Ergonomics (Workplace and driving)

John McGregor

History of ergonomics

Ergonomics is the scientific study of human work and the work is

derived from the Greek ergon, work and nomos natural law

Bernadino Ramazzini originally highlighted the ergonomic problem

with musculoskeletal problems being described by clerks in the early

1700’s (de Morbis Artificum Diatriba (Diseases of Workers))

The word was coined as a result of a working party in 1949 requiring a

name for their research into the efficiency of the fighting man

In the United States, the term Human Factors is often used

Ergonomic principles

Ergonomics is the science of matching the job to the worker and the

product to the user

An effective match is one which optimises:

– Working efficiency (performance, productivity etc)

– Health and safety

– Comfort and ease of use

Problems with the working environment

• Standing

• Sitting

• Reaching

• Noise

• Unsuitable lighting

• Strenuous work

• Repetition

• High impact force on the upper

limbs

• Fatigue

• Changing shift patterns

• Thermal comfort

• PPE

• Different size operators

• Poorly designed alarms

• Unsuitable equipment

• Boredom

• Stress / anxiety

• Lack of training

• Poorly designed visual displays

• Backache / arm pain / headache /

other medical symptoms

Standing

• Humans are designed to stand on two legs but are not designed to

stand still

• Standing for long periods can lead to discomfort due to loads being

placed on the body

• People rarely stand still for any length of time – if not walking they

adopt a variety of resting positions

• In industry, standing work may prohibit the opportunity to practise

these behaviours due to design of the workplace

• Short periods of walking is vital to activate the venous pump and

therefore assist the return of blood from the lower limbs

The venous pump

The Venous Pump - which is

often called the "muscle pump"

or "peripheral heart" - depends

on:

1 Movement - of the leg and

particularly the ankle

2 Valves - situated in the veins

Standing still for long periods

may result in insufficient blood

return and fainting may occur

Characteristics of unconstrained standing

• Never stand still

• Bear weight on one leg

• Lean backwards against anything

• Lean sideways against vertical

surface

• Rest hand on head

• Rest pelvis against counter

• Maximise contact with fixed objects

• Rest one foot on an object

• Hang on elbows

• Sit on heels against a wall

• Use a footrest

• Sit down when tired

• Hang on to overhead objects

• Rest knee on something

• Lean over and rest hands on knees

• Use arms as a prop on work

surfaces

Victorian ergonomics

Footrest

Sitting

The Lacemaker

1669-1671

Differing postures

Normal chair Standing Saddle chair

Saddle chair

Spine retains ‘S’ shape ‘C’ shaped spine

Static work V dynamic work

Static

Poor exchange of blood

Build up of waste

Causes discomfort

May damage the muscle

Dynamic

Good exchange of blood

Exchange of nutrients and waste

Less likely to damage muscle

Static v Dynamic

Static posture of the shoulder

Static posture of the upper limbs

Anthropometry

This is the branch of the human sciences that deals with body

measurement and in particular:

• Body size

• Shape

• Strength

• Working capacity

What do you see?

Normal sized operator?

The Cranfield Man

Fitting the task to the human

Zones

Choose a car … any car

Correct choice?

Peugeot 207 convertible seat pan height 520 mm

Audi A3 convertible seat pan height 480 mm

Honda seat pan height 680 mm

Average Hip height for adults aged 45 – 65

male 910 mm female 805mm

Driver posture Guide

The Highways Agency suggest the following steps to set up a good

driving position:

• Raise the seat as high as is comfortable to improve your vision of

the road

• Move the seat forward until you can easily fully depress the clutch

and accelerator pedals

• Adjust cushion tilt angle so that the thighs are supported along the

length of the cushion

Driver posture Guide - cont

• Adjust the backrest so that it provides continuous support along the

length of the back and is in contact up to shoulder height

• Adjust the lumbar support to give even pressure along the length of

the backrest

• Adjust the steering wheel rearwards and downwards for easy reach

• Adjust the head restraint to ensure the risk of injury is reduced in the

event of a car accident

• Adjust the rear view and side mirrors ensuring that they can be used

without excessive straining of the neck or upper body

Repetitive Driving Injury (RDI)

• Study undertaken by eBay motors revealed that almost half of British

drivers (48%) are suffering from musculoskeletal pains due to poor

driving posture

• The 5 most common complaints are:

Foot cramp

Lumbar pain

Stiff neck

Side ache

Headache / eyestrain

Are you a rollercoaster or a pimp?

