Behavioral risk assessment of work-related musculoskeletal disorders among workers of petrochemical industries: protocol of a mixed method study

Abstract

Background

Musculoskeletal disorders (MSDs) are one of the most common occupational diseases and the main cause of disability worldwide. Work-related musculoskeletal disorders (WMSDs) are one of the common health risks and the most important cause of absenteeism due to disability in various industries, including the petrochemical industry, in developed and developing countries. These disorders have important social economic, and significant financial consequences due to direct and hidden costs. Health behaviors play a role in both creating and preventing musculoskeletal disorders in employees. Therefore, by identifying the influencing factors on these behaviors, it is possible to strengthen and improve the preventive behaviors of musculoskeletal disorders through educational intervention programs. This study aims to assess the behavioral risk of work-related musculoskeletal disorders, and design and implement an educational intervention to teach effective behaviors in the prevention of musculoskeletal disorders in petrochemical industry workers.

Methods

This study is a mixed-method study implemented in four stages involving the qualitative study, the design and evaluation of an instrument, the design of an experimental randomized clinical trial, and the psychometric evaluation of the instrument and the evaluation of the program. The research community consists of employees working in the petrochemical industry. The volume of samples in the qualitative study with the purposeful sampling method, in the instrument design stage based on the available sampling method, and also in the experimental study, the samples are employees suffering from work-related musculoskeletal disorders, who were selected based on a simple random method from among the employees of the petrochemical industry. Then they will be divided into intervention and control groups. The instruments of this research include a demographic questionnaire, a researcher-made questionnaire for measuring behavior, and two auxiliary instruments including the visual analog scale (VAS) and the Quebec Disability Scale. Evaluation is done in 4 stages: pre-test, immediately, 3, and 6 months after the intervention of both groups. The obtained data will be analyzed using SPSS software.

Discussion

Musculoskeletal disorders related (WMSDs) to work can harm employees’ health in various industries, including the petrochemical industry. This study attempts to evaluate the behavioral risk of work-related musculoskeletal disorders among petrochemical industry workers and design and implement an appropriate educational intervention program.

Trial registration

Iranian Registry of Clinical Trial (IRCT20240321061346N1). Registered on 2024–04-10.

Ethics Status: Ethics code: IR.MODARES.REC.1402.251.

Background

Despite the technological advances and the decrease in the amount of manpower in various industries [1], the prevalence of musculoskeletal disorders related to work (WMSDs) is still one of the biggest health problems in the working population in developed and developing countries, which has the highest number of different complaints among the working population [2, 3]. Carrying out work tasks in inappropriate physical, psychological, and ergonomic conditions constantly puts working people under muscle tension and vibration, which can lead to WMSDs [4]. These disorders can cause pain or damage to the body’s musculoskeletal system, including bones, tendons, nerves, ligaments, joints, cartilage, blood vessels, and intervertebral discs of the spine [1, 5].

WMSDs have a significant impact on social functions and health status, which leads to the inability to perform daily activities and as a result, reduces the quality of life and imposes health costs on individuals, organizations, and governments [4, 6]. The social and economic consequences of these disorders include reduced productivity due to absenteeism, leave and early retirement, loss of working days, significant financial consequences due to direct and hidden costs, and destructive effects on the quality of life, health, and job satisfaction. Individuals, organizations, and communities have been confirmed by numerous studies [6–9].

Statistics show that MSDs are the second most common occupational disease among 160 million occupational disorders in the world [10]. These disorders account for 7% of society’s diseases and 19% of hospitalizations [11, 12]. The prevalence of musculoskeletal disorders among workers has been reported to vary between 40 and 90% worldwide [13]. At the global level, musculoskeletal disorders are considered one of the main causes of health complaints among workers in various industries and the second cause of physical disability in developed countries [14, 15]. The prevalence of these disorders varies in different occupations. Global statistics show that the prevalence of WMSDs among petrochemical workers is about 41.5% [16].

