Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention

*Daniel O. Odebiyi and Udoka Arinze Chris Okafor*

#### **Abstract**

Musculoskeletal Disorders (MSDs) affect body parts, with severity ranging from mild to intense. When MSDs develop in occupational settings, sequel to the physical tasks involved in the performance of work and the condition of the work-environment, they are referred to as work-related musculoskeletal disorders (WMSDs). The development and prognosis of any particular MSDs are modified by multiple risk factors, which are physical, individual, and psychosocial, in nature. None of these factors act separately to cause WMSDs, rather, they interact. The goal of ergonomics is to create an ergonomically sound work-environment, with the view to reducing the occurrence of WMSDs. This is premised on adherence to effective workplace ergonomic principles (WEP). By and large, WEP is more effective when done both at the workplace and during the performance of leisure time activities. Often, WEP involves designing the workplace, with consideration for the capabilities and limitations of the workers, thus promoting good musculoskeletal health, and improving performance and productivity. For favorable outcomes, a three-tier hierarchy of controls (Engineering, Administrative, and use of Personal Protective Equipment) is widely accepted as a standard intervention strategy for reducing, eliminating, or controlling workplace hazards. Failure of this strategy will expose workers to WMSDs.

**Keywords:** musculoskeletal disorders, workplace, ergonomics principles, injury prevention

#### **1. Introduction**

Musculoskeletal disorders (MSDs) is used to described injuries or disorders of the musculoskeletal system, like muscles, nerves, tendons, ligaments, joints, and cartilage; including the supporting structures of neck and back, and can affect all parts of the body (**Table 1**). Musculoskeletal disorders are described as Work-related, i.e. Workrelated Musculoskeletal Disorders (WMSDs) when they are caused, and/or made worse or persists longer than expected, by the performance of work/task, vis-a-vis., workenvironment and work-conditions [1]. According to the Bureau of Labor Statistics (BLS), MSDs represent one of the largest work-related problems in the United States; with the incidence rate higher among male full-time workers compared with females [2]. And according to the 2020/21 Labour Force Survey (LFS) of the United Kingdom,


#### **Table 1.**

*Common musculoskeletal disorders.*

470,000 workers are suffering from WMSDs - new or long-standing [3]; the occurrence and pattern of WMSDs in the United Kingdom are as shown in **Figure 1**. In Nigeria, WMSDs are especially prevalent in certain occupational sectors and industries such as transportation, warehousing, manufacturing/petroleum industry, health care, Communication services, Butchers, agriculture, and construction services [4–9].

Work-related Musculoskeletal Disorders are classified according to the affected musculoskeletal/anatomical structure (**Table 1**). According to the Bureau of Labor Statistics (BLS), MSDs accounted for 32% of all injury and illness cases in 2014 among full-time workers [2]. Work-related musculoskeletal disorders usually develop over time, in form of cumulative micro-traumas, sustained while working; it development can also be episodic. Additionally, the severity can progress from mild (i.e., Occasional) to severe/intense (i.e., chronic). These disorders are seldom life-threatening but they impair the quality of life of a large proportion of the adult working population.

The National Institute for Occupational Safety and Health (NIOSH) defined WMSDs as those diseases and injuries affecting the musculoskeletal, peripheral nervous, and neurovascular systems and are caused or aggravated by occupational exposure to ergonomic hazards [10]. Ergonomic hazards refer to physical stressors and workplace conditions that pose a risk of injury or illness to workers' musculoskeletal system. Ergonomic injury risks include repetitiveness and pace of work (i.e., repetitive motions), forceful motions, vibration, extreme temperatures (especially cold conditions), awkward work-posture and movements, caused by the inadequate design of work-stations, tools or other work equipment, and by improper work methods [11]. Other risk factors include, lack of influence or control over one's job, increase pressure (e.g., to produce more), lack of or poor communication, monotonous tasks,

*Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

**Figure 1.** *Occurrence and pattern of work-related musculoskeletal disorders [3].*

and perception of low support (e.g., management or co-workers). Furthermore, MSDs have been reported to be associated with reduced work ability, and decreased productivity among workers, across working populations [4, 7–9, 12–14]. According to the Bureau of Labour Statistics of the Department of Labour, MSDs is the diseases and/or disorders of the musculoskeletal system, and connective tissue, when the event or exposure leading to the case is bodily reaction (e.g., bending, climbing, crawling, reaching, twisting), overexertion, or repetitive motion [15]. They are not the result of any instantaneous non-exertion event like slips, trips, falls or similar incidents.

The occurrence of WMSDs has been attributed to the exposure of workers (employees) to physical factors at work, as a result of poor and/or none adherence to Work-place Ergonomic Principles (WEP). The occurrence of WMSDs are basically attributed to the performance of work, and work-environment, furthermore, MSDs are usually made worse and/or longer lasting by work conditions that preclude good ergonomic principles during execution. Therefore, adherence to WEP is essential in preventing the occurrence of WMSDs. Work-place ergonomic principles involves identifying, analyzing, and controlling work-place risk factors, for the purpose of preventing and/or reducing the occurrence of MSDs (i.e. soft tissue injuries), caused by performance of work, vis-a-vis, exposure to sudden or sustained force, vibration, repetitive motion, and awkward posture etc. This is achieved by creating an ergonomically sound work-environment. By and large, adherence to effective WEP helps to create a workplace condition and job demands, that is, at the capacity of the workers (working population), and thus can be very helpful in preventing/reducing WMSDs. Work-place ergonomic principles is particularly recommended in the conduct of all type job descriptions; including materials manual handling, office-work, and patients management, and rehabilitation.

This book chapter is based on detailed literature of the causes and prevention of WMSDs. It described the inherent workplace hazards, workers are exposed to, at

the different work-environments; and the benefits of effective preventive strategies, using standard ergonomic principles (i.e., WEP), applicable for materials manual handling work-place, and during patients management/rehabilitation.

#### **2. Musculoskeletal disorders – causes and prevention**

#### **2.1 Background**

The disorders/injuries of the soft tissues of the musculoskeletal system - muscles, nerves, tendons, ligaments, joints, and cartilage, are commonly referred to by many names, including musculoskeletal disorders (MSDs), repetitive strain injuries (RSI), repetitive motion injuries (RMI), cumulative trauma disorders (CTDs) and overuse injury [16]. The problem with using other terminology other than MSDs, is that they appear to suggest a singular causative factor (e.g. repetition or stress) as the cause of the soft tissue disorders. This is restrictive, because the literature points to multiple causative risk factors for MSDs. The World Health Organization (WHO), has reported that WMSDs has multi-factorial aetiology; indicating that a number of risk factors contribute to causing these disorders [17, 18]. These factors are physical, work organizational, work-environment, work-conditions (i.e. repetition, sudden/forceful exertions - like lifting a heavy object, and repetitive/sustained awkward postures), psycho-social, individual, and sociocultural, in nature [17]. This multi-factorial aetiology is the major reason for the controversy surrounding WMSDs – as both multiple and individual factors have been identified in the development of WMSDs [17, 18]. The development of MSDs has been recognized as having occupational aetiology factors as early as the beginning of the 18th century [1]. However, it was not until the 1970s that occupational factors were examined using epidemiologic methods, and the work-relatedness of these conditions began appearing regularly in the international scientific literature [1].

#### **2.2 Causes of musculoskeletal disorders**

The musculoskeletal system (i.e., muscles, nerves, tendons, ligaments, joints, and cartilage) are most effectively utilized, when they are exposed to little or no workplace risk; i.e. one that is within the worker's capability. The level of risk depends on the intensity, frequency, and duration of the exposure to these work-place risks/hazards. Furthermore, the effects of work-place risks may be amplified by organizational factors such as shift work, work pace, imbalanced work-rest ratios, demanding work standards, lack of task variety etc. Subjecting a worker to work (carry out a task), in an ineffective WEP, is making the worker to work outside his/her body's capabilities and/ or limitations. Simply put, the worker is being asked to put his/her musculoskeletal system at risk. This may lead to body fatigue in the workers, beyond their ability to recover, and which may result in musculoskeletal imbalance, and may eventually, lead to the development of MSDs . Thus, exposure to work-place risk factors, as a result of ineffective WEP, puts workers at risk of developing MSDs (**Figure 2**). According to the Bureau of Labour Statistics of the Department of Labor, the diseases and/or disorders of the musculoskeletal system (and connective tissue) is described, when the event or exposure leading to the case is bodily reaction (e.g., bending, climbing, crawling, reaching, twisting), overexertion, or repetitive motion [15]. As a matter of facts, "… there is an international near-consensus that MSDs are causally related to occupational *Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

#### **Figure 2.**

*Mechanism development of MSDs.*

ergonomic stressors, such as repetitive and stereotyped motions, forceful exertions, non-neutral postures, vibration, and combinations of these exposures" [19].