The rollercoaster (37% of population)

Driver leaning forward, sat upright,

seat forward

Common symptoms:

• Shoulder pain, neck strain, leg

cramp and side ache

Remedy

• Relax – tense, nervous drivers more

likely to adopt this posture. Take

regular breaks and stretch the legs

The multi tasker (26% of population)

Driver has straight back, arms bent,

one hand on gearstick. Almost half of

mobile office workers are multi-taskers

Common symptoms:

• Headaches, eyestrain, feet cramp and

coccyx pain

Remedy

• Adjust seat regularly, consider

automatic vehicle

The racer (19% of population)

Driver has straight arms, seat reclined,

straight legs and low driving position

Common symptoms:

Side ache and lumbar pain

Remedy

Be aware that low seat positions (and

bucket seats) provide limited back

support. Knees should not be higher

than your hips

The pimp (8% of the population)

• Seat reclined, arm on window ledge,

one hand on wheel. Typically male

drivers aged 25 – 35

Common symptoms:

• Arm and shoulder ache from resting on

the ledge (probably a bit of NIHL from

Dizzee Rascal being played too loud!)

Remedy

Sit upright with knees lower than the

hips. Keep both hands on the wheel

Proper driving footwear properties

The sole of the shoe should be no more than 10 cm, be too thin or soft

There should be enough grip to prevent the sole from slipping off the pedals

The shoe should not be too heavy or limit ankle movement

It should not be wide enough not to accidentally step on two pedals

Avoid

Dashboard Renault scenic

What information do I need to drive?

The car as an office

• Avoid using a laptop positioned on the passenger seat – this results in

severe twisting of the spine

• Store your laptop in the boot – at least you will change position and

get the opportunity to stretch your legs before work

• Try to find a suitable stop i.e service area so that the laptop can be

used on the table

• Avoid working with paperwork leaning ion the steering wheel

• Regular change of position is a must – take a break at lkeast every 15

minutes

• Ensure that you get out of the car and stretch your legs once you

have finished working and efore you set off on your journey

Avoid

Manual handling from a vehicle

• Park as close to the destination as possible

• Reverse in to gain extra space

• Clear all obstacles in your path

• Open doors if required

• Only carry what you can manage – use wheeled devices

• Do not overload – make several journeys

Unloading the vehicle

Good practice

Bad

Oh dear

Bad

Any questions?

Musculoskeletal disorders

Bernadini Ramazzini, the father of Occupational Medicine wrote in his

De Morbis Artificum of 1713, when referring to disease that affect

scribes and notaries:

‘the maladies that afflict the clerks aforesaid arise from the three

causes: first, constantly sitting, secondly the incessant movement of

the hand and always in the same direction, thirdly the strain on the

mind from the effort not to disfigure the books by error or top cause

loss to their employers when they add, subtract, or do other sums in

arithmetic’

Also known as ……

UK Work Related Upper Limb Disorder (WRULD)

Upper Limb Disorder (ULD)

Australia Repetitive Strain Injury (RSI)

Occupational Overuse Syndrome (OOS)

New Zealand Occupational Overuse Syndrome (OOS)

USA Cumulative Trauma Disorder (CTD)

Canada Repetitive Strain Injury (RSI)

Scandinavia Occupational Cevicobrachial Disorder (OCD)

Japan Occupational Cevicobrachial Disorder (OCD)

World-wide Work Related Musculoskeletal Disorder (WMSD)

Carpal Tunnel Syndrome

• Pressure on the median nerve as it

passes through the wrist

• Also known as nocturnal numbness

as the tingling can wake the

individual from sleep

• May be caused by repetitive type

work with a bent wrist or vibrating

hand tools

Lateral and medial epicondylitis

• More commonly referred to as

tennis and golfer’s elbow

• Inflammation of the area where

tendon and bone join. Lateral on

the outside, medial on the inner

• May be caused by repetitive,

forceful work

Reynaud’s phenomenon

• Work induced Reynaud’s commonly

referred to as Vibration White Finger

• Damage to the small vessels of the

fingers causing tingling, numbness

and weakness

• Caused by excessive use of

vibrating hand tools