In developing countries, insufficient understanding of occupational hazards by workers, lack of control measures on occupational hazards, and poorly designed workstations increase the burden of these disorders among workers [17]. In the petrochemical industry where products are continuously produced, employees are exposed to various musculoskeletal disorders risk factors such as long hours of sitting activity with high mental workload among control room employees, highly dynamic repetitive activities in repair and maintenance operations, turning valves Large, operating other large production line machinery, placing, holding or moving objects, frequent use of instruments, frequent rotation of valves, applying force and pressure on the hard surface [11, 18, 19].

Various studies show that MSDs are multifactorial. Physical factors are as follows: doing heavy, static, or monotonous work, intense or restricted posture, repetitive movements, ergonomics of the work environment, improper equipment, forces, exposure to vibration, manual handling of materials, excessive energy consumption, poor posture, bending excess, and rotation of the spine [4, 20, 21]. Psychosocial factors are as follows: organizational, financial, and social aspects, interpersonal relationships, work-rest cycle, rotational shift, unfavorable training, support of colleagues, and job dissatisfaction [22]. Demographic and individual factors are as follows: age, gender, body mass index, work experience, general health, sports activity, individual lifestyle, individual behavioral habits, individual psychological characteristics, and capacities [20], as risk factors in causing disorders musculoskeletal injuries caused by work play a role in employees of various industries, including the petrochemical industry [21].

According to the conducted studies, most of the reasons stated regarding MSDs are rooted in the causes of unhealthy and risky behavior performed by petrochemical industry employees [22, 23]. The reduction of these disorders will be possible if the workers of the petrochemical industry can observe and maintain the correct behaviors during their daily activities [24].

Based on the studies, it seems that the main obstacles in performing preventive behaviors of MSDs in the petrochemical industry are the lack of local and appropriate training for workers during work, the lack of ergonomic equipment suitable for the anthropometry of workers at work, the lack of cycle work is the right break in the workplace and health care costs [25, 26].

Health education is the most important principle in changing people’s behavior and health education planners can change people’s knowledge, attitudes, and beliefs by giving correct information and awareness [27]. With comprehensive reviews and evaluations of social, epidemiological, behavioral, individual, environmental, ecological, and educational dimensions and a detailed review of supporting and inhibiting policies in the work environment regarding existing health problems, planning, designing, and implementing suitable educational interventions, and providing practical suggestions and local will discuss various topics including the preventive behaviors of musculoskeletal disorders to eliminate and correct undesirable health behaviors and create, maintain and promote desirable behaviors in employees of various industries, including petrochemical industry workers [24, 28], and lead them to make decisions in the direction of adopting and carrying out good behavior [29].

Several studies show that health education and health promotion interventions include interventions with an emphasis on ergonomic principles and control measures in various productive work environments, including training workshops and re-designing workstations [2, 11, 30, 31], improving the condition of workstations, providing collaborative training programs (discussion and problem-solving practice) [8, 32], implementing participatory ergonomic intervention programs from passive training techniques (such as lectures, presentation of training videos, and preparation of pamphlets) to performance-based techniques (such as workstation redesign by encouraging workers to participate in the process of identifying risk factors) [2, 26, 30], implementing interventions by maintaining a balance between work and sufficient rest time during work and using stress reduction techniques [33, 34], appropriate design of work environments according to the characteristics of working people and based on the type of their work [35], and can play an important role in preventing and reducing MSDs among workers in various industries, including petrochemicals.

Several questionnaires such as the Nordic Musculoskeletal Disorders Questionnaire (NMDQ) [36], McGill Pain Questionnaire (MPQ) [37], Chronic Pain Rating Scale (CPGS) [38], and Rowland-Morris Disability Questionnaire [37] are used to understand how MSDs affect a person’s ability to perform normal activities.

However, these questionnaires cannot evaluate the causes and obstacles of performing or not performing preventive behaviors of MSDs. Therefore, to develop any intervention for the prevention of MSDs caused by work in different jobs, especially petrochemical industry employees, we will need a behavior measurement instrument so that we can understand the related causes and make appropriate interventions accordingly.

Objective

Therefore, according to the elimination of these limitations, the purpose of this multi-step and structured protocol is to identify behavioral risk factors that cause WMSDs, develop a tool, and design and implement an educational intervention to teach effective behaviors in the prevention of MSDs in petrochemical industry employees. To achieve the overall goal, the following four stages will be implemented.