Work-related Musculoskeletal disorders do not result from instantaneous nonexertion events like slips, trips, falls etc. The main cause of WMSDs is exposure to (ergonomic) "Risk Factors" at the work-place. Thus, the disposition for developing WMSDs is related more to the difference between the demands of work and the worker's physical work capacity, which decreases with age [20]. Therefore, adherence to an effective Work-place ergonomic principle/design is essential in the prevention of the development of MSDs. Epidemiological studies [1, 21] have categorized workplace ergonomic risk factors into three, namely: (a) Physical factors (like sustained or awkward postures, repetition of the same movements, forceful exertions, hand-arm vibration, all-body vibration, mechanical compression, and cold) (b). Individual factors (like age, gender, professional activities, sport activities, domestic activities, recreational activities, alcohol/tobacco consumption and, previous WMSDs), (c). Psychosocial factors (like work-pace, autonomy, monotony, work/rest cycle, task demands, social support from colleagues and management and job uncertainty). In this book chapter, ergonomic risk factors are broadly divided into two categories: work-related (ergonomic) risk factors and individual-related risk factors.

#### *2.2.1 Work-related risk factors*

This is further divided into two - Primary and secondary factors. There are three primary work-related (ergonomic) risk factors, which are basically physical in nature:


*Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

#### **Figure 3.**

*Work-related musculoskeletal disorders risk factors.*

motions with the wrist in an extended position, and in a constrained postures, such as playing a musical instrument or typing. Exposure to this risk factor, in combination with other risks factors like repeated exposure to force, vibration, awkward posture or repetitive lifting of heavy objects in extreme or awkward postures, can lead to increased fatigue, and subsequent musculoskeletal imbalance. This will eventually leads to the development of MSDs, as fatigue continues to overturn recovery, over time. For instance, combined exposure to prolonged sitting in awkward postures may increase the risk. Exposure to these workplace risk factors puts workers at a higher level of MSD risk. That is, high task repetition, forceful exertions and repetitive/sustained awkward postures, fatigue the worker's body beyond their ability to recover, leading to a musculoskeletal imbalance and eventually an MSD.

**NB:** The risk of developing MSDs increases with increasing number of (ergonomic) risk factors involved/present in the execution of the job-task. Jobs that combine high force and high repetition, in awkward postures, pose the greatest risk.

*Secondary Risk Factors:* These include psychosocial factors [like work-pace, autonomy, monotony, work/rest cycle, task demands, social support from colleagues and management and job uncertainty]. Other secondary risk factors include: Static Posture, Contact Stress, extreme temperature [Cold/heat], Vibration, Noise, Physical Stress, Emotional Stress.

#### *2.2.2 Individual-related risk factors*

When all work-related (ergonomic) risk factors are addressed, it is imperative that consideration be giving to individual risk factors, in addition to work-related (ergonomic) risk factors; more so because human beings, are multi-dimensional in nature. This is because limitation to a singular cause of MSDs will limit the ability to create a prevention strategy that addresses the multi-dimensional nature of the workers (and their work-environments). Individual risk factors include:


NB: It is imperative to note that, in other to ensure proper balance of work-practice, and subsequently reduce the occurrence of MSDs, both work-related (ergonomic) risk factors, and individual-related risk factors should be adequately evaluated and controlled. And in addition to the adequate control of work-/individual-related risk factors, there is also need for the workers to exhibit: proper work-practice, good health habits, adequate rest (that allows adequate recovery), and a good nutrition, and fitness regimen, otherwise, they will be at greater risk for fatigue, which may outrun their recovery system. Also, having a poor overall health profile, may put workers at greater risk of developing musculoskeletal imbalance and eventually MSDs.

#### **2.3 Prevention of musculoskeletal disorders**

Truly, work-place injuries are not inevitable. Therefore, a work-place design plays a crucial role in reducing the development of MSDs in a work-place; and this can be achieved through the application of an effective work-place ergonomic principles (WEP). The main goal of an effective workplace ergonomic principles WEP is to develop or modify work-environment to meet workers' needs. The design of WEP is directed towards improving ergonomic risk factors in the work-place, following a proper ergonomic evaluation of the workstation design, worker's capabilities, workers' physical attributes and habits. The development and implementation of work-place ergonomic controls is based on the correct assessment of the ergonomic risks inhering in the execution of task, with the designs directed to reducing these risk factors.

#### **2.4 Developing and implementing workplace controls**

An adequate "prevention strategy", with better outcomes is usually conducted following a holistic evaluation of the work-environment, work-task, and the worker. The evaluation of any work-task (Job), vis-a-vis., workplace (including Tools), Tasks and workers, should necessarily involved identifying Ergonomic Stressors, like the:

i.*Force required to complete the task* - whether the completion/execution of the task involves assumption of static-working or awkward postures.

*Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*


For adequate outcomes, a three-tier hierarchy of controls (of Engineering, Administrative and use of Personal Protective Equipment), is widely accepted as an intervention strategy for reducing, eliminating, or controlling workplace hazards, including ergonomic hazards. These are:

#### *2.4.1 Engineering controls*

This entails, designing the job-task, to take account of the capabilities and limitations of the workers using engineering controls. Engineering improvements/controls include:


#### *2.4.2 Administrative controls*

This involves changing the work practices and management policies, with the view of reducing prevailing workplace risks. Administrative control strategies are policies

and practices that reduce WMSDs risk but they do not eliminate workplace hazards. Administrative controls are usually employed as a temporary measures until engineering controls can be implemented or when engineering controls are not technically feasible. Administrative improvements/controls include:


#### *2.4.3 Personal protective equipment (PPE)*

Also known as Safety gear, PPE, generally provides a barrier between the worker and hazard source. Examples of PPE include: Respirators, ear plugs, safety goggles, chemical aprons, safety footwear (shoes), hard hats, knee and elbow pads. There are other devices (like braces, wrist splints, back belts, and similar devices), that are capable of reducing the duration, frequency, and/or intensity of exposure of risk factor for MSDs, although evidence of their effectiveness, as regarding offering personal protection against ergonomic hazards remains (i.e. injury reduction) inconclusive. In some instances, these devices may decrease one exposure, but increase another, because the worker has to "fight" the device to perform the work. An example is the use of wrist splints while engaging in work that requires wrist bending.

#### **3. Musculoskeletal health**

Soft tissues injuries (STI) of the musculoskeletal system are important cause of musculoskeletal ill health, particularly in working adult life. Thus, work may serve as a contributor to the development musculoskeletal ill health or exacerbator of an existing health condition. According to Health and Safety Executive (HSE),

WMSDs exert harmful effects on the life and well-being of workers in all fields, especially those requiring manual labor [24]. These injuries arise sequel to different causation:


Musculoskeletal health (MSH) means more than the absence of a musculoskeletal conditions. Good MSH implies that the musculoskeletal system (i.e., muscles, nerves, tendons, ligaments, joints, and cartilage) function well together without pain or discomfort. Thus, people with good MSH can carry out their functional activities (of daily living) with ease, and without discomfort. Poor MSH may be related to multiple risk factors like physical inactivity, being overweight or obese, diets deficient in vitamin D or calcium, smoking, older age and genetic predisposition to some musculoskeletal conditions [27]. Focusing on strategies directed towards reducing threats to MSH, sequel to work-place activities can therefore not be overemphasized; including early ergonomic evaluation of the work-place, to identify the risk (work-place/individual) factors; and early ergonomic intervention - directed at modifying physical work environments and work practices (**Figure 4**). This may be helpful in promoting MSH at the wok-place, and subsequently help prevent chronic pain, disability and work loss [28]. This is particularly important because there is a complex relationship between work and MSH. While it is true that certain types of work, and work-place conditions may have negative impacts on MSH, and may lead to failure to create a healthy environment and subsequently increase the risk of MSDs; undertaking meaningful work is an important part of an individual's sense of health and well-being [25]. Also, according to the National Institute for Health and Clinical Excellence (NIHCE), healthy workplaces provide an opportunity to promote good health generally, and musculoskeletal health specifically [26]. Furthermore, Waddell *et al.* [25] in their study titled "Work and common health problems", concluded that, overall, the beneficial effects of work outweigh the risks of work, and are greater than the harmful effects of long-term worklessness.

