Subjects

Within the scope of this project, employees of various inclusive businesses will be examined. These businesses include a laundry service with 122 employees, a company in the field of office services and document management with 64 employees and a fitness and health centre with about 15 employees. The proportion of people with disabilities in the inclusive companies is between 43% and 48%. Furthermore, employees of a sheltered workshop with 337 employees (approximately 91% with disabilities or health impairments) will be analysed.

In the laundry service and fitness and health centres, the employees mainly work in a standing position, e.g. on an assembly line, while those in the office services and document management, as well as in the sheltered workshops, mainly work in a sitting position.

The following inclusion and exclusion criteria apply:

Inclusion criteria:

Employees of the companies mentioned.

People with and without disabilities (physical and mental disabilities, i.e. deafness, learning disorder or employees returning to work after serious illness or injury).

Voluntary participation, declaration of consent.

Participants have full legal capacity and understand the nature, scope, significance and consequences of the examination.

No current injuries of the musculoskeletal system.

Exclusion criteria:

A signed consent form will be obtained from all participants. This form includes comprehensive information about the objectives and the course of the study as well as personal rights and data protection. The above-mentioned aspects will be discussed together in a personal interview and on the informed consent form. Due to the heterogeneity of the participants, the clarification will be adapted to the individual challenges (comprehension problems e.g. due to cognitive, intercultural characteristics) (e.g. easy language).

An approved ethics application from the Department 05 of the Goethe University Frankfurt (2022-57) is available for the implementation of the studies.

Risk analysisDGUV checklist

The risk analysis should be carried out using the “Checklist for orienting risk assessment for musculoskeletal system loads” from DGUV Information 208 − 033 [20]. The DGUV checklist enables a quick and simple assessment of the physical types of stress that can be used to identify focal points of stress. It also provides an orienting clarification of the question of whether there is a need for action, e.g. an in-depth analysis or measures to be taken to reduce the load.

MVN Awinda

The MVN Awinda motion capture system is a person-based system that uses 17 inertial motion sensors, each consisting of accelerometers, gyroscopes and magnetic field sensors, to provide positional or angular information of the entire human body. The system’s sampling rate is 60 Hz and the measurement error is specified by the manufacturer as ± 1%. The measurement system works wirelessly and the data is transmitted by radio. The sensors are attached to the body parts with the help of adhesive tape. In contrast to the MVN Link system in which wired sensors are attached to a full-body suit, this method offers a large degree of flexibility in handling so that individual and anthropometric differences can be optimally taken into account, especially before working with people with disabilities. In contrast to the gold standard optical motion tracking, this inertial motion capture system provides reliable data, ranging from good to excellent, in line with concurrent research, particularly in the frontal and sagittal planes [21, 22].

Ethnographic observations

Observational studies will be carried out in the selected companies in order to elicit the procedures and requirements of the work processes using a descriptive approach. All persons present in the company will be informed about the aims and the course of the ethnographically designed observations. The observations do not collect personal data but refer to the work processes themselves. They are divided into two parts. The first one contains observations with immediate field notes, that are added by memos afterwards. During the second part the observations are made by accompanying one employee for a few hours. This employee is questioned about the work he or she is doing. Field notes and memos are prepared afterwards.

Guideline-based interviews

Guided interviews will be conducted with the management of the participating companies. These interviews are oriented along three thematic blocks relating to basic structures, inclusive companies and management style. The aim is to obtain an initial overview of the company and management structures and to discover which company health measures are or were a regular part of everyday working life. Following the observations, guided problem-centred interviews will be conducted with selected employees of the companies. In this way, it is possible to learn more about the subjective views of the employees.