Stage 1: Conducting a qualitative study with conventional content analysis method.

Stage 2: Design and validation of an instrument for measuring preventive behaviors of MSDs based on content analysis.

Stage 3: Designing and compiling the educational program (experimental randomized clinical trial).

Stage 4: Implementation and evaluation of the educational program and measurement of the stability of the program and psychometrics of the instrument.

Trial methods/design

The design of this protocol is a mixed-method study of the type of qualitative study and a randomized experimental clinical trial with a control group, which will be done in four stages. Its final goal is to design, validate, and evaluate an instrument for measuring preventive behaviors of MSDs of petrochemical industry employees. This protocol was developed and reported according to the recommendations of the Standard Protocol Items Recommendations for Interventional Trials (SPIRIT) [39] and will be conducted and reported following the Consolidated Standards of Reporting Trials (CONSORT) (Figs. 1, 2, and 3). Participant timeline and the steps to reach the final goal of this protocol are shown in Tables 1 and 2.

Fig. 1.

Study design of development and validation of questionnaire

Fig. 2.

First phase of the second stage of the study

Fig. 3.

Consort flow diagram

Table 1.

Schedule of enrolment, multidisciplinary intervention, and assessment of the intervention following the Standard Protocol Items Recommended for Clinical Trials (SPIRIT) guideline

Table 2.

The study overview

Stages	Aim	Methods	Participants
Stage 1: Qualitative study:
	Obtain the experiences of employees suffering from musculoskeletal disorders, to discover their needs, the history of musculoskeletal disorders in employees, to determine the behavioral and non-behavioral causes of musculoskeletal disorders in petrochemical industry employees. The cause is doing or not doing behaviors that lead to the creation or reduction of musculoskeletal disorders	In-depth interviews	Employees of the petrochemical industry
Stage 2: Designing, validating, and evaluating a questionnaire:
	Phase 1: Design of an initial questionnaire	Based on step 1	Researcher
	Phase 2: Psychometrics questionnaire	Content validity, face validity, construct validity (factor analysis), and questionnaire reliability. Preparation of the final questionnaire	Panel of experts, employees of the petrochemical industry
Stage 3: Design an educational intervention program (experimental randomized clinical trial):
	Preparing and designing an educational intervention program for the intervention group	Based on stage 1 and stage 2	Researcher
Stage 4: Implementation and evaluation of the educational intervention program:
	Phase1: Training the intervention group and transferring educational content to the intervention group	Based on face-to-face training	Researcher
	Phase2: Evaluating the educational intervention program and identifying the impact of the intervention in the intervention group	Questionnaire checklist	Employees of the petrochemical industry

The first stage of the study: the qualitative study of conventional content analysis (Fig. 1)

Qualitative studies are the best type of study to obtain behaviors, feelings, attitudes, characteristics, values, meanings, and perceptions that determine the health status and lifestyles of certain individuals or groups [40]. When the purpose of a study is to describe a phenomenon or when the theory or research literature on the phenomenon under study is limited, a qualitative study with conventional content analysis will be used.

The purpose of this stage

The purpose of this stage is to obtain the experiences of employees suffering from MSDs, discover their needs and experiences, determine the history of MSDs in employees, and determine the behavioral and non-behavioral causes of MSDs, the cause is doing or not doing behaviors that lead to the creation or reduction of musculoskeletal disorders in petrochemical industry employees.

Characteristics of the research community and participants in the qualitative study

At this stage, based on the available studies [41, 42], the researcher will conduct in-depth interviews with people who are a rich source of information (employees and managerial and executive agents of the petrochemical industry) willing to participate.

Sample size

In this stage of the research, the primary participants with maximum diversity in terms of (age, gender, education level, socio-economic level, work experience, cultural level, variety of job duties, and full-time, part-time, and contract workers) are selected using purposive sampling, which is a suitable method for qualitative research [41]. The sample size is based on the available studies [29, 42]. There will be 25 to 30 people, and the interview will continue until reaching information saturation and will continue until the participants do not add new data to the previous data and in this case, the sampling will stop [43].

