This document provides an introduction to basic ergonomics. It defines ergonomics as designing work to fit human physical characteristics. Work-related musculoskeletal disorders are a major problem, accounting for over $1.5 billion in costs annually in Washington state alone. Common risk factors for these injuries include repetitive motions, forceful exertions, vibration, awkward postures, and heavy lifting. Jobs with these risk factors are considered "caution zone" or "hazard zone" jobs depending on duration and intensity of exposures. The document outlines various musculoskeletal disorders and provides examples of ergonomic hazards to avoid.
2. BASIC ERGONOMICSBASIC ERGONOMICS
Instructor: David Ellsworth
Edmonds Community College
This course is being supported under grant number
SH16637SH7 from the Occupational Safety and Health
Administration, U.S. Department of Labor. It does not
necessarily reflect the views or policies of the U.S.
Department of Labor, nor does mention of trade names,
commercial products, or organizations imply endorsement by
the U.S. Government.
With Thanks to & Cooperation of the Tulalip Occupational
Safety & Health Administration (TOSHA)
5. ERGONOMICS
What Does Ergonomics Mean?
Designing jobs, equipment, and work tasks to
fit human physical characteristics and energy
limitations
It considers body dimensions, mobility, and the
body’s stress behavior
“Make the work fit the person, not the person
fit the work”
6. ERGONOMICSERGONOMICS
Benefits of Ergonomics Include:
– safer jobs with fewer injuries
– increased efficiency and productivity
– improved quality and fewer errors
– improved morale
7. ERGONOMICSERGONOMICS
Ergonomic Goals:
Finding ways to make strenuous, often
repetitive work, less likely to cause muscle and
joint injuries -- and still get the job done.
Keeping young bodies from wearing out
prematurely, and mature bodies from giving
out early.
9. This type of injury affects nearly 50,000 Washington
workers each year
Enough People to Fill Safeco
Field!!
It is estimated that the actual
cost including lost taxes, wages,
fringe benefits, administrative
costs, etc. is close to $1.5 billion per year.
ERGONOMICSERGONOMICS
10. ERGONOMICSERGONOMICS
State Fund Claims - Statewide 1990-98*
WMSDs
All
other
claims
26%
74%
WMSDs
40%
60%
All
other
claims
Number of Claims Cost of Claims
Source: SHARP Report No. 40-4a-2000
* Note: This data does not include lower extremity WMSDs.
12. The Problem is WidespreadThe Top 12 Standard Industrial Classifications (SIC)
SIC Industry WMSDs per year
078 Landscape, Horticultural 420
152 General Bldg Contractors, Residential 1,361
174 Masonry, Tile, Plaster 703
175 Carpentry, Floor Work 429
176 Roofing, Siding, Sheet Metal 388
177 Concrete Work 287
242 Sawmills, Planing Mills 432
421 Trucking and Courier Services (non-air) 1,591
451 Air Transportation, Air Courier 411
541 Grocery Stores 1,486
805 Nursing, Personal Care Facilities 2,177
445836 Residential Care
Total 10,130
These 12 SICs alone account for 20% of WMSDs
Source: SHARP Report No. 40-4a-2000
13. 0 50 100 150 200 250 300 350 400
All WMSDs
Compensable WMSDs
Falls
Fractures
Ladders
Motor Vehicle
Head & Brain Injury
Electrical Apparatus
Conveyors
Burns
Rate per 10,000 FTEs
14. The Cost-Benefit Ratio
Is Substantial
Statewide
estimated
annual costs
to comply
with the rule:
Statewide
estimated
annual costs
saved by
ergonomics
prevention
$80
Million
$340
Million
The Estimated Savings to Business
Is $4 for Every $1 Invested
17. REGULATIONSREGULATIONS
Congress utilized the little known
Congressional Review Act (CRA) to pass a
joint resolution of disapproval of the new
OSHA Ergonomics Standard with the Senate
voting 56 to 44 on March 7 and the House
voting 223 to 203 on March 8, 2001
President Bush signed the joint resolution on
March 20, 2001
18. REGULATIONSREGULATIONS
The effect is that the OSHA Ergonomics
Standard is REPEALED – There is no
Federal Law!!
NOTE: OSHA still has some regulatory
“bite” in this area by virtue of
the infamous “General Duty
Clause” (OSHA Sec. 5(a)(1))
19. REGULATIONSREGULATIONS
OSHA General Duty Clause
Each employer “shall furnish to each of
his employees employment and a place of
employment which are free from
recognized hazards that are causing or
are likely to cause death or serious
physical harm to his employees”
20. REGULATIONSREGULATIONS
What’s Next ?