Especially in interviewing mentally disabled people, the use of standardised methods validated via tests with non-disabled people is often limited because the possibilities to flexibly respond to the individual relevance criteria of the respondents are reduced with the increasing standardisation of the survey [23]. In general, follow-up questions and interpretation are necessary and misunderstandings have to be excluded. The basic prerequisite for surveys with mentally handicapped people is, therefore, a precise knowledge of the life situation of the interlocutor and the illustration of what is meant in a form that the interlocutor can understand [24]. This results in the focus of a subject-oriented approach in combination with an ethnographic approach. However, this makes it absolutely necessary to first get to know the persons to be interviewed personally in order to establish a basis of trust and to clarify the meaning and purpose of the research [25]. The selection is based on the specifics of the activity, personal data (type of impairment) and the willingness to participate. Interviews will ask about experiences and impressions of work activity (e.g. stresses, strains, routines, organisation, social hierarchies) and health (e.g. well-being, pain). In the interviews, personal (e.g. motivation, wishes), structural (e.g. tasks, scope, work equipment) as well as social content areas (e.g. interaction with colleagues) are to be made the subject of discussion. The interview data is transcribed by a service provider. The evaluation will be based on the Grounded Theory [26, 27].

Questionnaire of musculoskeletal complaints

In order to be able to analyse the health of the employees more comprehensively for the recording of potential correlations between surveyed work-specific physical stresses and physical complaints or pain of the employees, a quantitative survey of physical complaints or pain is to be carried out by means of a questionnaire in addition to the qualitative survey of health. Furthermore, personal data such as height, weight, age, gender and the types of any limitations will be collected via the questionnaire and subsequently pseudonymised.

Since it is not possible to refer to questionnaires validated “in the inclusion setting”, the aim is to develop and validate a new questionnaire. In the development of the questionnaire, the focus was mainly on elements from the Nordic Questionnaire [28]; this questionnaire has been an internationally recognised and widely used questionnaire for the assessment of musculoskeletal complaints for more than 30 years. It has been validated several times [17, 29, 30] and there are comparative data available from administrative occupations [31,32,33,34], factory workers [35,36,37,38] or employees in health care occupations [39,40,41,42]. In this project, the revised German version of the Nordic questionnaire on musculoskeletal complaints [43] from the Federal Institute for Occupational Safety and Health serves as a template. Furthermore, in addition to elements of the Nordic Questionnaire, elements from the German Pain Questionnaire are also to be used which appear to be simpler and easier to understand for implementation by people with disabilities.

Besides the translation into easy language, the adaptation to the target group’s understanding of the text (especially regarding the meaning of pain) is mandatory. For this purpose, participatory interviews on the questions of the questionnaire are planned. Validation will be carried out via piloting with selected people with disabilities.

Study procedure

The plan is to conduct an exploratory baseline study in the companies listed above, focussing on their respective professional activities. Job requirements include sedentary desk work in an office or gym, fine motor work in a sitting or standing position in a sheltered workshop, repetitive tasks performed in a standing position in assembly work, or physically intensive work in physical therapy. A triangulated combination of qualitative and quantitative methods (mixed-methods design) will be used to record the physical and mental health burden. From the outset, a participatory approach will be pursued in which the research will not be conducted about, but rather with, those affected, in close accordance with DGUV Information 215 − 112 [17].

First of all, the literature research is to be extended since the previous literature research did not reveal any or very few relevant studies on health measures in inclusion companies and workshops for people with disabilities. In this context, already successfully implemented improvements of workplace situations (in the form of best-practice examples) are to be identified.

Initial workplace inspections and surveys of the occupational safety and health stakeholders are planned on site in the inclusive companies in order to obtain initial findings with regard to physical and mental stressors, other risk factors and resistance resources in the inclusive context that achieve productive and preventive effects.

The identification of increased physical stresses for the musculoskeletal system is to be carried out using coarse screening (DGUV checklist [20]). The DGUV checklist provides an orientational risk assessment in the six physical load types of lifting, holding and carrying loads, pulling and pushing loads, manual work processes, exertion of whole-body forces, forced body postures and body continuation. In addition, hand-arm and whole-body vibration will be examined. In order for the coarse screening to be applied in a meaningful way, it is first necessary to learn about and understand the overall work processes in the participating companies. In this way, the manual activities of the respective workstations are to be objectified and potential risk factors identified within the framework of job observations and surveys of potential ergonomic risks.