Place and community of research at this stage

This study will be carried out in the Petrochemical Company of Asalouye City which is located in the south of Iran. The researcher will try to choose samples with maximum diversity (in terms of age, gender, socio-economic status, level of education, job level place of residence, etc.). Therefore, based on the criteria for entering the research, the participants will gradually enter the research and an individual and face-to-face interview will be conducted, this process will continue until the data reaches saturation and no new code is extracted.

Entry criteria for the qualitative study

Entry criteria for the qualitative study are as follows: being of Iranian origin, having a medical diagnosis of MSDs caused by work for at least 6 months (the patient to have passed the crisis period and be able to express his experiences in this field to the researcher), work experience of more than 2 years, age more than 18 years (age less than 18 years is adolescence and usually has its conditions), and able to express experiences and interested in participating in research.

Qualitative study data collection method

The data collection method in this stage of the research will be an unstructured interview. At this stage of the research, the researcher will be present in the petrochemical industry (with maximum environmental diversity from different centers of the industry) and after introducing himself and explaining the importance and objectives of the research and ensuring the confidentiality of the information and gaining the trust of the participants, he received a written informed consent signed by them. Will coordinate the time and place of the interview with them.

The interviews will be recorded by the researcher. The interview will be conducted individually and in a private and quiet place approved by the participants. At first, open questions will be used at the beginning of the interview to make it possible for the participants to fully describe their experiences regarding the phenomenon in question. Then, in the continuation of the interview process, the questions will be directed toward specialized questions and in line with the goals. After the participant’s answer, probing questions will be asked according to the answers.

The duration of the interviews will depend on the tolerance of the participants, the amount of information, and their willingness and agreement. Interviews continue until data saturation is reached. All recorded interviews will be typed in Word software.

Then the content analysis of the qualitative data is done based on the stage of analyzing the qualitative data obtained from the contracted qualitative study based on the steps proposed by Granheim and Lundman [41].

In the first stage of the research, the concepts related to the behavioral and non-behavioral causes of musculoskeletal disorders in petrochemical industry workers will be carefully defined. Then, based on the characteristics, similarities, and differences, they will be placed in different classes. Finally, the dimensions and areas that make up the concept of MSDs in petrochemical workers and questionnaire structures are determined.

Analysis of the data from the qualitative study

Then the information from the in-depth interviews will be analyzed by the researcher based on the Graneheim and Landman algorithm (a simple algorithm for classifying qualitative data) in qualitative content analysis in the following order [42].

At first, the entire recorded file of the interview will be written in Farsi. Second, the entire interview text will be considered as a unit of analysis. Third, semantic units will be extracted and the coding process will be done. The coding process and the extracted codes will be reviewed and approved by the experts of the research team. Fourth, similar codes will be placed under the main floors and floors. Fifth, finally emerging categories will be formed [44].

In this study, validity, confirmability, transferability, and reliability criteria will be used to evaluate the accuracy of the obtained results [43, 45].

Validity: with supporting evidence, the researcher ensures that the findings represent what is being studied [46].

Confirmability: the researcher ensures that the extracted findings are based on the participant’s answers and not the researcher’s interpretation and bias [46].

Transferability: with contextual information, the researcher confirms whether the results can be used in similar situations or not [46, 47].

Reliability: the researcher describes the study in detail so that the work can be repeated [45].

The second stage of the study: designing, validating, and evaluating an instrument for measuring preventive behaviors of musculoskeletal disorders based on content analysis (Fig. 1)

Objectives of instrument design and psychometrics

1. The practical definition of the concept of preventive behaviors of MSDs with the conventional qualitative content analysis method

2. Determining the objectives of the instrument for measuring preventive behaviors of MSDs

3. Compilation of the blueprint and design of the primary items of the instrument for measuring preventive behaviors of MSDs

4. Validation, quantitative evaluation, and psychometrics of the instrument for measuring preventive behaviors of MSDs

The second stage of the study consists of two phases. The first phase is instrument design and the second phase is instrument validation.

