Department of SPM – Public Health@UM: Creating the future of Public Health
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Getting it Right – Ergonomics in the Workplace

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The majority of people who have heard of ergonomics assume it has to do with sitting or with the layout of automotive controls and instrumentation, but it actually encompasses much more. Anything that involves humans, including public transportation, buildings, living quarters, workplaces, products, and systems, can be designed or set up according to ergonomic principles to make it more user-friendly.

To ensure that we are as comfortable as possible at work, ergonomics is crucial. This indicates that we are employing the proper tools and equipment and that our workspace is ergonomic and comfortable.

There are a few things that we can do to make sure that we are getting it right:

1. Reduce Excessive Force

There is no one-size-fits-all answer to reducing excessive force in the workplace, as the best way to reduce the use of force depends on the individual and their specific job duties. However, there are some key strategies that can be adopted to help reduce the use of force, regardless of the position or job.

  • Lift objects close to the body
  • Use good coupling or grip when lifting objects

Principles of lifting

  • Lift with the legs and keep the load close to the body
  • Load to be lifted should be below 50% of their personal strength limits
  • Minimise twisting with a load
  • Exercise care in slippery or cluttered areas
 Figure: The image shows the weight exerted on the spine from different types of lifting. When an object is held close to the body the weight exerted on the spine is less compared to when the object is far away from the body.
Figure: The image shows boxes with and without coupling/grip. The coupling/grip allows the hands to have a firm grip on the object, therefore reducing stress on the hand.
Figure: The image shows the guidelines for maximum handling loads for women and men.

 Principles of pushing and pulling

  • The area should be clear of obstacles
  • Push the load rather than pull (improves visibility ahead)
  • Use shoes that provide a good grip
  • When starting to push, brace one foot and use the back, not the hands and arms
  • Pushing/pulling is easier when the cart handles are about hip height
Figure: The figure shows two methods to move a heavy object. The rule is pushing is better than pulling when you want to move a heavy object as the action will have less impact on your upper and lower limbs. Pushing will only exert load on your lower limbs compared to pulling where you need to use your upper and lower limbs.

Use mechanical aids

The use of mechanical aid is recommended to reduce the risk of injuries.

Figure: The image shows workers moving heavy boxes with the aid of a trolley. The use of the trolley to move heavy objects will be able to reduce the risk of injuries and overexertion of the musculoskeletal systems
Figure: The image shows a nurse moving a patient using a hoist. The use of the hoist to move patients will be able to reduce the risk of injuries and overexertion of the musculoskeletal systems, especially the lower back.

2. Reduce Excessive Motion or Movement

The human body is designed to move in a way that is most efficient and comfortable. Understanding how the body moves and how excessive motion or movement causes physical and emotional stress will help us in our work. There are several ways to reduce excessive motion or movement. One approach is to use ergonomic devices and tools to reduce stress on the body. Another approach is to change the way that you move.

  • Let the tool do the work
 Figure: The image shows the use of a powered screwdriver to reduce repetitive motions.
Figure: The figure shows a worker removing objects from a box. In the picture on the left, the worker needs to pick the item from the box, this required more effort compared to the worker in the picture on the right where the item is slid onto the conveyer belt.

 

3. Maintain a neutral posture

It is important to always try to maintain a neutral posture while working. When in a neutral posture, the muscle and joints are in the least stressed situation. It will also reduce the compression of nerves and vessels. This will help to improve your circulation and reduce the risk of injury.

Figure: The image shows the hand and upper limb in neutral positions.

When in the neutral position, the muscles and joints are the least stressed and the nerves and vessels are not compressed as compared to the other positions of the hands and upper limbs.

Figure: The image shows the hands in various positions as compared to the neutral positions: that is, ulnar and radial deviations, and extension and flexion.

 

Figure: The images show the use of an ergonomically designed powered screwdriver which allowed the wrist to be maintained in a neutral position. The wrist is in ulnar deviation during the use of the normal screwdriver.
 Figure: The image shows the comparison of pressure on the intravertebral disc as compared to standing straight. If we take standing straight as exerting 100% of the pressure on the intervertebral disc in the other positions the impact on the intervertebral disc is between 140% and 275%, or 1.4 to 2.75 times more than standing straight.

It is important to always:

  • keep the back straight
  • keep the neck upright
 Figure: The image shows a standing workstation for office work. Working while standing will be able to reduce the load on the neck and back.

