. CONCLUSIONS: It may be possible for IMCLs to serve as a 'proxy' prognostic marker of lumbar MF-AMI in CLBP patients. Further, if this assertion were correct, then reductions in IMCLs could potentially quantify recovery and the efficacy of rehabilitation management strategies directed at lumbar MF activation.Level of Evidence: 5.

Validity and reliability of the Persian version of the Quick Exposure Check (QEC) in Iranian construction workers.

BACKGROUND: The Quick Exposure Check (QEC) is an instrument to identify occupational risk factors, and to screen subjects for the risk of musculoskeletal disorders in their workplace. OBJECTIVES: The aim of this prospective observational study was the cross-cultural adaptation of the QEC for Persian (QEC-Pr) speaking workers and the determination of the minimally required psychometric properties, including reliability and validity, in a Persian population. METHODS: The forward-backward translation was completed according to the published guidelines. A total of 217 male construction workers were recruited. The Rapid Upper Limb Assessment (RULA) tool was used as the criterion. The Inter- and intra-rater reliability was performed respectively in a sub-sample of n = 50 and n = 30. Convergent validity was determined from the correlation between the QEC-Pr and the RULA. Internal consistency was assessed using Cronbach's α. RESULTS: High levels of inter-rater reliability (ICC2.1 range = 0.79-0.93), intra-rater reliability (ICC2.1 range = 0.74-0.89) and internal consistency (α= 0.74) were obtained. Concurrent validity between the different sections of the QEC and RULA scores were determined to be fair but below the desired level (range r = 0.41-0.44). CONCLUSIONS: The QEC-Pr can be applied as a specific risk assessment instrument for different occupational situations, such as the construction industry, in Persian language populations.