**3.1. Ergonomics for persons with disabilities**

evaluating every field and activity [42]. Ergonomic problems that occur during the working life of people with physical disabilities should be solved with the participation of many disciplines. Ergonomics is a multidisciplinary approach which addresses many disciplines as engineers, physicians, psychologists, physiotherapists, ergotherapists, architects, home economists and other disciples who have knowledge about anatomy, biomechanics, psychology, physiology, engineering principles, anthropometry, and kinesiology and the ones who solve

The main physical problems that may arise as a result of interaction between human, environment, and equipment are musculoskeletal diseases [41]. Work-related musculoskeletal disorders refer to musculoskeletal disorders that affect work environment and work performance significantly. Workplace risk factors are thought to develop work-related musculoskeletal disorders with personal characteristics and social factors [46]. Jobs with multiple risk factors or increased working at high-risk conditions will increase the likelihood of having a musculoskeletal system disorder [44]. Repeated hand tasks with heavy work, heavy lifting, pushing heavy objects, pulling or carrying, long sitting in poor posture, monotonous work, inadequate intermittent rests, vibration, or cooling are the main risk factors [41]. The level of risk generated is determined by the severity of exposure to the risks, frequency, duration, and strength

Inadequate working postures in jobs that require intense labour force cause inefficiency as well as musculoskeletal discomfort [41, 44, 47]. One of the aims of the ergonomics is to improve worker postures and balance worker capabilities and work requirements, resulting in improved worker safety, health, and overall productivity of the system [41, 44, 47]. Workplace injuries cause a decrease in one's work capacity and production [41, 44, 47]. While these injuries cause discomfort, reduced work capacity, and production affect economics negatively [44]. Therefore, the role of preventive rehabilitation becomes increasingly important in preventing these injuries and having a healthy musculoskeletal system [44]. One of the mechanisms of injury that is resulted from many risk factors is muscle loading [43, 48]. In poor working posture, degenerative changes occur in the affected joints and in the connective tissue [43, 48]. Repetitive movements and inadequate rest periods cause discomfort caused by muscular loads together with degenerative changes resulting from poor and bad posture [43, 48]. Another mechanism of injury that occurs during exercise is muscle fatigue. Static and dynamic loading resulting in muscular work with maximum capacity leads to muscle fatigue [43, 48]. Points to consider when designing a workplace to avoid work injuries are listed below [49]:

**1.** When the person is working, he should provide a straight and face-to-face posture.

head and neck are upright or only when the head is tilted slightly forward.

safe postures without diminishing the capacity.

supports must be adjusted accordingly.

**2.** If the vision is required during a job, the required work points should be visible when the

**3.** All business activities should allow one to work with many different but equally healthy,

**4.** Work should be arranged in such a way that the person must be standing or sitting in position according to his wishes. While sitting, both feet should have equal load, and the foot

stress factors at home, school, and workplace [17, 45].

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capacity of the person to meet other job requirements [44].

Ergonomic arrangement of a workplace is done by making the work suitable for the person to be worked on. Although the employee is selected according to his/her ability according to the work to be done, it is very important that the place to work matches the physical and psychological characteristics of the employee [44, 45]. 'Appropriate Settlement' was first used in 1990 to prevent discrimination against the people with disabilities and to remove the barriers to employment [14]. This term includes [1] provision of assistive equipment necessary for the job to be done, [2] modification to make the business environment fully accessible, [3] arrangement of the workflow, and [4] provision of personal assistance when needed. Unreachable workstations constitute a physical barrier, and if the workspace is not modified, it will prevent the desired work [7, 14]. Some workplaces are affecting the physical condition negatively due to the work they have installed on the person, which can reduce the person's independence both at home and in daily life [1, 14]. The person may not be able to keep the job any longer and then may be forced to another job or not to work at all.