#### **Figure 4.**

*Workplace ergonomic control of work-related musculoskeletal disorders.*

#### **4. Ergonomics principles**

The definition of ergonomics (or human factors), as adopted by the International Ergonomics Association (IEA) in 2000 is "Ergonomics (or human factors) is the scientific discipline concerned with the understanding of the interactions among human and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance" [29]*.* Ergonomics is looked at from different perspectives; the word *"Ergonomics"* is derived from two words: *Ergon,* which means work and *Nomos,* which means laws. Ergonomics is also known as "human factors" and "human factors engineering". It supports the workers and their environment; vis-a-vis, the physical, psychological and social needs of the workers. Ergonomics is simply defined as the scientific study of human work (i.e., people at work). It is basically the science of fitting work-place conditions and job demands to the capability of a particular worker or working population, instead of fitting the workers to their work-place [1]. To achieve this, it important to consider the physical (and mental) capabilities, and limits of the worker as s/he interacts with the Tools/Equipment, Work methods, Tasks and Working environment. There are three major areas (or Dimensions**)** of ergonomics: Physical, Cognitive and Organizational (Environmental) aspects (i.e., dimensions) of ergonomics:

*Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

**Physical Aspect of Ergonomics:** Focuses on the physiological and bio-mechanical effects of work on human being e.g., Working postures, Work-stations, Work-related safety and health, Materials handled and Work-related musculoskeletal disorders.

**Cognitive Aspect of Ergonomics:** Focuses on the relationship between individual worker and the different systems (in the work-place) that workers (employees) operate with. It concerns the worker's cognitive processes, and the ability to process information, for instance technological solutions used at work.

**Organizational Aspect of Ergonomics:** Focuses on organizational processes, structures and policies at workplace, including communication within the workplace, working hours, work processes/methods and co-operation within operators.

#### **4.1 Work-environment**

Ergonomics is described in terms of the environment concerned, i.e. Work-Environments. Work is Physical or mental effort or activity directed towards the production or accomplishment of something (Task). It is the basis for skill acquisition; and is needed throughout all developmental stages for successful role function. While Environments include all the physical, chemical, and biological factors extended to human host, and all related behaviours, but excluding those natural environments that cannot reasonably be modified. Thus, Work-Environment describes: Circumstances, conditions, and influences that affect the behavior and performance of people/workers in the workplace. The following Physical factors affect job design - Noise, Vibration, Lighting, Temperature, Humidity, and Air Flow

#### **4.2 Categories of work-environment**

In terms of condition of job, there are two work-environments - *Office Work Environment (OWE)*, which specifically deals with the office environment; and *Industrial (Factory/Heavy-duty) Work Environment (IWE)*; which specifically deals with the Factory/Industrial environment.

While in terms of personality of the staff and/or management, there are also two categories: *Hostile Environment*, here, there appear to be little or no support what so ever, from the management and the direct boss. And *Friendly Environment*; here the workers received regular supports from the Management and their immediate boss. This may be created as an incentive for the workers.

#### **4.3 Benefits of ergonomics**

The primary goal of work-place ergonomics is to reduce workers' exposure to MSDs risk factors, thereby creating a safer and more healthful work environment. This is achieved through the use of effective WEP, which normally involves engineering and administrative controls. Work-place Ergonomics Principles (WEP) are directed towards designing workstations, tools and work tasks for safety, efficiency and comfort. This is ultimately, to prevent and/or control occurrence of MSDs, associated with the overuse of muscles (through force exertion), repeated tasks and assumption of awkward posture. Thus, effective WEP is directed towards preventing MSDs (injuries) by decreasing musculoskeletal imbalance and fatigue, associated workplace ergonomics risk factors like overuse of muscles (through force exertion), repeated tasks, and assumption of awkward posture; and failure

to the workers body's recovery system, due to the assault of the ergonomic risk factors. This will invariably, result in increasing comfort (of doing work), job satisfaction and safety (of worker and Tools). Other benefits of workplace ergonomic include:


iii.Increased efficiency at work.

iv.Reduced turnover (for both Machine & Human factor).

v.Reduced absenteeism.

vi.Reduced presenteeism

vii.Increased employee's morale.

viii.Decreased workers' compensation costs.

ix.Increased physical well being of the workers.

#### **5. Work-place ergonomics**

Work-place ergonomics involves designing the work-place, with consideration for the capabilities and limitations of the workers, with the view to reduce risk and promoting good musculoskeletal health; and consequently improve human performance and productivity, including office, recreation activities, and manual handling workplaces. According to General Duty Clause (GDC), Section 5(a)(1) of the Occupational Safety and Health Act (OSHA) regulation of 1970, employers have an obligation to keep the workplace free from recognized serious hazards (including ergonomic hazards), although OSHA regulations do not mandate an employer to provide ergonomic equipment such as work stations and chairs [30]. Common work-place risk factors (i.e., ergonomic hazard) include: Poor sitting posture, Awkward posture, Prolonged (stationary) positions, repetitive movements, Poor lifting (material handling), force/mechanical compression/vibration, temperature extremes, glare, inadequate lighting, and duration of exposure.

#### **5.1 Ergonomic hazards at the office workplace**

#### *5.1.1 Poor (Sitting/standing posture)*

Assumption of neutral postures when sitting (**Figure 5a** and **b**) and standing, is advised for ergonomic reasons, as poor postures exert uneven pressure on the spine, and the four natural curvatures of spine/backbone (i.e. cervical, thoracic, and lumbar spine) is preserved and maintained when lying, sitting, and standing. And may lead to uneven distribution of body weight. Therefore, efforts should be made to assume neutral postures, at all time; as this may be helpful in enhancing musculoskeletal health, and eventually help reduce the development of MSDs, like premature joint

*Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

#### **Figure 5.**

*(a) Three commonly assumed sitting postures a(i) – Ischio-femoral sitting posture, a(ii) – Sacra sitting posture, a(iii) – Sacro-femoral sitting posture [31]. b: Wrong b(i) and correct b(ii) office work-place sitting postures.*

degeneration, nerve pinching and/or back pain. When assuming "*neutral sitting posture*", it is important to always be careful in ensuring that, the:


These are the unnatural body positions (wrong postures) assumed at work (including poor manual handling), like bending, twisting, pocking of the neck - say, looking down at

#### **Figure 6.**

*(a) Illustration of proper lifting technique – a – starting position, b – bend your knees, keep your low back bowed-in, c – use correct grasp, d – use body weight to advantage, e – keep load close to the body [31]. (b) Some of the factors responsible for the development of MSDs.*

your monitor, extending one's wrists to type, overreaching - say, to operate the computer mouse, and wrong bending - during manual handling (**Figure 6**). These postures push the affected joints past the mid-range of motion, thereby exposing the joints to ergonomic hazards, and subsequent injuries. Properly optimized workstation will minimize awkward postures, and this essentially involve assumption of good posture while at work. For optimal workstation, the following adjustment may be required:


NB: When answering a phone call while at the work-station, the worker can use the speaker function instead of using the arm and/or shoulder wrongly, while holding up the phone.

#### *5.1.3 Prolonged stationary position*

This is prevalence among workers whose job tasks encourage sedentary lifestyle. Those who stay in the same position, for longer period of time. Usually sitting or standing in the same position for more than one hour is regarded as prolonged position [32]. Thus, prolonged stationary position is an ergonomic hazard; and it is advisable to observe regular breaks; of between 30 seconds to 5 minutes, usually every one hour, for stretching exercises at the work-place (**Figure 7**).

#### *5.1.4 Frequent repetitive movements*

Certain tasks require frequent repetitive movement. At the office space, the most common repetitive movements are performed by the fingers, wrist and arm. This can be observed in task involving the use of (operating) a mouse. The worker get to perform hundreds of small wind-shield movements with the wrist. This can be made worse, when the task is carried in an awkward position**,** and over a prolonged period of time. Performing repetitive motions repeatedly, however small, can cause microtrauma to the surrounding tendons and tissues, consequently leading to the development of MSDs. Observing regular rest (particularly of the affected part); of between 30 seconds to 5 minutes, usually every one hour, for stretching exercises, in addition to eliminating the awkward posture is imperative. This allows the body to heal itself, making the worker to recover when the fatigue overturns workers body's recovery system. And will subsequently leads to the reduction in the development of MSDs.

#### *5.1.5 Poor lighting at work*

Insufficient lighting, unwanted dark spots and shadows, glare, and improper color temperature are some of the most common examples of poor lighting at work. They can negatively impact your vision, mood, and even productivity. It is important for workplace lighting to conform to good lighting ergonomics. Ensuring good lighting ergonomics includes the following:

i.The office should be arranged for natural light as much as possible.

