فهرست مطالب hamid reza mokhtarinia

Changes in mental workload are related to performance and level of fatigue, stress, human error, and job dissatisfaction. Questionnaires are simple, accessible, and valid tools for the assessment of mental workload. Therefore, the present study aimed at translation, cultural adaptation, and evaluation of psychometric properties of the Carmen-Q mental workload questionnaire.

This study was conducted on 296 subjects  (100 women and 196 men) with a mean age of 38.59±7.61 years, working in industrial and administrative sectors in several centers in Saveh. The process of translation and cultural adaptation was carried out in accordance with relevant guidelines and included the stages of forward and backward translation, synthesizing and preparing a final version, piloting, and then final approval of the Persian version. Psychometric properties, including face validity (simplicity and readability), content validity (through content validity index), convergent validity (through correlation with NASA-TLX questionnaire), and internal consistency (using Cronbach's alpha coefficient) were assessed.

The translation, cultural adaptation, and face validity assessment were carried out according to related guidelines, and the text underwent some minor changes. The Content Validity Index values for each of the items and its total (0.914) were acceptable. Cronbach's alpha value was acceptable for all items (0.91) and each subscale (above 0.8). Pearson's correlation coefficient displayed a moderate to good relationship between Carmen-Q and NASA task load index.

The Persian version of the Carmen-Q questionnaire is a valid and reliable tool for evaluating mental workload in Iranian society.

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.

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).

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.

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.

Objectives :

Due to the decline in the function of balance system in older adults and the importance of having an active old age, it is very important to maintain independence during daily living activities such as shopping, holding and carrying an external load. This study aims to determine the effect of external load magnitude and holding mode on the postural sway during standing in healthy community-dwelling older adults.

Methods & Materials:

 In this quasi-experimental study, 15 healthy community-dwelling older adults in Tehran, Iran (7 men and 8 women) with a mean age of 71.53±6.18 years who were independent in daily living activities such as shopping and carrying shopping bags were enrolled using a conveneince sampling method. The independent variables were holding manual loads with a magnitude of 0%, 5%, 10%, 15%, and 20 % of body weight in symmetrical (both hands) and asymmetrical (dominant or non-dominant hand) conditions, standing still on the force plate for 30 seconds. Dependent variables included the amount and velocity of the displacement of the center of pressure (COP) in two anteroposterior and mediolateral directions and the area of the COP displacement.

Results:

 The effect of holding manual loads symmetrically and asymmetrically and the manual load magnitude on the amount and velocity of COP displacement in anteroposterior direction was signifcant, while their interaction effect was not significant on any variables. The paired t-test results showed that the amount and velocity of COP displacement in anteroposterior direction at asymmetric condition was significantly different compared to the symmetrical condition, but there was no significant difference between holding with dominant and non-dominant hands. The amount of COP displacement in anteroposterior direction with 5%, 10%, 15% and 20% of body weight were higher and statistically significant compared to the load magnitude of 0% (P<0.05). The effects of load holding mode and load magnitude were not statistically significant on any of the COP variables in the mediolateral direction. 

Conclusion:

 Aging, Postural balance, External load Holding external loads asymmetrically with any magnitudes can increase the amount and velocity of COP displacement in the anteroposterior direction. For preventing falls, it is recommended for the elderly to pay attention to the fact that holding an external load with two hands is less challenging to the balance system than holding with one hand, whether dominant or non-dominant. In terms of the load magnitude, an external load with 5% of body weight can challenge the balance system compared to the situation without external load. With some exceptions, there is no difference between loads of 5%, 10%, 15% and 20% of body weight.

