Research summaries
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What is ergonomics?
Trying to help people understand ergonomics is by showing people how to perform safely, effectively, proficiently and comfortably within the working environment. Ergonomics is designed to reduce any additional pain or posture related injuries brought about by poor or sustained postures and repetitive movements. The approach is to help enable the individual to engage in activities more comfortably over long periods creating an increase in productivity without the fear that any wrong movement may cause an injury. All this is influenced by the efforts taken by the organisation and design of the persons work as well as factors such as seating, work heights and work environment. The diagram below illustrates the organisation's influence on ergonomics and well-being in the work-place.

Diagram: Ergonomic Model of Neck and Back Pain
(Source: Fig 22-9 Page 535 5th Edition Occupational Therapy and Physical Dysfunction)




Common ergonomic problems

Poor posture in sitting:
With the head, back and trunk in flexed/forward position results in fatigue of the muscles if this position is held for long periods or creating repetitive movements. Causes the pelvis to rock backwards, flattening out the low back lordotic curvature, stretching the ligaments that support the spine, fatigueing the musculature as well as increasing intradiscal pressures. Prolonged sitting prevents variation in movement, reducing flow of nutrients to the disc. So microbreaks are designed to encourage frequent changes in posture, increases blood flow and nutrients into the disc and other soft tissue structures and enable stretching of the low back musculature. (Occupational Therapy and Physical Dysfunction 5th Edition Annie Turner, Marg Foster, Sybil E Johnson pg 535)

Poor posture effects on the neck:
Must avoid head in the flexed postion for prolonged periods as well as having the head being rotated from the midline. OSH consideration to help benefit any clerical worker is to educate staff regarding posture, work pauses, and avoid oocupation overuse syndrome. To also provide adjustable tables, monitor stands and chairs for the operator. (Occupational Therapy and Physical Dysfunction 5th Edition Annie Turner, Marg Foster, Sybil E Johnson pg161-162)

Carpal Tunnel Syndrome:
There are two train of thoughts regarding what causing this very painful and sometimes debilitating condition.The first is the eight tendons of flexor digitorum superficialis and profundus run below the retinaculum in a common synovial sheath. The median nerve enters the hand by passing below the retinaculum. If the flexors and extensor muscles are overused and become inflammed in the synovial sheath, these can then compress down onto the median nerve causing Carpal Tunnel Syndrome.

The second in the dorsal and palmar interosseous radiocarpal ligaments lose their integrity due to continual flexion and extension of the wrist causing the carpal bones, especially the lunate, to lose their stability. In doing so this creates an unstable internal environment with the lunate bone dropping down , encroaching into the carpal tunnel. This will inturn cause the carpal tunnel, jamming the wrist as well as compressing the median nerve creating Carpal Tunnel Syndrome. The jamming effect will cause the flexor and extensor muscles to over work, over load and become inflammed within the synovial sheath. (4th Edition Anatomy and Human Movement pg 163-200. Palastanga, Field, Soames.)

The one thing that is very apparent among Anatomy, Ergonomic, Human Movement and Physiology authors is that the recients of Carpal Tunnel Syndrome are people who manually do repetitive movemnets caused in clerical, typists and computer operators.


Health & Safety Guidelines

The Health and Safety Executive are concerned at the escalating rise in musculoskeletal, fatigue and stress related injuries in clerical workers. An example of this extraordinary cost was a study done in 1995 where over a million people in the UK alone suffered with musculoskeletal injuries costing society over 5 billion pounds.

The Health and Safety Executive have published a Health and Safety Guideline manual with the view of drawing to everyone's attention the problems that are attributed to poor working environments. The onus in this manual to comply to these guidelines rests with the employers as they must ensure every step is taken to reduce musculoskeletal, fatigue and stress injuries to their employees.

Ill health can be as a result of poor equipment or furniture, work organization, work place environment, job design and posture.



There must be a built in recording system whereby the employer can create spontaneous assessments of the working environment ensuring continuity and accuracy of knowledge of work needs while allowing the employee the feeling of ownership over findings and at the same time creating a user friendly environment.

The key factor to come out of the guidelines regarding the ways of reducing fatigue and stress was the need to create, integrate and implement breaks in or change activities whilst at their workstations. Fatigue and stress are the second highest cause of occupation ill health to musculoskeletal strain/sprain related conditions.

Research shows the attributing factors are prolonged or particular intense periods of stress can lead to physical or mental ill health. Stress can be created by workload, inadequate workstation environment, upper limb disorders, low back injuries and workers having no input or control into their working environment.

The nature and timing of breaks or changes in activities are designed to allow the user to vary their posture, to perform precise well constructed exercises all with the objective to stretch the various body regions. While increasing the blood flow through the body this will decrease the onset of fatigue. It is preferred to have more frequent/less duration breaks than less frequent/longer duration breaks as it will create better blood flow and muscular activity.

Research has shown that taking routine breaks does lead to increasing productivity because the breaks are being used before fatigue or stress sets in. However the user must be discouraged from using the computer during these breaks for if anything the users mental and physical status. The guidelines stipulate that seating and posture for a typical office work station should have:

1) Height adjustable seat

2) Wrists not excessively bent

3) Forearms horizontal

4) Screen height positioned correctly

5) Space in front of keyboard to support forearm,hands and wrist

6) Data collecting software to enable informative analysis to be performed on any employee.

Conclusion
The objective of designing the HiLo table was to comply with all the guidelines set out by the Health and Safety Manual in trying to create a user friendly environment and therefore reducing the possible onset of musculoskeletal injuries, fatigue and stress to the employee. I believe that the fully automotive and personalized HiLo table has all the components to create a zero postural stress on the user.


Common injuries

• Somato-psychic - where the fatigue of the muscles and the ligaments create mental stress problems.

• Somato-somatic - the small muscles fatigue transferring the load to the bigger muscles creating fatigue in the bigger muscles.

• Somato-visceral - muscles supporting spine fatigue causing increased blood pressure, heart problems, headaches and migraines.

• Psycho-visceral - mental stress causes increased blood pressure, heart problems, ulcers, headaches and migraines


Accident Compensation Corporation Statistics

$21 million dollars was spent in 2005 on ACC work environment claims.
(Source: ACC 2005)