#### **Figure 7.**

*Therapeutic exercises at the workplace. (Each exercise is held or carried out for ten seconds, and repeated three times - for a complete bout of exercises).*


#### **6. Manual material handling (MMH), including patient handling**

Manual material handling (MMH) is the process of routinely moving and handling of objects (including patients) through a series of biomechanical functions, such as; carrying, holding, lifting, pulling, pushing, and stooping on a regular basis. According to Manual Handling Operations Regulations (MHOR), MMH involve "any activity requiring the use of force exerted by a person to lift, push, pull, carry or otherwise move, hold or restrain an animate or inanimate object" [33]. By this definition, MMH does not excessively involve material handling only, it is also an integral to the practice of the physiotherapy, and rehabilitation professional generally, particularly in patient handling [33]. This is because the work-task of rehabilitation professionals (including physiotherapists) often requires the performance of physically demanding therapeutic activities, refers to as, patient handling tasks (PHT), that may constitute risk of developing MSDs. Patient handling tasks in rehabilitation are usually classified as "traditional" or "therapeutic:" Traditional PHT have a practical goal, like transferring a patient from bed to a wheelchair; "therapeutic" PHT, on the other hand, have more targeted goals, like facilitating patient function and independence. By and large, PHT have been widely reported to be capable of exposing rehabilitation professionals to high mechanical loads, particularly, on the spine [33–35].

Generally, manual handling frequently involve the performance of unsupported static posture, (which are often awkward in nature), during the execution of any particular work-task, including PHT; which usually involve postures like bending, reaching forward, twisting, squatting etc. (**Figure 6**). During the assumption of these awkward postures, the workers and/or worker's body parts are positioned away from their neutral position (**Figures 6**, **8** and **9**). Work-place ergonomic control is therefore essentially required; and directed towards maintaining a neutral body position, and to keep arms and legs as close to the trunk as possible (**Figures 8** and **9**). Also, modern patient handling technology is often recommended as part of a comprehensive safe patient handling programme in therapeutic and rehabilitation settings, in addition to the implementation of a standard and effective WEP [33, 36].

**Figure 8.** *Common awkward shoulder (Flexion/Extension, Abduction/Abduction/Extension) from neutral.*

#### **Figure 9.**

*Common awkward repetitive motions of the wrist (Radial/Ulnar deviation & Flexion/Extension, from the neutral).*

#### **6.1 Principles of safe manual handling**

Basically, manual handling includes both transporting a load, and supporting a load in a static posture. The load may be moved or supported by the hands or any other part of the body, for example the shoulder. This may constitute ergonomic risks, particularly, if hazardous manual handling techniques are employed in the execution of the task (manual material and patient handling). In order to avoid work-place injury from hazardous manual handling, manual handling operations regulations require employers to:

a.*Avoid* hazardous manual handling, as much as possible;


Furthermore, the risk of developing MSDs sequel to manual handling (materials and patients) can also be reduced by avoiding or reducing assumption of awkward postures (i.e., twisting, stooping, stretching etc.). This can be achieved by changing the:


**Figure 10.** *Reduction of individual handling capability as the hands move away from the body [33].*

3.*Sequence of operations:* by improving the flow of materials or products. There is a reduction in the individual handling capability, as the hands move away from the body (**Figure 10**).

It is imperative to note that the provision of a safe/good handling technique is no substitute for other risk-reduction steps, such as providing lifting aids, or improvements to the task, load or working environment. Example, moving a load (including patient) by rocking, pivoting, rolling or sliding is preferable to lifting it in situations where there is limited scope for risk reduction [33]. The principles of safe manual handling involve effective assessment of the task, and effective planning of execution of task, including, proper positioning of the body for effective handling, thus, ensuring proper positioning of the feet, securing a proper grip, and keeping the load close to the body, use the

#### **Figure 11.**

*Lifting and lowering risk filter – Each box contains a filter value for lifting and lowering in that zone. The filter values are reduced if handling is done with arms extended, or at high or low levels, as that is where injuries are most likely to happen [33].*

leg muscles, with the view using body momentum to advantage (**Figures 10** and **11**). Assessment of manual handling risk is often anchored on four main areas, including the:


It is also important to access the weight of the load to be moved, and also to observe standard lifting technique (**Figure 10**). If it is less than the value given in the matching box, the operation is within the guidelines (**Figure 11**). If the lifter's hands enter more than one zone during the operation, use the smallest weight. If either the start or end positions of the hands are close to a boundary between two boxes you should use the average of the weights for the two boxes. According to [33]. The filter for lifting and

#### *Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

lowering assumes: (a) the load is easy to grasp with both hands, (b) the operation takes place in reasonable working conditions, (c). the handler is in a stable body position.

NB: A good handling technique forms a very valuable addition to other riskcontrol measures. To be successful, good handling technique needs both training and practice. This may be helpful in reducing the risk of injury. The effects of these factors are interrelated, and may partly depend on the nature and circumstances of the manual handling operations. If the manual handling operations are carried out in circumstances which do not really change, like in manufacturing processes; the emphasis is particularly on improving the task and working environment. However, if the manual handling operations are carried out in circumstances which change continually, like certain activities carried out on construction sites, in delivery jobs, or in manual patient handling; the handler may offer less scope for improvement of the working environment and perhaps the task. Here, more attention is directed to the load - for example making the Load lighter for easier handling.

Some of the common workplace risk factors (i.e., ergonomic hazard) in Office work-place, are also considered in manual handling work-space, however, there are workplace ergonomics risk factors that are specifically of great consideration in MMH work-space. These include poor lifting techniques (material handling), wrong worksitting, mix-match work-environment, and force/mechanical compression/vibration etc. (**Figures 5a, b** and **6a, b**)

#### **7. Discussion and conclusion**

This book chapter has provided a comprehensive description of Musculoskeletal system, the disorders of Musculoskeletal systems, causes and preventive strategies, using standard ergonomic principles, applicable at both materials manual handling work-place, and during patients management/rehabilitation. Ergonomic risk factors were discussed under two major categories, namely work-related (ergonomic) risk factors and individualrelated risk factors. Work-related (ergonomic) risk factors were further discussed under two sub-categories - Primary and secondary risk factors. The primary work-related (ergonomic) risk factors are basically physical in nature, and they included Sudden/ Forceful Exertions, High (Task) Repetitions, Awkward postures (Repetitive or Sustained), body vibration. The secondary risk factors include psychosocial factors (like work-pace, autonomy, monotony, work/rest cycle, task demands, social support from colleagues and management and job uncertainty). Other secondary risk factors include: Static Posture, Contact Stress, Cold/heat, Vibration, Noise, Physical Stress, Emotional Stress.

In order to evaluate the possibility of an employee developing WMSD, it is important to include all the relevant activities performed both at work and during leisure time activities (outside work). This is because, most of the WMSD risk factors can occur both at work and during leisure time activities. Also, because these ergonomic risk factors interact and act simultaneously, and has a synergistic effect on the musculoskeletal system, it is advisable and important to take into account this interaction rather than focus on a single risk factor.

#### **Objectives**

After studying this chapter readers should be able to:

• Describe the mechanism of the causes and prevention of WMSDs.


#### **Acknowledgements**

The writing of this book chapter was influenced by the experience gathered from the teaching, particularly, of my Postgraduate students, at the department of Physiotherapy, college of Medicine, of the University of Lagos. Which started in 2009, when the Postgraduate Physiotherapy programme of the University of Lagos started. The author also appreciate Mr. Bamidele O. Olabisi of Biomedical Communication of College of Medicine, University of Lagos, Lagos, Nigeria, for the drawing of the illustrations

### **Conflict of interest**

The author declare that this book chapter was written in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

#### **Notes/thanks/other declarations**

N/A

*Musculoskeletal Disorders, Workplace Ergonomics and Injury Prevention DOI: http://dx.doi.org/10.5772/intechopen.106031*

#### **Author details**

Daniel O. Odebiyi1 \* and Udoka Arinze Chris Okafor2

1 Faculty of Clinical Sciences, Department of Physiotherapy, College of Medicine, University of Lagos, Lagos, Nigeria

2 Department of Physiotherapy, College of Medicine, University of Lagos, Lagos, Nigeria

\*Address all correspondence to: femiodebiyi@yahoo.com

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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#### **Chapter 3**

## Musculoskeletal Disorders in the Teaching Profession

*Patience Erick, Tshephang Tumoyagae and Tiny Masupe*

#### **Abstract**

Musculoskeletal disorders (MSDs) are among the most common and important occupational health problems in working populations with significant impact on quality of life and a major economic burden from compensation costs and lost income. MSDs decrease productivity at work due to absenteeism, presenteeism and sick leave. During the course of their work, teachers can be subjected to conditions that cause physical and psychosocial illness. Common MSDs among teachers include those affecting the lower back, neck and upper extremities. Research suggests that the aetiology of MSDs is complex and multifactorial in nature. Occupational factors including location of school, carrying heavy loads, prolonged computer use, awkward posture and psychosocial factors such as poor social work environment, high anxiety and low job satisfaction have been found to contribute to development of MSDs. Factors such as high supervisor support and regular physical exercise on the other hand have been found to have a protective effect against MSDs among teachers. The interventions for these conditions need to be contextualized for them to be effective and to take into consideration, the risk factors for these conditions and how they interact with each other.