The first phase: instrument design including (Fig. 2)

• aExplanation of the conceptual model

To generate appropriate items, we need a theoretical basis that can show the necessary content areas for a new instrument. In this study, the operational definitions obtained from the conventional content analysis in the qualitative stage are the basis for the extraction of items and the purpose of the instrument.

• bDetermining research objectives

In this study, the goals of the instrument will be determined based on the dimensions and areas of the qualitative concept.

• iii.Roadmap design

To determine the necessary items for each structure, we need measurable variables from a qualitative study.

• iv.Instrument development (extracting and compiling items)

To convert the concepts resulting from the qualitative content analysis into appropriate items, first, the theoretical definitions of each dimension are defined based on the qualitative stage, and then the practical definition of each dimension is compiled by the objective and measurable characteristics of the same dimension [44].

Based on the aim of the research “design and validation of an instrument for measuring preventive behaviors of MSDs,” after extracting the final themes, the initial items of the questionnaire are extracted from the initial codes.

It consists of the total items obtained from the contractual content analysis of the pool of items [48]. Then the members of the research team will review the pool of items and select the best item. Similar items are removed and integrated, and thus questionnaire structures (appropriate items) are designed and evaluated.

The second phase: instrument validation

This stage of the study will be methodological research and in it, we will determine the validity and reliability of the instrument for measuring the preventive behaviors of MSDs.

Validity

In this study, content validity, face validity, and construct validity (factor analysis) are used to determine the validity of the instrument for measuring preventive behaviors of MSDs in petrochemical industry workers.

Content validity

According to Grant and Davis [49], content validity will be measured qualitatively and quantitatively. In the validity of qualitative content from the point of view of the panel of experts (health education, physiotherapy, occupational health, ergonomics, and safety), it will be used for grammatical points, proper use of words, correct place of phrases, scoring, transparency and simplicity of the items [42, 45].

In quantitative content validity, content validity ratio (C.V.R) and content validity index (C.V.I) will be used. For the content validity ratio, 10 experts (health education, physiotherapy, occupational health, ergonomics, and safety) are asked to comment on the necessity of the questionnaire items based on the three-part spectrum “necessary, useful but not necessary, not necessary.” Then the content validity ratio will be calculated. According to Lawshe et al. [50], scores above 0.62 are considered appropriate.

To calculate the content validity index, the evaluators check the degree of relevance of each item with the desired structure with four statements “not relevant, relatively relevant, relevant, and completely relevant” and then the score of the content validity index will be calculated for each item. Scores higher than 0.79 are considered appropriate, and scores between 0.7 and 0.8 will need to be revised and corrected [51, 52].

Face validity

The face validity of the instrument will be evaluated quantitatively and qualitatively.

In qualitative formal validity, 10 participants in the research are asked to comment on (the level of difficulty, comprehensibility, and ambiguity of each item), and after summarizing and analyzing, necessary changes are applied.

In quantitative formal validity, the participants are also asked to (specify the importance of each item based on a Likert scale of 1 to 5), and then the impact score of each item is calculated. Items with an impact factor greater than 1.5 are appropriate and items with a lower impact factor are removed (Formula 1) [44, 53].

$$\mathrm{Impact}\mathrm{Score}=\mathrm{Frequency}\times \mathrm{Importance}$$

Construct validity (factor analysis)

For the construct validity of the factor analysis method, which includes 4 basic steps, including the preparation of the correlation matrix of all the variables used in the analysis, estimation of commonality, extraction of factors, selection and rotation of factors to simplify and make the factor structure more understandable and interpret the results [41] will be used.

Exploratory factor analysis will be used to identify relationships between items and their relationship with the main variable under investigation, i.e., musculoskeletal disorders in petrochemical industry workers and instrument structures.

Kaiser–Meyer–Olkin (KMO) test and Bartlett’s sphericity test will be used to check sampling adequacy. After calculating the correlation matrix between the variables, the factors will be extracted and the variables that have a high correlation will be placed in a category or factor [41, 54].

According to McCallum and colleagues, the required sample size for factor analysis to determine the construct validity of the instrument is considered to be at least five times the number of instrument items [55].