Work-related musculoskeletal disorders are multifactorial conditions that result in time loss, disability, and increased economical costs. The aim of the current study was to evaluate the role of the physical, environmental and psychosocial factors in the development of musculoskeletal disorders in workers in the production and assembly of auto parts in Qom city in 2021.
In this cross-sectional study, 211 participants through an inconvenience sampling method entered the study. The demographic characteristics of participants and the prevalence of musculoskeletal disorders were assessed by a self-report questionnaire and the Extended Nordic questionnaire, respectively. The mental workload was evaluated by the NASA-TLX index and the physical, environmental and psychosocial risk factors were evaluated by the Structured Multidisciplinary Work Evaluation Tool (SMET). The binary logistic regression method was used to show the role of the different risk factors in the development of MSDs.
Participants had an average age of 33.9 years (SD = 6.9). The lifetime prevalence of MSDs was obtained at about 77.72% in at least one area of the body. The neck, back, and shoulder areas were the most common regions. Gender, smoking history, surgery history, age, past surgery history, and sports history were most effective in the development of MSDs. In addition, subscales of mental workload play a role in causing pain in the shoulders, upper back, back and knees. SMET subscales play an effective role in the neck (OR = 1.396), upper back (OR = 1.663), hip, and knee, wrist/hand, and ankle/foot pain.
According to the role of various factors in developing disorders, the physical, psychosocial, and environmental factors should be considered simultaneously in planning preventive programs and ergonomics interventions.

Fugl-Meyer Assessment (FMA) is the common scale for clinical and functional evaluation of sensorimotor conditions and related Upper Extremity (UE) dysfunction after stroke. This study was done to translate and cross-culturally adjust the original upper extremity FMA (FMA-UE) into Persian and to evaluate the psychometric properties of the translated version. 

A procedure of forward/backward translation based on the published guidelines was adopted and two independent bilingual translators performed the translations in each stage. The conceptual and semantic equivalence was obtained through a consensus between experts. Consecutive stroke patients (n=47, male=63%) with a mean age of 61.54±10.9 years were recruited. Content, face, and concurrent validity was calculated using the content validity index, a cognitive interview, and correlation with the Wolf Motor Function Test (WMFT). Internal consistency and intra-rater reliability were determined by calculating Cronbach’s alpha and the Intra-Class Correlation coefficient (ICC2.1).

During the forward translation and cultural adjustment, some wording changes were performed. In the forward translation, the most challenging clarifications are related to anatomical terms and positions. The total FMA-Persian score demonstrated acceptable internal consistency (α=0.86) and intra-rater reliability (ICC2.1=0.96). Joint passive motion showed the lowest reliability among all domains. The FMA motor subscales showed a floor effect, while sensation, joint passive motion, and pain domains showed ceiling effects. The correlation between the FMA-UE score and the WMFT was 0.78 (P<0.001). 

The FMA-UE translation and adjustment were performed successfully into the Persian language. The results of the current study found FMA-UE as an acceptable, reliable, and valid instrument for evaluating the upper limb function after stroke in Persian-speaking patients. However, it should be noted that floor and ceiling effects are respectively present in the domains of the motor subscales and for sensation, passive motion, and pain.

instruments and methods evaluate addiction to the Internet, mobile, and smartphone use. Subject-reported outcome measures, such as the Smartphone Addiction Scale (SAS) assess such addiction. The objectives of this study were to cross-culturally adapt the SAS into Persian (SAS-Pr) and to evaluate the properties of reliability and validity in the Persian setting.

The English version of the SAS was translated into Persian according to the published guidelines, using forward-translation, synthesis, back translation, consolidated consensus translations from an expert committee, and in pilot-testing. The pilot trial was performed with recruited medical students (n=50) with an interview used to determine the comprehensibility, readability, understandability, interpretation, and cultural relevance of the questionnaire. A further sample of medical students (n=100) was recruited for test-retest reliability performed at baseline and 7-14 days later, using the intraclass correlation coefficient (ICC2,1) and internal consistency using Cronbach’s α.

The translation of SAS-Pr was achieved with minimum difficulty. During this process, item 15 was revised and in items 24 and 25, the “telegram” phrase was added. The participants found the comprehensibility, readability, understandability, interpretation, and completeness of the questionnaire conclusive. Furthermore, high levels of test-retest reliability (ICC2,1=0.81) and internal consistency (α=0.948) were obtained.

The SAS-Pr adaptation was successful and the translated version showed promising positive psychometric properties. The SAS-Pr can be applied in research settings and in identifying Persian-speaking people at risk of addiction to the smartphone.