**Keywords:** musculoskeletal disorders, low back pain, neck pain, lower limb pain, teachers

#### **1. Introduction**

Musculoskeletal disorders (MSDs) represent one of the most common and most costly occupational health problems globally [1]. Developing countries are disproportionately affected where working conditions could be poor due to acute lack of awareness on ergonomic issues, education and training [2]. MSDs have also been associated with high levels of health-related presenteeism, absenteeism and sick leave among teachers [3]. MSDs are conditions that affect the body's muscles, joints, tendons, ligaments, nerves, bones and their local blood supply. Most work-related MSDs develop over time and caused by either work itself or the worker's working environment [4].

School teachers, in general, have been shown to report a high prevalence of MSDs relative to other occupational groups [5], with prevalence rates of between 40% and 95% according to a systematic review conducted in 2011 [1]. These high prevalence rates among teachers are associated with individual, work-related and psychosocial factors. Some studies have investigated the relationship between MSDs in teachers and their working conditions. The work tasks of teachers involve a wide variety of duties and responsibilities that may involve prolonged sitting and standing, use of inappropriate furniture, awkward postures likely adopted when writing on the board, helping students with their work or when helping students during extracurricular sporting activities. Furthermore, teachers might adopt awkward postures when reading, marking students' work or preparing lessons. The constant loading of the muscles in the neck, shoulders and the back eventually leads to aches, pains or discomfort [5, 6]. In some instances these activities may be carried out under unfavorable working conditions. Psychosocial risk factors such as poor mental health, low supervisor or colleague support, low job satisfaction, high job stress and high psychological job demands have also been associated with development of MSDs [1]. Preventive programmes are required for management of these disorders and this should ideally be at organizational level rather than individual level [7].

#### **2. Assessment of MSDs among teachers**

Historically, evaluation of MSDs has involved use of many different methods ranging from broad approaches to specific techniques. Widely accepted approaches for determining the prevalence of MSD and favoured by researchers include self-developed questionnaires [8–10] and the Standardized Nordic Questionnaire [11–14]. Selfdeveloped questionnaires can be structured, semi-structured or unstructured [8] and employ open vs. closed, single vs. multiple responses, ranking, and rating [15, 16]. The Standardized Nordic questionnaire was developed by a Swiss company for analysis of musculoskeletal symptoms. It has both the General the Specific Questionnaire. The General Questionnaire is a graphic in which the human body is split into nine anatomical regions, whereas the Specific Questionnaire focuses on anatomical locations where musculoskeletal problems are more common [9]. The fundamental benefit of using these questionnaires is that they examine the severity of symptoms, their impact on work and leisure activities, the overall duration of symptoms, and sick leave.

Other MSDs evaluation methods include pilot study surveys and questionnaires like the pilot tested surveys, [17–19], questionnaires such as the Northwick Neck Pain Questionnaire [20], Health Questionnaires [21], Job Content questionnaires [22] and the Subjective Health Complaints Questionnaire [6]. While questionnaires are a costeffective and manageable method to collect data, they can create recall bias and make follow-up difficult, particularly when anonymous reporting is used [1]. Disregard of physical examination and assessment pervades diagnosis of MSD even though they could likely produce more accurate results. These methods are considered expensive and time consuming and therefore rarely used [1].

The majority of the research used self-reported questionnaires to assess MSDs. Self-reporting has limitations such as participants not being honest, introspective inability, wrong interpretation of questions, recall [23] and sampling bias. The participant recall bias could lead to under or overestimation of MSDs [24]. Additionally, self-reporting could lead to respondents reporting all pain as MSDs [25]. It is also not possible to establish any causal-effect associations through self-reporting [26]. The presence of MSDs is only dependent on the participants' self-reports and not on an objectively validated diagnosis.

#### **3. Prevalence of MSDs among teachers**

Following the systematic review on MSDs among school teachers that was done in 2011 by Erick and Smith [1], substantive research has been carried out on the subject. Globally studies have been conducted among nursery to secondary school teachers on MSDs generally and/or on specific body sites such as neck and/or shoulder, back, upper and/or lower limbs. Recently it was estimated that approximately 1.71 billion people globally have musculoskeletal conditions [27]. A previous systematic review of MSDs among school teachers which was based on papers published between 1981 and 2011 revealed that these conditions affect between 39% and 95% of teachers [1]. The prevalence rates of MSDs among school teachers reported on studies carried out after this review range between 21.1% and 96%.

#### **3.1 Global prevalence of MSDs among teachers**

#### *3.1.1 Prevalence of MSDs in Asia*

A substantive amount of research on MSDs among teachers has been conducted in the past ten years in Asia. The prevalence rates of general MSDs in the region range between 21.1% and 93.7% with high prevalence rates of 90.7–93.7% reported among school teachers in China [28]. Similarly, 87.3% and 80.1% of secondary school teachers in Saudi Arabia [23] and primary school teachers in Malaysia, respectively [29] reported ever experiencing MSDs. Furthermore, in a study carried out in Pakistan [30] and another study from Saudi Arabia [31], 82.7% and 79.2% female school teachers reported MSDs, respectively. Prevalence rates of MSDs ranging between 60.3% and 74.5% were reported among school teachers in other Asian countries [8, 32–35]. Low prevalence rates of MSDs have been reported among primary teachers in another study conducted in Malaysia (40.1%) [36] and male secondary teachers in Saudi Arabia [21].

#### *3.1.2 Prevalence of MSDs in South America*

Relatively few studies have been carried out to investigate the prevalence of MSDs among teachers South America. In Chile, the 12-months prevalence of MSDs among school teachers was 88.9% [26] while in Bolivia it was 86% [37]. A 7-days MSDs prevalence of 63% was reported among Bolivian school teachers [37]. In a study of chronic musculoskeletal pain among Brazilian teachers in Londrina, 43% reported experiencing chronic pain in the past 12 months [38].

#### *3.1.3 Prevalence of MSDs in Africa*

A high prevalence rate of MSDs was reported among Egyptian nursery school teachers (96%) [39]. In Botswana, a 12-months prevalence of MSDs among primary and secondary school teachers was 83.3% [40]. The prevalence rates of MSDs among teachers in two studies carried out in Ogun State [10] and Enugu State, Nigeria [41] were 70.47% and 70.2% [41], respectively.

As reflected above, MSDs appear to be highly prevalent in the teaching profession with the high prevalence reported among nursery schools. MSDs studies carried out in Europe were specific to different body sites.

#### **3.2 Prevalence of MSDs according to different body sites**

#### *3.2.1 Neck and/or shoulder pain*

Although most of the studies investigated 'neck pain' and 'shoulder pain' separately, some combined these and reported on them as neck and/or shoulder pain (NSP). In a study conducted in Durban, South Africa a 12-months prevalence of NSP among primary school teachers was 80.4% [42], In Chile, 68.6% of school teachers reported NSP in the last 12 months [26]. Similarly, in two separate studies conducted in Malaysia, 60.1% of secondary [43] and 56.5% of primary [29] school teachers reported NSP. Parallels could be drawn to a study conducted in Ethiopia where 57.3% of teachers reported NSP [13]. In a study conducted in China, almost half (48.7%) of school teachers reported experiencing NSP in the previous 12 months [44]. These studies show that MSDs of the neck/shoulder are highly prevalent.

#### *3.2.2 Neck pain*

Even when neck pain is reported separately, there is still evidence that it is a prevalent MSD among school teachers with studies from different countries reporting prevalence rates above 50% with high levels reported in Turin, Italy at 75.6% [45]; followed by Nigeria at 57% [41, 46], Botswana at 50.2% [40] and Bolivia at 47% [37]. Other countries however reported low prevalence rates of neck pain among teachers. Low prevalence of neck pain have been reported among Saudi female teachers (11.3%) [47] and Nigerian teachers (3.2%) [10].

#### *3.2.3 Shoulder pain*

High prevalence rates of shoulder pain were reported by teachers in China (73.4%) [44]. Parallels could be drawn to the results of a study that was conducted in Nigeria where 62.3% of teachers reported shoulder pain. Most of the studies reported prevalence rates ranging between 41% and 57.5% [12, 21, 23, 30, 32–34, 46, 48, 49]. However, low prevalence rates were reported in studies conducted among female teachers in Malaysia (22.2%) [36] and Saudi Arabia (20.6%) [47] and primary school teachers in Egypt (15%) [50] and Ogun State, Nigeria (11.7%) [10]. Lessons could be learnt from these places on factors associated with these low rates of shoulder pain.