Study environment: The study environment will be the Petrochemical Company of Asalouye City.

Study population: employees of Petrochemical Company of Asalouye city.

Sample size: The study sample will be selected based on the available sampling method from the research community.

The criteria for entering the samples into the study

1. Be of Iranian origin.

2. Willingness to participate in the study.

Data collection method

After obtaining the necessary permits from Tarbiat Modares University, the researcher will collect data with demographic questionnaires and measurement instruments. After his introduction, the researcher will mention the objectives of the study, the voluntary nature of participation in the study, the confidentiality of identity information, and the right to withdraw from participation in the study. After receiving the informed consent from the participants, the questionnaires will be provided to the participants to complete.

Reliability

The concept of the reliability of an instrument is that if we use the instrument again under completely similar conditions to measure the characteristic to be measured, how similar and reliable the results will be [56]. To check the reliability of the researcher-made questionnaire in this study, two retest methods will be used to measure external reliability and Cronbach’s alpha to measure internal reliability.

External reliability measurement

To measure external reliability, the test-re-test method (test questions are given twice to a single group under the same conditions) and the scores are compared. To find the correlation between scores, the Spearman or Pearson correlation coefficient is calculated. If the correlation value is 0.74 or more, it can be said that the instrument has a reliable feature [57].

Cronbach’s alpha

The internal reliability of the instrument is calculated through the coefficient of internal consistency (Cronbach’s alpha), which varies between 0 and 1. According to Bland and Altman’s theory, scales whose internal consistency coefficient is greater than 0.7 can be used in research [55, 58, 59].

Scoring

After obtaining the items and coordinating them with each other, the scoring rules will be selected in a 5-mode Likert spectrum. Formula 2 will be used to standardize the scoring based on the linear transformation standard of 100 [60]. Finally, a score between 0 and 100 is obtained.

$$\%\mathrm{Score}\frac{\mathrm{Minimum}\mathrm{possible}\mathrm{raw}{\mathrm{score}}_{\mathrm{o}}\mathrm{btained}\mathrm{raw}\mathrm{score}.}{\mathrm{Maximum}{\mathrm{score}}_{\mathrm{M}}\mathrm{inimum}\mathrm{score}}$$

Data analysis

SPSS version 22 statistical software will be used to analyze descriptive statistics and exploratory factor analysis to evaluate the validity of the constructs of the tool for measuring preventive behaviors of MSDs in petrochemical industry workers. The Kaiser–Meyer–Olkin (KMO) Index for sampling adequacy and Bartlett’s test of sphericity test if there is a redundancy between variables that can be summarized with some factors [61]. The factorial structure of the questionnaire will be extracted using Varimax rotation [62]. Internal consistency (Cronbach’s alpha), and stability will be examined by estimating the intraclass correlation coefficient (ICC) [63].

The third stage of the study: designing and compiling the educational program (experimental randomized clinical trial)

At first, after the initial needs assessments, based on the needs of the studied society, the existing situation, the review of reliable scientific sources, the laws, and the educational environment governing the national petrochemical industries, we will design an educational intervention program.

The educational content includes factors that determine the harmful behaviors of individuals, behavioral, environmental, ergonomic, managerial, organizational, redesigning workstations, etc. (based on the results of a qualitative study) that will be taught.

The educational content is pre-tested to adapt it to the target group. Therefore, the educational intervention program, the number of sessions, the duration of the sessions, and the number and duration of the reminder sessions are designed after collecting the initial information.

Objectives of intervention program design

1. Evaluation of behavior score (stretching/strength) preventing MSDs

2. Assessment of posture score during work and activity

3. Evaluation of pain score caused by MSDs

4. Assessment of disability score due to pain

In both intervention and control groups, before, immediately, 3 months, and 6 months after the intervention.

The fourth stage of the study: implementation and evaluation of the educational intervention program and evaluation of the sustainability of the program (Fig. 3).