Spinal load and muscle activity in occupation settings is an area of increasing concern. Regarding technological advancements, in diverse occupations the spinal loads have increased through constrained seated postures. Back belts are consequently used in prophylactic and conservative management of occupational low back pain (LBP) in two distinct settings, prevention in industry, and treatment in LBP management. Industrial sites utilize belts for LBPprophylaxis on a large scale with their design and user experience (UE) influencing both the effectiveness and the workers’ compliance. This pilot study aims at determining the effectiveness of the new Tehran Back Belt (TBB) and assesses both UE and biomechanical effect (BE) on paraspinal muscle activity in healthy subjects. A pretest-posttest study. Stage-1, design and fabrication of the TBB. Stage-2, the UE of the designed belt evaluated in healthy volunteers (n=30) via a checklist. The BE was determined from the level of lumbar extensor and trunk flexor muscle activity gauged during two test conditions of sitting posture (with and without belt) over 35-minute periods. Most subjects (>90%) reported high ‘ease of use’ and ‘comfort’ while wearing the TBB.The BE statistical analysis showed significantly reduced EMG activity levels for the longissimus(P = 0.012, η2=0.24), rectus abdominis (P=0.024, η2=0.18) and internal oblique (P=0.001,η2=0.44) muscles in belt-use conditions. Decreased muscle activity while using the TBB is potentially advantageous for workers as spinal muscle activity is significantly reduced. Further investigations for longer duration effects and during real work office-based activities are warranted.

Objective Work-related Musculoskeletal Disorders (MSDs) happen due to risk factors during work, across the world, especially in developing countries. Multiple risk factors (physical, psychosocial and mental) have contributed in MSDs as with most chronic diseases. Several tools are used to evaluate these risk factors. Quick Exposure Check (QEC) is one of the most accurate and quick-response tools for identifying these risk factors. The purpose of the present study is to translate cultural adaptation and to verify the reliability of the Persian-language rapid assessment evaluation checklist.
Materials & Methods This study is a methodological study. In this study, the intercultural equivalence of the QEC questionnaire was performed using the international quality of life assessment project. For doing face validity, the questionnaire was completed by 12 ergonomic experts and 15 employees. In this study, (ICC), (SEM), (α Cronbach) The checklist was reviewed on 80 construction workers. They were divided into two groups of 30 and 50. The questionnaire was completed at intervals of 3-7 days in two rounds.
Results The Persian version of QEC questionnaire was reported with easy terminology, wordage, and phrases. Interpreters were also unanimous about this, and the quality of translation was clearly translatable , the use of common language, conceptual equivalence, and the overall quality of translation was desirable. And the interpreter's agreement was satisfactory. In other words, the results of the formal validity check showed that all items were approved. High levels of internal consistency (α=0.74), inter-rater reliability (r=0.79-0.93) and intra-rater reliability (r=0.74-0.89) were obtained, too. Face validity had acceptable results from both workers and specialists’ perspective. In addition, SEM scale for inter-rater (4.9-0.4), intra-rater (2.8-0.73) showed low random errors.
Conclusion Questionnaire was verbally verified in a way that all 16 questions were clear, simple, and understandable with acceptable reliability. Therefore, The QEC can be applied as a specific risk assessment instrument for industrial and research studies in Persian language populations