#### *3.2.4 MSDs in the upper extremities*

When compared to other MSDs, upper extremities appear to be less prevalent. A study that was conducted in Brazil reported that 14% of teachers experienced upper limb pain [38]. Wrist/hand pain was reported by 26% teachers in Chuquisaca, Bolivia [37], 23.4% in Turkey [51] and 16.2% secondary female teachers in Saudi Arabia over 6 months [31] and 7.4% in another study conducted among female teachers in Saudi Arabia over 3 months [47]. Elbow pain on the other hand was reported by between 5.6% and 16% of teachers in studies carried out in Italy [45], Turkey [51], and Malaysia [36]. Although prevalence rates for MSDs of the upper extremities were generally low across most countries, there were a few countries where prevalence rates could go above 40% as was the case among primary school teachers in Kota Kinabalu, Malaysia who reported hand/fingers pain in the last 6 months [29].

*Musculoskeletal Disorders in the Teaching Profession DOI: http://dx.doi.org/10.5772/intechopen.103916*

#### *3.2.5 Low back pain*

In this section, the prevalence of back pain among school teachers is discussed. Limited studies reported general back pain whilst majority separated low back pain and upper back pain. The prevalence of general back pain was reported in studies conducted in Qassim, Saudi Arabia (74.4%) [11], Minas Gerais, Brazil (58%) [52], Turkey (42.7%) [34] and Iran (39%) [12].

When compared to other MSDs among school teachers, low back pain (LBP) appears to have been the most studied. High prevalence rates of low back pain have been reported in studies conducted in Spain [53], Jordan [54] and Ekpoma State, Nigeria [46] where 96.5%, 92.3% and 85% school teachers reported low back pain respectively. Almost three-quarters of teachers in Turkey (74.9%) [34], Northern Ethiopia (74.8%) [55], Putrajaya Malaysia (72.9%) [9] and Italy (70.6%) [45] reported experiencing LBP in the past 12 months. Most of the studies reported prevalence rates between 35.3% and 68% [14, 23, 24, 31, 32, 42, 47, 56, 57]. However, some studies reported low prevalence rates. One quarter of female teachers in Terengganu, Malaysia [36] and school teachers in Kanpur, India [58] reported LBP in the previous 12 months. In Abha City, Saudi Arabia [21] and Ogun State, Nigeria [10], one fifth of teachers reported LBP while in Brazil 13% of them also reported LBP [38]. LBP is common among teachers regardless of the geographical location. This is a concern as LBP is a leading cause of disability in both developing and developed countries [44].

#### *3.2.6 Upper back pain*

Upper back pain does not appear to have been studied as much as LBP. Although 84% of preschool teachers in Turin, Italy reported experiencing upper back pain [45] it appears this pain is not as prevalent as LBP. This is evidenced by prevalence rates reported in studies carried out in Enugu State in Nigeria [41], Peshawar, Pakistan [30] and Thailand [33] where 47.4%, 43.3% and 36.1% of school teachers reported upper back pain, respectively. In Terngganu, Malaysia, one quarter of female primary school teachers reported upper back pain experienced in the previous 12 months [36]. Lower prevalence rates were reported among female Saudi teacher (17.7%) [47] and teachers in Ogun State in Nigeria (1.1%) [10].

#### *3.2.7 MSDs of the lower extremities*

Several studies have investigated MSD in the lower extremities such as the knees, leg, hips, ankles and feet. In a study conducted in Kota Kinabalu, Malaysia, almost half of the primary school teachers reported lower extremities pain in a period of 6 month [29]. However, a lower prevalence of 13% was reported in a study of Brazilian teachers [38]. The prevalence rates of knee pain among different school levels ranged between 26.3% and 49%. About 49% of nursery school teachers in Ekpoma State in Nigeria reported knee pain [46] while it was reported by 41% of secondary school teachers in Hail, Saudi Arabia [23]. Parallels could be drawn to the results of studies conducted in Enugu State of Nigeria [41] and Turin, Italy [45] where 39.3% and 38.7% of teachers and nursery school teachers reported knee pain respectively. One third of teachers in Turkey [34] and Terengganu, Malaysia [36] reported knee pain in the last 12 months while in Saudi Arabia one quarter reported the same condition in the past 3 months [47].

The prevalence rates of leg pain among teachers ranged between 38.7% and 65.2%. The highest prevalence rate was reported by school teachers in Ogun State in Nigeria [10] while the lowest was reported by preschool teachers in Turin, Italy [45]. Hip pain was reported by between 15.4% and 45.3% of teachers in Enugu State in Nigeria [41], nursery schools in Ekpoma State in Nigeria [46], female teachers in Saudi Arabia [47] and teachers in Turkey [34]. Some studies combined hip and thigh pain and was reported by 49.6% preschool teachers in Italy [45] and 18.4% of teachers in Terenggamu, Malaysia [36] in the past 12 months.

The prevalence of ankle pain was relatively common among teachers ranging between 12.3% and 48.4%. Female teachers in Pakistan reported the highest prevalence rate of this pain (48.4%) [30]. Although nursery school teachers have been thought to be at increased risk of ankle pain due to activities which require sustained periods of kneeling, stooping, squatting or bending [59], only 31% of nursery school teachers in Ekpoma State, Nigeria reported ankle pain [46]. Some studies studied ankle and feet pain combined and the highest prevalence (85.5%) was reported in a study conducted among school teachers in Abha City, Saudi Arabia [60]. However, relatively low prevalence was reported in studies carried out in Terenggamu, Malaysia [36] and preschool teachers in Italy [45] where this pain was reported by 32.5% and 16.8% of the study population, respectively.

MSDs have been previously reported to be more prevalent among nursery school teachers because of the kind of work they do. This chapter confirms the previous findings because when compared to other school teachers, high numbers of nursery teachers reported general MSDs, upper back pain, neck and/or shoulder, knee and elbow pain. This has been attributed to that nursery school teachers perform a wide variety of tasks and combine basic health childcare and teaching duties, and those that require sustained mechanical load and constant trunk flexion [59, 61]. Furthermore, nursery school teachers have been found to have elevated prevalence of MSDs due to activities which require sustained periods of kneeling, stooping, squatting or bending [59]. The high prevalence of MSDs of different body sites among teachers is a concern as this population consists of high numbers of members of the society. Teachers ill-health does not only affect them but high likely to affect learners. Therefore, it is crucial to establish work-related factors that affect this population to put in place control measures that will reduce prevalence and progression of these conditions. The following section discusses work-related factors associated with teachers reporting MSDs.

#### **4. Work-related risk factors for MSDs among teachers**

A large proportion of MSDs have been associated with adverse work conditions. Increased risk of these disorders have been reported in occupations with repetitive work tasks, awkward postures and heavy lifting as well as psychologically demand work environments. The section will discuss work-related factors associated with MSDs among school teachers.

#### **4.1 Location of school**

In a study carried out in both rural and urban areas of Bolivia, teachers working in rural areas were more than two to almost four times more likely to report any work limiting musculoskeletal pain during the last 12-months and for work limiting pain

*Musculoskeletal Disorders in the Teaching Profession DOI: http://dx.doi.org/10.5772/intechopen.103916*

in at least three parts of the body than teachers in urban areas. The study also found that work limiting pain in ankles was higher in rural than urban school teachers [37]. These findings have been attributed to that apart from the teaching responsibilities, teachers in rural areas work closely with the rural communities which could be both physically and psychologically demanding. For this reasons, there is often concentration of professionals in urban areas as opposed to rural areas which in turn impacts on the quality of education and increased inequalities between the two areas [37].

#### **4.2 Carrying heavy loads**

Carrying heavy loads have also been associated with MSDs among school teachers. Brazilian teachers in Londriana region who reported carrying didactic materials were almost two times more likely to report upper limbs pain than those who did not report carrying heavy materials [38]. Lifting loads with hands was also associated with LBP among secondary school teachers in Putrajaya, Malaysia. Teachers who reported lifting loads with hands were at increased risk of developing LBP than those who did not report so [9]. Carrying weight has also been significantly associated with MSDs among secondary school teachers in Fiji [62].

#### **4.3 Prolonged computer use**

Prolonged computer use has previously been associated with MSDs of different body sites among school teachers. Brazilian teachers in Minas Gerais region who reported using computer or tablet within 5 h and for 6 or more hours during the COVID -19 pandemic were 1.12 times and 1.27 times more likely to report back pain compared to those who did not report computer or tablet use [52]. Primary school teachers in Samsun Turkey who reported daily computer use were at increased risk of neck pain when compared to those who did not indicate daily computer use [34]. Prolonged computer use leads to prolonged sitting. Activities of prolonged sitting and computer use are unsafe acts favorable for the development of neck/shoulder pain, back pain and upper limb pain among teachers [44]. This may also be attributed to a sustained forward head posture and/or constant neck flexion which cause static overload of neck and shoulders muscles. When combined with repetitive movements associated with a mouse, touchpad or keyboard can increase the likelihood of shoulder and/or neck pain [48].