Educational interventions

At this stage, the participants will be divided into two intervention and control groups based on the simple randomization sampling method. The intervention group will receive the educational intervention program and the control group will not receive any educational intervention program. The educational intervention will be designed to address specific hazards associated with MSDs in petrochemical workers. The content of the interventions includes the understanding of musculoskeletal disorders (information about common types of MSDs, causes, initial symptoms of pressure or damage, and their long-term consequences), principles of ergonomics (training of ergonomic practices appropriate to specific job tasks in the petrochemical industry), use of tools and equipment (instructions on proper use of tools and equipment to minimize strain), stress management (techniques for stress management that can help with muscle tension, such as mindfulness exercises, breathing techniques, and breaks to promote mental well-being), preventive behaviors MSDs (stretching and corrective movements to strengthen muscles and increase flexibility). These materials will be prepared and compiled through the needs assessment of the target group and the areas obtained from the WMSD preventive behavior measurement tool and using the opinions of experts in education and health promotion, occupational health, ergonomics, physiotherapy, and authentic scientific texts.

Presentation methods

These contents will be conducted including face-to-face education sessions(by a qualified ergonomist or occupational health professional, allowing for hands-on demonstrations and direct interaction), online methods ( e-learning platforms that workers can access at their convenience including videos, interactive quizzes, and downloadable resources, accommodating various learning styles), Practical sessions in the workplace setting (ergonomic assessments), poster presentations, pamphlets, infographics, short health messages, podcasts, animations, by the main researcher under the supervision of the research team.

Session frequency

Initial intensive training: holding workshops in the first few weeks (weekly sessions for a month).

Monthly refresher courses: reminder courses to adhere to the intervention and continue the behavior and retraining on specific topics, practical applications, and ergonomics.

Quarterly evaluations: Quarterly follow-ups to assess progress and check the performance of learned behaviors.

Duration of sessions

• The duration of each workshop will be 1.5 to 2 h, including interactive activities with comprehensive coverage of topics.

• Online sessions will be between 15 and 20 min to facilitate learning.

• Practical ergonomic assessments will last approximately 1 h to ensure sufficient time for feedback.

Sampling method

Based on the simple randomization sampling method, the participants in the study will be divided into two intervention and control groups. Based on this, first, the names of the participants will be marked with a code, and then they will be divided into two groups (intervention and control) by matching the codes. (All these works will be done by the main researcher.)

Sample size

Based on similar studies [3, 63–68], the sample size with 95% confidence and 80% test power, 53 people in the intervention group and 53 people in the control group, and considering 10% attrition for each group, 58 people in the intervention group and 58 people will be selected in the control group (in total, the total number of participants in the study is 116 people).

Study community: The studied society is the employees of petrochemical industries.

Study environment: The study environment is the Petrochemical Company of Asalouye City.

Study examples: Employees suffering from WMSDs.

Inclusion criteria

• Employees who are willing to participate in the study.

• Employees who have access to the Internet and the ability to use mobile phones.

• Employees who have more than two years of work experience in the petrochemical industry.

Exclusion criteria

• Having a second job

• Having any musculoskeletal disorders with a pathological cause.

• Having any diseases or problems that prevent a person from participating in studying and doing sports exercises.

Data collection instruments

In this study, the data collection instrument is a demographic questionnaire, a researcher-made questionnaire for measuring preventive behaviors of MSDs, and two auxiliary instruments, including the visual analog scale (VAS) [69], and The Quebec Back Pain Disability Scale [70]. Also, to validate the data reported by employees and reduce possible biases, we will use an ergonomic expert for objective ergonomic evaluation (such as recording the movement of employees during work) and ergonomic evaluation tools.

Data analysis

In this stage of the study, the data collected from the four stages of the pre-test, immediately, 3 months, and 6 months after the intervention will be coded and analyzed with SPSS software.

Kolmogorov–Smirnov test is used to check the normality of data distribution. If the data obtained from the research has a normal distribution, central indices, dispersion, and parametric statistical tests will be used, otherwise non-parametric statistical tests will be used.

Statistical tests of squares will be used to check the relationship between nominal variables. If the data is normal, the paired T-test will be used to compare and check the variables before and after the implementation of the educational intervention in a group, and if the data is not normally distributed, the Wilcoxon test will be used.