The DGUV checklist is then to be applied in selected work steps to identify the types of exposure and rough exposure levels. For this purpose, the investigators will take on an observing role and carry out the analysis by observing the activities while the study participants are carrying them out undisturbed.

If increased loads and, thus, potential hazards are identified, then this will be followed by a differentiated ergonomic risk assessment of selected load focal points of the measurement data collected by means of motion capture procedures based on inertial sensors (MVN Awinda). The exposure assessment will be carried out using established occupational science and biomechanical procedures, both from the category of screening procedures, in which a rough assessment of types of stress is carried out (e.g. rapid upper limb assessment (RULA) [44], key indicator methods and the DGUV checklist from the MEGAPHYS project [45]), and from the category of measurement procedures which allows a localisation-specific risk assessment of the continuously collected measurement data (CUELA assessment procedure, MEGAPHYS [45, 46]). To record possible subjective complaints in the musculoskeletal system, a modified questionnaire (variations of the Nordic Questionnaire) was designed and evaluated specifically for the needs of the employees (easy language, supportive communication). This questionnaire will make it possible to identify correlations between subjectively perceived complaints and objectively measured stresses in specific body regions. Following validation, the questionnaire will then be used for surveying the employees of the cooperating companies. Translators will accompany the practical implementation if, for example, non-native speakers are interviewed or sign language is required.

In addition, participatory observations lasting several weeks are to be carried out in order to gain in-depth insights into everyday work processes and to establish personal ties with the employees as a prerequisite for a subsequent survey. Based on DGUV Information 206 − 026 on mental stress [47], this will be implemented via problem-centred interviews and also within the framework of participant observations (interview notes, memos, etc.). The survey is intended to record the subjective well-being at the workplace. For this purpose, aligned guideline-based interviews are planned which are to be developed and used in this phase. The planning and implementation of the analyses is to be carried out in close coordination with the occupational health and safety actors.

Based on the results of the workplace analysis and the survey of the physical and mental state of health, conclusions are to be drawn about potential health hazards for the employees. In addition, specific workplaces are to be identified in which exemplary measures can be implemented. These measures will then be implemented in consultation with the respective plant management and with the involvement of the employees. Possible starting points here could be the ergonomic redesign of workplaces (work equipment, work furniture, room concept, noise and lighting conditions), target group-appropriate instructions for healthy behaviour (e.g. video clips on chair adjustment) or the visualisation of body movements and postures (e.g. via Xsens or CUELA). The objective here is to examine whether and to what extent proven concepts from non-inclusive workplaces can be transferred to inclusive workplaces or which adaptations of these concepts are necessary for use in inclusive workplaces. The implementation and evaluation of the implemented measures will be surveyed in the respective inclusion companies over a period of approximately 6 months (pre-post control group design). The results of the evaluation will be used to draw conclusions about the applicability of the modified analysis methods and the transferability of the implemented intervention measures (transfer of best-practice examples). Recommendations for action are to be derived from the findings with the aim of achieving a high degree of transferability and easy implementation in operational practice. Since this project focusses on the analysis of “classic” occupational activities (office work/assembly work/stand-up work), which often correspond to the work requirements in inclusive companies a high degree of transferability to other companies can be assumed.

Evaluation parametersDGUV checklist

The presence of an increased load in one or more of the examined load types.

Measuring analysis

The motion data acquired with MVN Awinda will be used to analyse the load for the body regions neck/cervical spine, shoulders/upper arms, elbows/lower arms, wrists/hands, lower back/lower spine, hips and knees, as well as to analyse the cardiovascular system and energy metabolism, and to evaluate all these with a view to possible health hazards. For this purpose, the movement data will be further processed with proprietary software [45, 47] to determine the relevant biomechanical and physiological load parameters over time:

Body angles and angular velocities (e.g. tilt/lateral tilt/torsion of the head and trunk, flexion in the knee, hip, shoulder, elbow and wrist joints).