#### **4.4 Awkward postures**

Awkward postures have been found to contribute to reporting of MSDs. This is evidenced by the results of a study among primary school teachers in Cairo, Egypt where awkward posture was associated with MSDs [50]. Furthermore, teachers who reported awkward arm position at work in a study conducted in Botswana were 1.4 times more likely to report LBP than those who did not report awkward arm position [63]. In another study conducted in Botswana, teachers who had reported awkward arm position when working were at risk of shoulder pain, upper back pain and wrists/ hands pain [40]. Teachers in Gondar town of Ethiopia who had reported static head down posture and elevated arm over shoulder were 2.26 times and 2.71 more likely to report shoulder/neck pain than those who did not report the awkward postures [13]. Similarly, Chinese teachers who reported prolonged static posture were more likely to develop NSP and LBP than those who did not report static posture. Teachers who

reported that they acquired posture characterized by twisting were also at increased risk of LBP than those who did not report so [44]. Bending has been significantly associated with MSDs among secondary school teachers in Fiji [62].

Stretching to write on the board placed school teachers in Thailand at increased risk of repetitive strain injuries [33]. Writing on the board has also been strongly associated with MSDs of different anatomical areas such as upper limbs pain, LBP and lower limbs pain among Brazilian teachers in Londrina region [38]. Forward-bending and backward bending of the head for a prolonged time when writing on the board has been significantly associated with NSP among primary school teachers in South Africa [42]. Shoulder pain may occur as a result of working with raised arms unsupported for a considerable time, a characteristic synonymous with teachers' work as they write on the board. Awkward postures caused by sustained muscle stretching particularly overhead are likely to induce neck and/or upper limbs pain in teachers. Awkward postures affect MSDs of different body areas. This is so because the broad activities which teachers participate in such as reading, marking, lesson preparation lead to prolonged sitting periods, bending to assist students at student level, writing on and reading from the board put strain on different body areas.

Prolonged sitting and standing have been associated with MSDs of different body area. A study of Chinese teachers in Guang dong Province, found that those who reported prolonged sitting were at risk of reporting NSP and LBP than those who did not report prolonged sitting. NSP was also experienced by those teachers who reported prolonged standing than those who did not [44]. Prolonged standing has also been associated with LBP among Egyptian teachers [55] and general MSDs among male secondary school teachers in Saudi Arabia [32]. Prolonged sitting has also been significantly associated with NSP among Gondar teachers in Ethiopia [13], with LBP among secondary school teachers in Putrajaya, Malaysia [9] and among primary school teachers in Durban, South Africa [42] and foot pain among Saudi teachers in Abha Sector [60]. Prolonged standing and sitting were also significantly associated with MSDs among female school teachers in Pakistan [30] and secondary school teachers in Fiji [62]. Standing and sitting for a long period, working in a head down posture for long periods, bending/twisting upper body have been significantly associated with MSDs among preparatory government school teachers in Cairo, Egypt. The study further found that prolonged working in the same posture, helping students into flexing posture and repeating the same movement of arms or hands many times per minute were also significantly associated with MSDs [39].

#### **4.5 Inappropriate furniture**

Previous research indicates that inappropriate furniture contributes to development of MSDs. A significant association has been found between MSDs and school furniture among school teachers in two separate studies carried out in Egypt [39, 50]. Uncomfortable work chair/table was significantly associated with MSDs among female school teachers in Pakistan [30]. In China, school teachers who reported uncomfortable back support were about two times more likely to report NSP and LBP compared to those who did not report so [44]. Women teachers, nurses and sonographers in Sweden who reported that they were dissatisfied with computer workstation arrangements were 1.2 times more likely to report neck pain and shoulder pain respectively than those who reported that they were satisfied [64].

Similarly, school teachers in Enugu State of Nigeria who reported using teaching board with height of 180–190 cm and more than 190 cm were 3.5 times and 4.6 times more likely to report neck pain, respectively than those who used teaching board that was less than 180 cm. Furthermore, those who reported using a teaching board with height of 180–190 were also at increased risk of pain in one or both elbows [41]. These heights may lead to adoption of prolonged neck extension positions when writing on or reading from the board and ultimately contribute to neck pain.

#### **4.6 Workload**

Although it is assumed that physically school teachers' work is varied and relatively light [64], research on this study population has demonstrated that they are exposed to high workloads. Rapid physical activity has been significantly associated with shoulder pain, wrists/hands pain and hips/thighs pain among school teachers in Botswana [40]. Similarly, primary school teachers in Samsun, Turkey who reported physical activity were two times at risk of neck pain when compared to those who did not report physical activity [34]. Walking up and down stairs was associated with LBP among secondary school teachers in Putrajaya, Malaysia [9].

High workload has been significantly associate with MSDs among preparatory teachers in Egypt [39]. Addis Ababa teachers who reported high work load were four times increased risk of reporting LBP than those who were not [14]. This is consistent with results of primary school teachers in Egypt where job demand was significantly associated with MSDs [50]. Physical workload has also been associated with feet pain among women teachers, nurses and sonographers in Sweden [64]. In Londrina, Brazil, high number of students in a classroom were associated with upper limbs pain [38].

The association between high job demand and MSDs might be due to the nature of teachers' work which by its nature is physically demanding. When the physical work load is reduced, the impact of job demand and onset of MSDs is reduced [65]. Apart from teaching students, teachers are also involved in lesson preparation, assessments of students' work and being involved in the extracurricular activities such as sports. Teachers also participate in different school committees. These may cause teachers to suffer adverse mental and physical health issues due to the variety of job functions [1].

#### **4.7 Psychosocial factors**

School teachers are considered to experience high level of psychological stress [64]. High psychological job demands have been associated with LBP [63], upper back pain and shoulder pain among school teachers in Botswana [40]. Similar results have been reported among secondary school teachers in Malaysia where those who reported high psychological job demands were at increased risk of developing LBP compared to those who reported low psychological job demands [43]. Psychological job demands have been associated with neck, shoulder, hands, lower back and feet pain among women teachers, nurses and sonographers in Sweden [64]. It has been suggested that the more psychological demands needed for a particular task, the greater the possibility to develop any kind of MSDs regardless of the body area [66].

The study of teachers working in governmental primary schools in Addis Ababa, Ethiopia found that those who reported a poor or fair work social environment were at increased risk of LBP than those who had good work environment [14]. Similarly teachers in another study conducted in Gondar town in Ethiopia, who reported to have stress were more likely to report LBP than those who did not report stress [57].

Mild to moderate and severe to extremely severe stress have been associated with experiencing LBP and NSP among secondary school teachers in Malaysia [43].

High anxiety and very low colleague support have been associated with MSDs among preparatory teachers in Egypt [39]. Parallels could be drawn to results of Malaysia secondary school teachers who were found to be at increased risk of LBP and NSP due to mild to moderate and severe to extremely severe anxiety [43].

Teachers in Tehran, Iran who reported low job satisfaction were more likely to develop low back when compared to those who reported high job satisfaction [56].

Low skill discretion and low supervisor support have been significantly associated with reporting low back and neck and/or shoulder pain among Malay teachers, respectively [43].

#### **5. Protective factors**

Some factors have shown a protective effect against MSDs among school teachers. These include factors such as workplace support, regular physical exercise and perceived better health.

#### **5.1 Workplace support**

A protective effect was demonstrated for Botswana teachers who reported high supervisor support. These teachers were less likely to report neck, upper back pain and hip/thigh pain as compared to those who reported low supervisor support [40]. High supervisor support was also a protective factor against LBP among Kenyan teachers [24]. Ethiopian teachers in Amhara region who reported satisfaction with work environment and culture were showed decreased odds for reporting LBP and those who had an office were also less likely to report LBP [57].

Nursery and primary school teachers who reported that there were three of them per class were less likely to report upper back, low back pain and pain on one or both ankles or feet [41].

In a study carried out among women teachers, nurses and sonographers, those who reported high job control were less likely to report shoulder, hands, lower back and feet pain. The study further demonstrated that those in leadership were less likely to report neck, shoulder and lower back pain [64].

#### **5.2 Regular physical exercise**

Physical exercise of more than 5 h per week was associated with reduced odds of reporting upper back pain [40] and LBP [63] among school teachers in Botswana. This was in comparison to teachers who reported five or less hours of weekly exercise. Similarly, teachers in Amhara region in Ethiopia who exercised were less likely to report LBP compared to those who did not exercise [57]. Chinese school teachers who reported exercising for seven or more hours per week were less likely to experience NSP compared to who exercise for less than 7 h per week [44]. Parallels could also be drawn to the results of a study conducted among Ethiopian teachers where those who exercised reported decreased odd of NSP compared to those who did not exercise [13]. Physical exercise was also associated with decreased odds of reporting neck pain among Iranian teachers [67], and upper back pain and LBP among school teachers in Enugu State, Nigeria [41]. Exercise habits also had a protective effect against neck

and upper extremity pain among teachers in Turkey [51]. Saudi teachers who reported that they were involved in sports were less likely to report foot pain [60].