Objective Kyphosis is one of the common abnormalities of the spine. However, correct preservation of the posture can play an important role in preventing and treating kyphosis. Biofeedback systems are among the methods used to prevent postural dysfunction. This study aimed to design a biofeedback tool to prevent kyphosis and evaluated reliability and validity of this tool.
Materials & Methods total of 17 students aged between 18 and 30 years participated in the study as inappropriately. In this study, a flexible ruler was used as a golden standard to measure the kyphosis. First, a microcontroller-based kyphosis control biofeedback device was designed using a flexural sensor. This device consists of a vibration generator that activates when microcontroller detects a kyphotic situation. In other words, by changing the physical condition, the flexural sensor resistance used in the smart biofeedback tool changes accordingly and the data collected by the flexural sensor are converted into a voltage variation with a simple resistance circuit. The output of the flexural sensor is input to the microcontroller so that as soon as the microcontroller detects an incorrect physical condition, it sends a control signal (based on the predefined threshold for the microcontroller) in a vibration feedback. If the curvature value is more than the threshold and lasts for at least 30 seconds, it will alert the user with vibration feedback. Vibration alert continues as long as the user is in the kyphotic situation and stops as soon as the user leaves the kyphotic situation and returns to the natural state. After installing the designed biofeedback tool on the target area of the body, the tool error is evaluated by counting the number of warnings in the normal state and lack of warning in the kyphotic condition. In addition, to check the repeatability of the biofeedback tool, measurements were made in two neutral conditions and a tissue for each situation twice, with a distance of 2 hours. In this research, the tool validity was measured by Kappa coefficient based on sensitivity, specificity, and reliability.
Results Correction of the physical condition is an effective technique used to reduce mechanical stress on the neck and shoulders by taking a natural state of the body. Wearable technology is a way to achieve this objective by continuously monitoring the physical condition of the person and giving him or her the needed feedback when the person’s physical condition deviates from normal condition. In this research, a wearable tool was designed that people can use it very easily. Therefore, it can be used as a useful, simple, and non-invasive tool for clinical evaluation and measurement of kyphotic postural information. With further development of data recordings and feedback mechanisms, this system can be transformed into a portable tracking and posturing system to educate patients with spine deviations. This system is an inexpensive user-friendly device.
The results showed that the sensitivity of the designed biofeedback tool was 17.64% and its property was 100%. The kappa index was calculated at 100% for both neutral states, but in the first one, 17.64% was measured in the first load and 12% in the second time. Regarding the repeatability of the biofeedback tool, the studies showed that the results of the first and second times did not differ significantly.
Conclusion To the results, the biofeedback tool has sufficient validity in the neutral state, but it was not sufficient in the paper situation . In other words, the designed biofeedback device does not correctly diagnose the physical condition of the body in accordance with the golden standard (flexible ruler). In this regard, further consideration should be given to address its deficiencies. In addition, Kappa index values showed that the biofeedback tool was not well-suited to the kyphotic condition. However, this tool has a great deal of reliability at the time.

Individuals performance at the workplace is affected by different adopted postures. Sitting postures are mostly used during office work. Improper sitting postures may cause muscle fatigue and discomfort in the spine and also result in mental workload. Poor posture may result in human errors and delay in information processing. Previous studies have demonstrated the relationship between static sitting postures and cognitive factors such as reaction time to an auditory stimulus. Also, some recent studies have demonstrated the effect of static postures on cognitive performance. To our knowledge, none of the studies had considered the sitting and standing postures effects on cognitive performance simultaneously. The aim of this study was to evaluate cognitive performance during three different static working postures: standard sitting, standing, and self-selected sitting postures.
This semi-experimental design study was conducted on the twenty-nine healthy students (aged 20-30 years). The non-probability sampling method was selected. All participants provided their written informed consent. Participants with no musculoskeletal disorders, heart disease, spine surgery, and history of depression and stress were selected. Their depression status and level of stress were measured using Beck questionnaire. The study was approved by the Ethics Committee of University of Social Welfare and Rehabilitation Sciences. Subjects performed complex Stroop test and typing activity in an office-like laboratory setting at the University of Social Welfare and Rehabilitation Sciences. Stroop test lasted about 9-12 minutes, and a typing task was also designed for approximately 5 minutes for all subjects. Three random postures were selected based on common postures used in the office. The effects of the postures (standard standing, standard sitting, and self-selected sitting posture) on dependent variables such as total test duration and reaction time to congruent and incongruent stimulus, number of typing words and number of typing error were assessed with Repeated Measures ANOVA. To examine the differences between groups, the paired t-test was used.
The results demonstrated that reaction time measure and number of typing error (accuracy) were affected by postures (P=0.001). Post hoc analysis demonstrated that reaction time was significantly different between self-selected sitting posture and standard sitting posture (P=0.001), self-selected sitting posture and standard standing posture (P=0.043), standard sitting posture and standard standing posture (P=0.001). With considering the average amount of reaction time to congruent and incongruent cases, it was observed that there is less reaction time in the standardized sitting posture (M=628.67 ms) compared to the self-selected sitting posture (M=689.41 ms) and standard standing posture (M= 675.16 ms). Also, among the three postures studied a significant difference was observed in the number of typing error words (P=0.001). The number of typing error (accuracy) was lower in this posture compared to the two other postures (M=1.58).
This study demonstrates that cognitive performance is affected by working postures. This study demonstrates that standard sitting posture is the best posture. Therefore, it is recommended that sitting posture can help in increasing cognitive performance in the workplace.