Repeated measurement tests will be used to compare variables several times and in several groups. Statistical tests of analysis of variance will be used to determine the effect of educational interventions on the employees participating in the research. To control the effect of confounding variables, the statistical method of co-variance analysis will be used.

Public participation

In this study, the general participation of the participants will be used to design, validate, and evaluate the instrument for measuring the preventive behaviors of MSDs and to design and evaluate the educational intervention program and its effect on the preventive behaviors of MSDs.

Effective control of confounding variables

To control the confounding variables such as (age, gender, income level, socio-economic level, lifestyle, type of job, and time variables) in this study, the researcher will use several methods.

• Assigning participants randomly to different groups

• Matching participants based on key confounding variables (eg, age, gender) to create comparable groups

• Using statistical techniques such as regression analysis to include confounding variables as covariates

• Using standardization criteria or using equal criteria to minimize variation caused by confounding factors.

Discussion

One of the features of this study is to pay attention to health promotion in industrial workplaces. This study will investigate the effect of educational intervention programs in creating preventive behaviors of MSDs in petrochemical industry workers.

The strengths of this study include conducting unstructured in-depth interviews, the mixed-method design, conducting qualitative research, focusing on behavioral risks, and development of a novel measurement instrument, psychometrics of the questionnaire, designing an educational intervention program based on the needs of the target group, and implement and evaluate the educational intervention program, in-person and face-to-face education, The easy access of the participants pointed to the researcher and experts of the research team.

The limitation of the current research is the self-reporting of the participants in completing the questionnaires, which the researcher and the experts of the research team used to solve this limitation and reduce potential bias, from objective ergonomic evaluations, three-dimensional motion recording systems to analyze situations, movements and performance of workers during work, standardized tools such as Rapid Upper Limb Assessment (RULA) [71], Rapid Whole Body Assessment (REBA) [72], field visits, and observations will be used.

Ethics and dissemination

1. Obtaining a license from the Faculty of Medical Sciences of Tarbiat Modares University with ID code (IR.MODARES.REC.1402.251)

2. Registration in Iran Clinical Trial Center with ID code (IRCT20240321061346N1). Registered on 2024–04-10

3. Obtaining a letter of introduction from Tarbiat Modares University for the petrochemical industry of Asalouye city

4. Obtaining informed consent from the participants in the study by the researcher

5. No need to write first and last names on the questionnaires

6. Assuring participants that their information is confidential

7. Providing educational content to the control group after the end of the research

Dissemination policy

The publishing of project findings in international journals is welcome. The authors would like to present the program results to the petrochemical workers and other stakeholders in Iran.

Ancillary and post-trial care

An ergonomist cooperates with the researchers to do the ancillary and post-trial care in this duty.

Ethics permission

The Ethics Committee for Health Research of Tarbiat Modares University approved the ethical principles with the following code: IR.MODARES.REC.1402.251. An informed consent form will be obtained from all participants. The data (when ready) will be available from the corresponding author on request.

Abbreviations

ZM

Zohreh Moradi

SST

Sedigheh Sadat Tavafian

FA

Fazlollah Ahmadi

OA

Omran Ahmadi

MSDs

Musculoskeletal disorders

WMSDs

Work-related musculoskeletal disorders

CONSORT

Consolidated Standards of Reporting Trials

SPIRIT

Standard Protocol Items Recommended for Clinical Trials

RULA

Rapid Upper Limb Assessment

REBA

Rapid  Entire Body Assessment

Authors’ contributions

ZM was the main investigator who collected and analyzed the data and wrote the first draft of the manuscript. SST supervised the study and contributed to the writing process. FA and OA were the study advisors who contributed to the analysis and interpretation and provided the final draft. All authors read and approved the final manuscript.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Data availability

The data will be available from the corresponding author on request.

Declarations

Ethics approval and consent to participate

Ethics approval and consent to participate in the written informed consent were obtained from each participant. The Ethics Committee of Tarbiat Modares University, Tehran, Iran, approved the study. The ethical code is IR.MODARES.REC.1402.251.

Consent for publication

All detailed data publication is most welcome.

Competing interests

The authors declare that they have no competing interests.