#### **5.3 Perceived better health**

Teachers who were generally healthy in a study conducted in Iran, were found to be less likely to experience neck pain [67]. Better self-perceived mental health reported by Malay teachers demonstrated a protective effect against LBP and NSP [43].

#### **6. Management of MSDs**

As reflected above, MSDs are common among teachers with different contributing factors. This means that management of these need to evaluate risk factors for MSDs carefully before coming up with interventions to address them. The interventions for disorders need to be contextualized for them to be effective and to take into consideration, the risk factors for these conditions and how they interact with each other. MSDs disproportionately affect females compared to their male counterparts among school teachers in Saudi Arabia [23]. Aging and improper postures have also contributed to experience of MSDs among teachers in Punjab [68].

#### **6.1 Workplace preventative programmes**

Preventive programmes are required for management of these disorders and this should ideally be at organizational level rather than individual level [7] and also use health promotion approaches to them prevent repetitive strain injury (RSI) [33]. Previous research speak to prevention measures to reduce back pain [24]. In a study conducted among Chinese teachers, there was a statistically significant improvement in attitudes, awareness, symptoms on neck and back pain after 6 and 12 months post intervention. Researchers had administered a multi-faceted workplace intervention comprising of health education through lectures, workplace ergonomic training and public awareness materials using posters and brochures and assessed pre and post intervention effects of the workplace programme [28]. Similar findings were reported among nursery school teachers who underwent an Extension oriented exercise programme to prevent LBP in nursery school teachers. The programme was found to alleviate LBP among teachers who received brochure and exercise programme done by a physiotherapist compared to those who received only the brochure [33]. Preventive interventions focusing on posture have also been shown to work including reducing amount of time on awkward postures such as knee bending among pre-school teachers in Germany [69].

#### **6.2 Individual coping strategies**

Individual coping strategies are an important consideration for managing MSDs among teachers. This is because teachers may engage or prefer certain self-help therapies which may not necessarily be effective in prevention and management of MSDs as reported in one study where teachers used thermal spring therapy and/or painkillers to cope with their MSD pain [70]. Coping mechanism used by people suffering from MSDs can be influenced by gender and social class. This has been shown in one study where men in lower social class were found to prefer avoidant coping mechanisms compared to female counterparts while females in low social class used less problem solving methods to cope with MSDs [71]. Maintaining regular physical activity both at work and at home has demonstrated benefits for physical education teachers in terms of experiencing MSDs and their overall health and wellbeing especially their cardiovascular health [72] indicating a need to approach management of MSDs using a comprehensive risk based approach.

#### **6.3 A comprehensive model of MSDs at work**

The importance of a comprehensive multi-faceted programme to tackle MSDs is underlined by findings from a systematic review which demonstrated that massage therapy alone, a common mode of treatment for MSDs had limited benefits among patients with neck and back pain and no statistically significant benefits when compared to other treatments [73]. Additionally, patients diagnosed with MSDs commonly have other medical conditions including mental health and gastrointestinal conditions with those patients more likely to report a severe form of MSDs [74]. These patients may benefit from a holistic approach to the MSDs. A model of managing MSDs therefore requires further exploration and consideration. This is the bio-psychosocial (BPS) model of pain management.

#### *6.3.1 The bio-psychosocial model*

The model consists of three factors operating in the patient's life which are the environment, biological and cognitive factors [75]. The model posts that biomedical approaches alone have not been effective in managing pain especially MSDs and therefore a more holistic approach consisting of managing the patient biological factors, their environment and the way they think about pain, cognitive factors is key.

The model brings together an appreciation of how the risk factors already alluded to can all be incorporated effectively in a workplace programme for prevention and management of MSDs. The risk factors can seem to be too many and overwhelming to tackle for both patient and healthcare providers. However by designing a programme consisting of biological risk factors relating to the person and disease itself, cognitive factors and the environment in which illness occurs. The BPS model emphasizes the importance of making health within the patients' context taking into consideration the patients' sociocultural beliefs about illness, worries and concerns they may have about the meaning of the illness for their job and them as a person and possible coping mechanism that they have which may enhance or detract from effective interventions. Likely benefits of the bio-psychosocial model are echoed by Waddell who estimates that incapacity and sickness absence from these disorders could be reduced by up to 50% [76] and expounds on the key components of the BPS model of disability.

#### **7. The impacts of MSDs on teachers**

An important question to consider is why the public, the employers and employees must be concerned about effective prevention and management of MSDs in general and more importantly among teachers. There are bound to be costs encountered by the employee, the employer and the public because of the employees' inability to perform their duties effectively. The costs can be both tangible and intangible, direct

and indirect. Assessing the impact of MSDs must therefore take a 360° view of who is affected and how are they affected. The impact can be felt at individual level and societal level.

#### **7.1 Individual level impact**

MSDs present with symptoms of pain, fatigue and functional limitations [71]. They have also been shown to adversely affect the physical and emotional components of quality of life and a likely cause of future ill health and disability [26]. Work performance is another impact of MSDs shown to affect academic teachers due to lack of adequate mental and physical rest from work even while at home [77]. A study among teachers in Botswana also noted that the effect of MSDs included functional limitations and at times career change with important implications for limited resources [40]. Increased sick leave among female teachers as well as rising levels of depression were found to be associated with having MSDs in Turkey [70]. It is clear that with symptoms experienced from these disorders, individual teachers are likely to experience functional limitations at home and at work.

#### **7.2 Economic impact**

Treatment of MSDs in general has been shown to provide economic benefits in terms of keeping people employed and earning an income in addition to reducing sickness absence from work. A study done among adults with MSDs in the UK, where 54% were employed, it showed that an average of 3.8 days were lost due to work absenteeism. The study further found that reduced functional limitations led to a reduction in the patients' ability to remain in employment, higher chances of claiming disability benefits and sickness absence [78], which all add to the economic costs of MSDs. Patients experiencing MSDs in another UK study reported that their MSDs contributed significantly to their inability to work (74%) with a quarter reporting inability to find a suitable job because of the MSDs, low job satisfaction (68%) and half experiencing limited career choices and similar proportion experiencing reduced household income [74]. These were however not all teachers but it is likely that even teachers would experience similar challenges given the physical and psychological demands of their role as teachers and the nature of MSDs. These economic cost of MSDs has long been established. Canada reported an estimated economic cost due to MSDs as early as two decades ago at 26 billion Canadian dollars with the bulk of the costs being due to healthcare resource utilization and disease sequelae [79].

#### **7.3 Societal level impact**

The impact of MSDs among teachers on other aspects of the society are not well studied. For example, the impact on the pass rates of their students, career choices of their students and psychological wellbeing of the students. It is expected that students will experience some anxiety related to sickness absence of their teacher or having a temporary teacher to replace their substantive teacher. It is also possible that the temporary teacher may not have the same qualifications and experience as the substantive teacher, they may also not have the organizational context or institutional memory which would help them to navigate the school environment and the so called difficult students effectively. This is an important area of future research.

### **8. Conclusion**

Although self-administered questionnaires have recall biasness, introspective inability and may be subject to wrong interpretation of questions, they have been commonly used to investigate MSDs. This chapter demonstrated that MSDs are common among teachers despite of their geographical location. Additionally, MSDs are a cause of pain and suffering for teachers globally. Some countries have higher than average prevalence rates for all MSDs. Physical and psychosocial risk factors have been associated with MSDs of different body regions. Factors such as high supervisor support, high job control and regular physical exercise have been shown to have a protective effect against MSDs. Due to the effects of MSDs on individual life, work attendance and productivity it is important to manage these. Because MSDs tend to affect more than one body site and are mediated by multiple factors, a workplace approach to managing these should be holistic and as comprehensive as reasonably practicable. Future research using longitudinal study designs should be conducted to establish the casual effect of work-related and psychosocial factors in development of MSDs. Research is also needed to identify innovations that can reduce the prevalence of these disorders.

### **Conflict of interest**

The authors declare no conflict of interest.

### **Author details**

Patience Erick1 \*, Tshephang Tumoyagae1 and Tiny Masupe2

1 Department of Environmental Health, University of Botswana, Gaborone, Botswana

2 Department of Family Medicine and Public Health, University of Botswana, Gaborone, Botswana

\*Address all correspondence to: erickp@ub.ac.bw

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Musculoskeletal Disorders in the Teaching Profession DOI: http://dx.doi.org/10.5772/intechopen.103916*

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**Chapter 4**