Educational environment is a major factor for teacher and student’s health, comfort and academic performance. Nowadays, technology improvement in classroom environment has exposed the users to ergonomics risk factors. The aim of this study was to assess the ergonomics of computer lab from student and expert’s point of view.
This analytic descriptive cross sectional study was conducted in the University of Social Welfare and Rehabilitation Sciences in 2016. Noise, lightening status, classroom environment and anthropometrics adjustment between students and class furniture dimensions were measured with sound level meter, luxmeter (Hagner EC1), Computer Classroom Environment Inventory (CCEI) checklist and anthropometric kit, respectively.
Results showed that space environment, work space and computer station were not satisfactory but visual space seemed appropriate which was consistent with student’s opinion. Subjective and objective evaluation of acoustical comfort was not desirable. There was not any match between student’s physical dimensions and furniture dimensions except the under table space which was consistent with the students opinions.
Ergonomics intervention in order to increase the ergonomics conditions of computer lab should be considered.

With the global growth of elderly population, their increasing need to public and recreational spaces has become a novel challenge. Such spaces should be designed based on ergonomic principles in order to decrease their risk of injury. This research aimed to design an ergonomic bench for the elderly people with respect to their anthropometric dimensions. In this descriptive study, 90 older participants, 24 females and 66 males, aged over 60 years, were recruited by cluster sampling method. A trained ergonomists measured their 13 anthropometric dimensions based on ISO (7250-1:2008). The dimensions of the available benches in the parks were also measured. Then, the fitness of elderly’s anthropometric parameters were compared with the dimensions of the benches (N=100) in the parks. We also explored the problems and difficulties of the using benches by “future workshop technique”. A total of 45 elder subjects were participated in the workshop (recruited by convenience sampling method). They were asked about their problems in using the benches. Their comments and suggestion were sorted and prioritized. Then, using CATIA software and considering the proposed solutions, a pilot ergonomic bench was designed in accordance with the elder anthropometric dimensions. The descriptive and inferential analyses were done by SPSS V. 16. Descriptive results of the anthropometrics dimensions of the older people including Mean, Standard Deviation (SD) as well as percentiles, frequency, cumulative frequency, percentage, Mean and SD for the dimensions of the benches were provided. The study results show a significant difference between the bench seating depth and elderly’s buttock-popliteal length, also between bench seating width and elderly’s buttock width, and finally between bench backrest height and elderly’s shoulder height. There was no significant difference between bench seating height of concrete benches and popliteal height dimension, as well as between elbow rest height of iron benches and arm support height. The elderly take undesirable postures during sitting on incompatible furniture (knee bending, trunk flexion, twisting, etc.).These unnatural postures impose physical strain on them. It is recommended that an anthropometric database of older adults be prepared so that new adjustable furniture can be designed based on these data.

Because walking is the main activity of humans for movement, many research studies have been conducted to understand its details. One of the main issues in this regard is gait symmetry and the effect of various factors on it. Accordingly, the present study aimed to review the selected factors affecting gait symmetry.
A literature review was performed on articles published from 2000 to 2016 using Science Direct, Google scholar, PubMed, Ovid Medline, Scopus and Medline databases. The search keywords were “gait asymmetry,” “bilateral coordination,” “bilateral asymmetry,” “limb dominance,” “laterality,” “limb preference” and “performance asymmetry.”
A total of 60 scientific articles were selected according to the research criteria by searching the relevant articles published from 2000 to 2016 in reliable scientific databases.
A review of the previous studies shows that walking in normal people is asymmetric in terms of the lower limb function. Also, limb disorder due to the illness and or disorder creates gait asymmetry. Therefore, regaining perfect symmetry or decreasing gait asymmetry by exercise and intervention in such individuals is considered a method to examine the success of rehabilitation process. However, as factors like movement speed and age can affect gait asymmetry, they should be controlled during the examination of gait asymmetry. Moreover, this information could be useful for gait assessment, clinical prescriptions for patients with abnormalities, designing orthosis and prosthesis, as well as improving the performance of athletes.