Even though standing workstations may reduce the load on the back, they will increase stress on the knee and feet. So it is important to ensure that when we are advising on any intervention to reduce ergonomic hazards, we need to ensure that it will not create new hazards.

4. Work at Proper Heights

When it comes to ergonomic work, proper heights are key. Proper ergonomic work heights can help improve your productivity and musculoskeletal diseases and stress. It is important to ensure that your main working area is at eye level.

You can practice the following when working at a computer workstation:

  • Work at elbow height (sitting or standing workstations)
  • The screen is placed at eye level.
Figure: The figure shows a sit-stand workstation: the worker can alternate between a sitting and standing position while working. The worker’s elbow is also at the same level as the keyboard while the shoulder is relaxed. The screen is also placed at eye level.

5. Keep Everything Within Easy Reach

With ergonomic design in mind, it’s important to make sure everything is within easy reach. This includes both the tools and the materials you’re working with. The things that you need to access regularly should be placed close to you without having to stretch your arms (Primary Work Zone) and things that are not commonly used can be placed further away (Secondary Work Zone).

 Figure: The image shows two work zones for a workstation: primary and secondary work zones. Things that are accessed regularly are kept in the primary work zone and things not used regularly are kept in secondary work zones.

6. Minimise Fatigue and Static Load

Another important point is to minimise fatigue and static load while working. Static load or static posture are conditions where the limbs are kept in the same position for a prolonged period of time. In the static load and posture, there will be a discrepancy between the blood supply and the blood needed for the proper profusion of the limbs.

 Figure: The image shows the blood flow to the upper limbs and the blood needed for proper profusion based on the different activities. Keeping the limbs moving, that is, avoiding static posture will increase the blood flow to the limbs.
Figure: The image shows the use of a footrest enables the worker to move and rest the lower limb while standing at work. This ensures that there is blood flow to the lower limb.

7. Minimise Pressure Points

Pressure points or contact stress reduces blood flow and compresses the nerves which interfere with nerve conduction. A decrease in blood flow will lead to fatigue of the limb and compression of the nerve will lead to pain. If the condition is prolonged then it may lead to permanent musculoskeletal conditions. It is important to reduce contact stress.

 Figure: The image shows the wrong position of the wrist and keyboard. An extended time in this position leads to pressure on the carpal tunnel and median nerve which may result in carpal tunnel syndrome.

Figure: The image shows that the lower limb is compressed by the table surface and the popliteal fossa is compressed by the chair.

8. Provide Proper Clearance

 

Figure: The image shows a proper workstation with adequate lower limb space and head clearance.

It is important to ensure that there is enough clearance so that the worker will not accidentally knock into objects and that the lower limb has enough space to move.

Figure: The image shows that the boxes are stacked too high and obstruct the visual field of the workers. This will lead to accidents as the workers can not see where they are going. It will also lead to neck strain as the worker needs to compensate to see where they are going.

When moving objects with a trolley, ensure to provide visual clearance.

9. Maintain a Comfortable Environment

It is important to maintain a comfortable environment while at work. This includes proper lighting, minimising noise and adequate ventilation, and at least 4-6 air changes per hour (ACH) in an office environment.

  • provide adequate lighting
  • avoid glare
  • use task lighting when needed
 Figure: The image shows conditions where there is reflected glare from the natural and artificial light, which may interfere with working on a workstation.
Figure: The image shows conditions where there is direct glare from the natural and artificial light, which may interfere with working on a workstation.
Figure: The image shows the proper placement of the workstation with both natural and artificial lighting providing adequate lighting and avoiding glare.

The amount of lighting required for work depends on the type of work being performed. In a general workspace where visual tasks are only occasionally performed the amount of light can be between 100-200 Lux (Lumens per square metre). For normal office works the lighting requirement is between 300 Lux for filing and 750 Lux for technical drawing. The amount of lighting increase with the increased need for detail work. For example performance of very prolonged and exacting visual tasks can be between 5000 and 10,000 Lux.

10. Move, Exercise, and Stretch

No matter how good a piece of equipment or the environment has been ergonomically designed to fit an individual. It is important to note that prolonged work in the same position will increase health and safety risks. It is important to always move. stretch and exercise.

Written by Victor Hoe

You can learn more about Managing Hazards and Risk at Work by joining the ExpertTrack on FutureLearn.

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