Providing the necessary tools to do the job is a step in removing the barriers at the workplace [14]. Easy access to computer technology, software that understands speech, ergonomic keyboards, and mouth-controlled mice are frequently used in many disability groups [14]. In fields where computer technology is not used, envelope folding machines, electrical staplers, telephone headsets, and similar equipment can be useful for productivity [14]. Another step in lifting the barriers is to organize the physical work environment both personally and in general [14]. Business areas should be well illuminated, crossing areas should be expanded, maneuvering areas should be separated, and entrances without stairs should be provided [14, 44]. The regulation of the workflow is also important in ensuring accessibility [14, 44]. It should be ensured that the energy of the person is activated by arranging activities that are not necessary for the business [14, 44]. For example, placing frequently used equipment in close proximity, or lowering shelves where heavy items are placed, prevents the occurrence of fatigue and walking difficulty [14]. In addition, to find the appropriate time to take a break without interruption and to change among employees in monotonous work are the steps that can be taken in order to streamline the workflow [14]. Some employees may need physical help despite all the arrangements [14]. Office design should be done in such a way that employees can help each other when needed or a place where an assistant can work if required [14].

**1.** Physical factors

*3.3.1. Physical factors*

and tendon sheath [41].

*3.3.2. Environmental factors*

*3.3.3. Psychological factors*

considered [41, 44].

and initiatives [41, 53].

**2.** Environmental factors **3.** Psychological factors

Repetition of the same movements during work, improper postures, static posture, excessive use of force, and squeeze are the physical dimensions of the ergonomic risks. Repetitions of the same or similar movements during work can cause pain and discomfort in the musculoskeletal system because the muscles are not given enough time to rest [41]. Natural postures are the safest and most convenient way to work. Non-natural postures force the physical limits of the body by putting pressure on the muscles and joints. The long standing of the worker in the same position limits the blood flow and makes the muscles tired and injured. The excessive force applied to the muscles causes the muscles to contract more than normal, causing the joints to overload and cause injuries. Compression of the soft tissue between a bone and a hard or sharp object reduces blood flow and nerve conduction, damaging tendon

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Noise, temperature, humidity and airflow, lighting, vibration, and chemicals are among the ergonomic risks. The organizer of the workplace should also pay attention to environmental factors. The obligation of the human body's limits, job requirements, and the characteristics

The body of a working person may be exposed to certain environmental factors. Environmental interactions above the limits can cause different body parts, leading to cumulative trauma. The use of vibration absorbing equipment, the use of extreme cold or hot barriers or insulation clothing, the construction of barriers where there is airflow, and the introduction of a crusher on the computer screen for reflected light can reduce the environmental impacts of

Psychological risk factors include mental overload, psychosocial effects, social communication in the workplace, and organizational influences. It has been determined that these factors, which include all employees and employers, increase ergonomic risk and should therefore be

Many musculoskeletal system diseases that involve the abdomen, neck, upper extremity, and lower limbs in our country are accepted as occupational diseases in the law [41]. However, data on the frequency of these diseases, risk factors, workday loss, insurance indemnity, and cost are not available [41]. Work-related musculoskeletal diseases, which are among the most important problems of employees and which reduce work efficiency, and prevention of adverse effects of these diseases are possible with ergonomic education

of the equipment means to ignore the role of the environment.

the body through simple, non-costly measures [41].

Different studies done by Belgen et al. [50] and Çalık et al. [51] reported that the majority of people with disabilities work with high-risk posture and this creates risk of musculoskeletal problems [50, 51]. An employer who will hire a person with physical disabilities should follow a conscious attitude to what positions he or she will be employed and the places in which the person concerned will be interested. It is aimed to create the work to be done with the ergonomic arrangement to ensure the employee's harmony with the work environment [42, 44, 45, 50, 51]. This is only possible when anthropometric point of view, physiological point of view, psychological point of view, information point of view, and safety point of view are all considered [42, 44, 45]. Only when all these conditions are met, the person can perform all the necessary activities appropriately [42]. Conditions that are often neglected for people with disabilities are anthropometric, physiological, and psychological conditions [45].