Due to the fact that walking is the main activity of humans to relocate, understanding its complexity and its different angles has long been the focus of various studies. One of the main issues in this regard is gait symmetry. Accordingly, the aim of the present study was investigating the concept of gait symmetry and the methods for evaluating it.
A search among the related articles published from 2000 to 2015 in valid scientific databases, according to the research criteria, resulted in 71 scientific articles selected for the present review study.
Review of the previous studies showed that generally, from kinematical and kinetical point of view, walking in participants with and without abnormalities was asymmetrical and this condition is represented in all measured kinematic and kinetic parameters except in a few studies. Also, the methods of evaluating gait symmetry could generally be categorized into symmetry indices and statistical methods. In this situation, symmetry indices, despite their ease of application, could not represent the spatial-time complexity of walking cycle because of single-variable evaluations. In addition, the main limitation of statistical methods is that they do not present a qualitative value. Thus, for neither of these two methods is normal data available.
With respect to the fact that during walking lower limbs have an asymmetrical behavior in normal/healthy individuals, which is due to their different functional tasks in control and propulsion, the assumption of gaining perfect symmetry after rehabilitation and intervention does not seems to be true. However, it is crucial to carry out further investigations in order to obtain the normal range of gait asymmetry in different participants and to understand fundamental factors affecting gait asymmetry.

Children’s interaction with the environment considerably influences their growth. To create an environment that guarantees growth and development of children’s skills, children’s characteristics should be considered in selecting facilities, design, and setting of child-related environments. Proper tools should be used to study the compliance of the current design of playrooms in preschool centers with the criteria of user-centered design. The research objective was to design a tool for ergonomic assessment of preschool playrooms with a cooperative approach.
In this descriptive-analytical research, after reviewing the resources and visiting the place, the preliminary items of the assessment tool were extracted. Afterwards, a 43-item assessment tool was developed through group sessions attended by experts and personnel of preschool centers. The validity of the tool was assessed through content and face validity assessment tests. Reliability of the test was measured by test-retest. The data were analyzed by Excel 2010 and SPSS15.
Research results indicated that 7 of the 43 items had low content validity and needed to be rejected. The calculated content validity index of the final version was 72.9, which was acceptable. During the content validity assessment, minor changes were made to two items. Results of the reliability also showed that this tool is repeatable with ICC=0.99
Considering the research results, the proposed assessment tool is properly efficient in assessing the environment of preschool centers.

Changes in horizontal velocity are known to influence many biomechanical characteristics of walking. The aim of the present study was to investigate the influence of movement velocity on lower-limb symmetry in normal walking.
A total of 11 angular and eight temporal parameters from sagittal plane angle-time curves of both lower limbs joints of 10 young able-bodied males were collected at each of the three relative velocity conditions (slow, normal and fast) using a six-camera motion capture system. Data was analyzed using a series of 2×3 repeated measures ANOVAs at the significance level of 0.05.
The results revealed that in all the four angular parameters and the six temporal parameters, on which speed and lower-limb had significant influence, asymmetry was found between the limbs in slow-velocity walking. However, in normal-velocity walking, the two angular parameters and the four temporal parameters and in fast-velocity walking only one of the temporal parameters demonstrated asymmetry between the limbs.
Analysis of interaction effects of walking velocity and lower-limb showed the greater asymmetries at the slow velocity condition with a trend toward improved symmetry at higher velocities. Considering the possibility of the effect of movement velocity, it is recommended that this factor be controlled during investigating the walking behavior in clinical and research settings.