Estimation of joint moments (e.g. shoulder joint or lumbar spine at L5/S1).

Estimation of intervertebral disc compression forces in the lumbar spine in the L5/S1 region.

Working heart rate.

Energy metabolism.

The assessment of the exposure data will be based on:

Questionnaire.

− 12 months’ prevalence and frequency per body region.

Duration of complaints.

Influence of profession.

Cause of complaint.

Interviews

The survey method of guided interviews will be used to collect data. The subsequent evaluation will be carried out with the help of Grounded Theory.

The interviews with the companies’ managements will be collected with the help of the procedure of problem-centred interviews and the Grounded Theory, and will be evaluated via the categories of basic structures, inclusion companies (tasks and duties regarding WHP) and management style. The guideline for the interviews with the employees of the companies follows the deductive structuring into work processes, experiences and specific conflicts and adaptations to the work requirements and the employees’ own handling of health or physical complaints. In addition, the self-image of inclusive companies and the perception of hierarchical structures are addressed in accordance with the survey of the management level.

Additionally, the interviews also serve to involve people with disabilities in the process. Through the interviews they are able to share their subjective view on (dis)ability, the workplace and health. In this manner every other part of the research process includes these statements in their solution finding process.

Statistical analysis and sociological evaluation of the interviews and observations

The project intends to do this in accordance with an inclusive understanding, together with the greatest possible openness to the needs of the people working there. For this reason, a precise indication of the sample size is not yet possible, at this point, as participation can only be voluntary. In order to win over as many of the employees as possible for participation, a detailed explanation to the employees will take place, in consultation and cooperation with the BWMK works council, before the data collection begins. The aim (which is, according to the “Behinderten Werk Main-Kinzig” interviewees, a realistic one) is for at least 50% of employees to participate.

DGUV checklist

This is a dichotomous parameter that is used to assess roughly the physical risk. Only descriptive methods are used for this purpose.

Measurement analysis

After processing the kinematic data with the Xsens software, the joint angle data are further processed in user-defined files using MATLAB® software vR2020a (The Mathworks Inc., Natick, MA, USA). For ergonomic risk assessment of the recorded kinematic data, the RULA algorithm was applied using a code developed by Maurer-Grubinger et al. [44]. Further details on this script can be found in Maurer-Grubinger et al. [44].

In order to compare the joint positions or joint angles during the examination period, an inferential statistic for continuous data will be used. This statistic is based on the application of confidence intervals and uses the statistical parametric mapping (SPM) procedure.

All test procedures to be used are two-sided and are subject to a 5% significance level.

Questionnaire

The survey questions consist of nominal and ordinal scales. Descriptive and inferential statistical methods will be applied for the statistical analysis. The Chi-square test will be used for testing differences, with a significance level of 5%. Since both individuals with and without disabilities perform the same occupational activities in the participating companies, a direct workplace comparison is possible using all the survey methods employed.

Interviews and observations

The qualitative data from the interviews and observations will be analysed based on the Grounded Theory approach using a multi-stage coding process. Due to the integration of qualitative and quantitative methods, the theory formation is not entirely inductive and theory-free. However, given the exploratory nature of our study design, this approach is considered appropriate. The observations, development of guidelines, conduct of the interviews and analyses will be carried out in a circular and non-linear manner, as is common in qualitative research.

The basic step is initially the Open Coding which involves an initial, unbiased review. Categories resulting from this step are analysed in the second step, Axial Coding, for their interconnected meaning. In the third step, which involves further abstraction, initial hypotheses can be formed, thus leading to broader conclusions. Furthermore, the categories will be continually summarised throughout the process, ultimately crystallising into key categories. The inherent intention of identifying a core category in the theory will not be pursued due to the diverse focal points of the research questions.