The aim of this work was the translation, cultural adaptation and validation of the Persian version of the Rapid Office Stress Assessment (ROSA) checklist. Material & This methodological study was conducted according of IQOLA method. 100 office worker were selected in order to carry out a psychometric evaluation of the ROSA checklist by performing validity (face and convergent) analyses. The convergent validity was evaluated using RULA checklist. Upon major changes made to the ROSA checklist during the translation/cultural adaptation process, face validity of the Persian version was obtained. Spearman correlation coefficient between total score of ROSA check list and RULA checklist was significant (r=0.76, p The results indicated that the translated version of the ROSA checklist is acceptable in terms of face validity, convergent validity in target society, and hence provides a useful instrument for assessing Iranian office workers

Musculoskeletal disorders are the most common occupational injuries and constitute a huge global health problem with substantial economic and human cost as well as negative impact on the quality of life. The aim of this study was to determine the prevalence of musculoskeletal disorders and level of risk among the workers of the assembly line of a battery factory.
In this descriptive cross-sectional study performed in 2013, 138 workers aged between 20 and 46 years from assemble line of a battery construction company that have been selected randomly and filled out the NORDIC questionnaire.
Also, for the assessing physical posture during work, RULA method were applied and filled out by researcher. Statistical analyzing were done by SPSS (v.21).
On the basis of the findings of this study majority of the recruited population suffer from upper back 42 Workers(%30.4) and neck pain 36 workers (%26.1) and lower back pain 25 workers (%18.1) then by knee pain 16 workers (%11.6) respectively. Also results of RULA method analyzing showed that risk level score for 31.2, 53.1 and 15.6% of all postures were 4, 3 and 2 respectively.
The prevalence of MSDs in the workers was high. Most of postures are needed to be corrected because of high score in RULA method. Based on the obtained results, the most significant ergonomic problems in workers were found to be awkward postures, manual material handling and back bending and twisting.

Musculoskeletal disorders are among the top 10 injuries accounting for absence from work. The Extended Nordic Musculoskeletal Questionnaire (NMQ-E) is one of the many tools used to examine these disorders. The present study was conducted to translate and localize the NMQ-E and to evaluate the face validity and test-retest reliability of its Persian version. The present non-empirical methodological study used the International Quality Of Life Assessment (IQOLA) approach to translate the NMQ-E into Persian. The face validity of the Persian version was examined in a sample of 15 patients with musculoskeletal disorders (MSDs) and its absolute and relative test-retest reliability were examined in a sample of 48 patients using the Standard Error of Measurement (SEM) and the Intra-class Correlation Coefficient (ICC). The Kappa coefficient was also used to measure the inter-rater agreement for nominal variables. The translation and localization of the NMQ-E was deemed easy and acceptable. All the items of the questionnaire had an acceptable face validity. The Intra-class Correlation Coefficient and the Standard Error of Measurement of the Persian version of the NMQ-E were deemed acceptable (SEM=0.56-1.76 and ICC>0.7) and the Kappa coefficient was calculated as 0.78-1.00. The Persian version of the Extended Nordic Musculoskeletal Questionnaire showed an acceptable validity and test-retest reliability for assessing musculoskeletal disorders in Iranian patients.

Seniors’ population makes up a large portion of the world population and physical constraints faced by this group affect mental and social aspects of their life. Designing and creating new methods may be a solution through elderly mental and physical support to a more active attendance in the community. This article is a qualitative study based on user-centered approach which investigates seniors’ social activities and the related problems by concentration on their outdoor activities and its result suggesting a product for improving them. This study collected data through Distribution of the questionnaire, observation, and interview and documentation participants’ feedback. This qualitative study was conducted in four stages: In the first phase by distributing questionnaires among 42 patients 2: interviewing 19 seniors, 3: feedback and ideas documentation of 19 seniors, 4: Satisfaction survey as the final phase to check the suggested product. 12 women and 7 men participated in the last 3 phases and based on their ideas and also studying related and similar samples, data were collected and practical solutions were proposed. In the first phase the participants stated the shopping as their most significant outdoor activity and it was followed by exploring their favorite places for shopping which were the fruit and vegetable markets. Along with choosing the product related to the shopping process which was shopping bag by interviewing the problems were explored. Revealing the needs of elderly people in order to improve their social activities and designing a product for simplifying shopping daily goods, as their most important outdoor activity are the results of this study. An adjustable, safe and stagnate product by design can increase the satisfaction feeling by using the product and also reduce the dependence and need to the others. considering seniors’ problems thorough shopping, a solution in product design is proposed to facilitate them with some of the difficulties such as forgetfulness. For the future research considering the anthropometric measures to adjust the proposed solutions with the specific needs of users is foreseen. On the other hand studying the habits and behaviors which may cause damage to the elderly group while shopping and ease them by product design may increase the activities quality in a meaningful way.

The aim of the current study was to translate and cross-culturally adapt the Swedish Occupational Fatigue Inventory (SOFI) into Persian and to evaluate its face and convergent validity.Method & Material: A methodological study was performed according to standard IQOLA protocols, including the following steps: translating the SOFI questionnaire, evaluating the quality of the translation, back-translation and comparison of the English version with the Persian version by the original developer. The translated version was completed by 200 nurses. The Persian version of the Modified Fatigue Impact Scale (MFIS) questionnaire was used to evaluate the convergent validity. Spearman’s correlation was used to evaluate the correlation between the items. On the whole, the translations of the sentences were easy. The quality of the translation including the ‘clarity of translation, common language use, conceptual equivalence, and overall translation quality’ of the items was good. Face validity of the questionnaire was acceptable and did not lead to multiple changes in the questionnaire. Spearman’s correlation coefficient showed a high correlation between the total SOFI score and total (Persian) MFIS score (r=0.71 and p<0.01). The Persian version of the SOFI has acceptable face and convergent validity and is ready for further evaluation of its reliability.

It seems that the prevalence of Musculoskeletal Disorder (MSD) in laptop users is high although relatively few studies had focus in this group. The aim of this study was to investigate the prevalence of discomfort and pain in laptop user subjects and identifying the common adopted posture during usage of laptop. This descriptive cross sectional study was targeted at a group of 300 students aged between 20 and 30 who use laptop at work or at school in Tehran, Iran. A questionnaire was used for data gathering. Descriptive analytic methods were used to show prevalence rate of musculoskeletal pain. The results showed 77.3% of users reported at least one musculoskeletal complaint after using laptop. Among these neck trouble was the most prevalent MSD (60.3%), followed by wrist (27.3%) and right shoulder trouble (26%). Nearly 45% of subjects adopted kyphotic posture during laptop usage. The most common places where laptop was placed on were on the lap 28.7% and 24% on the office desk. On the base of Visual Analog scale the grade 4 was the most pain that was reported. The study has demonstrated that laptop usage causes musculoskeletal pains among students at work and in school and it is associated with the duration of use and adopted postures.

Stability is important to prevent falling during occupational and daily living activities. Control parameters such as direction of motion and external load can affect stability pattern. The purpose of this paper was to evaluate the effect of the mentioned control parameters on stability. Time series of lumbar rotation angle in 19 healthy subjects were investigated. Each subject performed spine flexionextension in two different directions of symmetric (sagittal plane) and asymmetric (between sagittal and transverse planes), with two loading cases of 8 Kg weight and load free. To evaluate dynamic stability of repetitive movement, a nonlinear method of largest Lyapunov exponent has been used. After calculating maximum Lyapunov exponent from each of the experimental cases, results of analysis of variance showed a significant difference between symmetric and asymmetric directions (p=0.016). To interpret this result we can suggest higher recruitment of the internal and external oblique muscle groups and higher mechanical constraints in spine during asymmetric tasks. Mean comparison showed that movement in symmetric direction has more instability than the asymmetric case. Moreover, presence of load and interaction between direction and load did not significantly affect local dynamic stability.

The purpose of this study was to identify the effects of external loads on balance control during upright stance in Chronic Low Back Pain (CLBP) patients and healthy adults. This study was a qausi-experimental design. External loads were applied to 23 young، healthy participants and 21 low back pain subjects، and effects on balance control were characterized by Center-of-Pressure (COP) based measures. Center COP data were used to calculate standard deviation of amplitude، standard deviation of velocity in anterior-posterior and medial-lateral directions، mean total velocity and phase plane parameters. We used two way ANOVA to explore the pre/post applying external load and the between groups difference. The results showed that applying external load had a significant main effect on the standard deviation of amplitude in anterior-posterior and medio-lateral direction and parameters. There was no interaction of load and group in this study. Also there was no difference between two groups at the beginning of the test. These data show that wearing 10 kg of external weight in a waistcoat increases the postural sway of subjects، which may in turn increase the likelihood of falls and injury.