Several interested parties including Labor Unions,
Business and associations such as ASSE have been
meeting with Secretary of Labor, Elaine Chao to
formulate a new standard that will be acceptable to
all stake-holders
The federal ergonomics regulations are being
proposed on an industry by industry basis
23. ERGONOMICSERGONOMICS
WMSDs are:
– Daily stress to anatomical structures that may occur when
a person is exposed to certain high risk activities
– If the accumulating stress exceeds the body’s normal
recuperative ability, inflammation of the tissue can follow
– Chronic inflammation may lead to the development of
WMSDs
– May require weeks, months or years for development -
and for recovery
24. ERGONOMICSERGONOMICS
What is The Musculoskeletal System?
The Musculoskeletal System includes the following:
1. Bones – The load-bearing structure of the body
2. Muscles- Tissue that contract to create movement
3. Tendons – Tissues that connect muscles to bones
4. Ligaments – Tissues that connect bones to bones
5. Cartilage – Tissue that provides cushioning and reduces friction
between bones
6. Nerves – Communication system that links muscles, tendons and
other tissue with the brain
7. Blood Vessels – Tubes that circulate nutrients throughout the body
25. ERGONOMICSERGONOMICS
What Are Examples of WMSDs?
1. Sprain – Overstretching or overexertion of a
ligament that results in a tear or rupture of the
ligament
2. Strain – Overstretching or overexertion of a muscle
or tendon
3. Tendonitis – Inflammation of the tendon inside the
sheath
4. Tenosynovitis – Inflammation of the sheath around
the tendon
5. Carpal Tunnel Syndrome – Compression of the
median nerve as it passes through the carpal tunnel
in the heel of the hand
26. ERGONOMICSERGONOMICS
What are Examples of WMSDs?
6. Tennis elbow or Golfer’s elbow – Medical term is
Epicondylitis – inflammation of the tendons at the elbow.
7. Trigger Finger – Common term for tendonitis or
tenosynovitis that causes painful locking of the finger(s)
while flexing
8. Pitcher’s Shoulder – Rotator cuff tendonitis –
inflammation of one or more tendons at the shoulder
9. White Finger – Medical term is Reynaud’s Phenomenon –
constriction of the blood vessels in the hands and fingers
10. Digital Neuritis – Compression of the nerves along the sides
of the fingers or thumbs
30. Tendonitis
• Tendon function:
– Transmit force from muscle to bone
• Micro tears of tendon occur daily
• Typically repair themselves
• With repeated loading repair is not
adequate
• Pain / Inflammation
32. What Causes DeQuervain’s?
• Wringing washcloths, clothes
• Typing on the computer keyboard
• Cutting with scissors
• Sewing or pinching
• Stirring food for a long period of time
• Opening jars
34. Carpal Tunnel
• Best known MSD
• Compression of the
median nerve at the
wrist
• Tunnel made up of
nine flexor tendons
and one peripheral
nerve
• Numbness and
tingling on the thumb
side of the hand
44. ERGONOMICSERGONOMICS
WMSDs are sometimes referred to
using other unfamiliar terms such as :
1. Cumulative Trauma Disorders – CTD
2. Repetitive Trauma Disorders – RTD
3. Repetitive Strain Injuries – RSI
4. Repeated Motion Disorders – RMD
5. Overuse Syndromes
45. ERGONOMICSERGONOMICS
Signs or Symptoms of WMSDs
Painful joints
Pain in wrists, shoulders, forearms, knees, etc.
Pain, tingling or numbness in hands or feet
Fingers or toes turning white
Shooting or stabbing pains in arms or legs
Back or neck pain
Swelling or inflammation
Stiffness
Burning sensations
Weakness or clumsiness in hands; dropping things
48. Awkward Postures
High Hand Force
Highly Repetitive Motion
Repeated Impact
Heavy, Frequent or Awkward
Lifting
Moderate to High Hand-Arm
Vibration
Caution
Zone
Look for These Indicators:Look for These Indicators:
49. Awkward Postures
Being in these work positions for
more than 2 hours total per day
– Hands above head
– Elbows above shoulder
– Back bent forward more than 30 degrees
– Neck bent more than 30 degrees
– Squatting
– Kneeling
57. High Hand Force
More than 2 hours per day of:
Pinching 2 or
more pounds
weight or 4
or more
pounds force
58. High Hand Force
More than 2 hours per day of:
Gripping 10 or
more pounds
weight or
force
59. Highly Repetitive Motion
Workers repeat same motion every
few seconds for more than 2 hours
per day with:
– neck
– shoulders
– elbows
– wrists
– hands
63. Heavy, Frequent, or
Awkward Lifting
Lifting objects more than:
– 75 lbs. once/day
– 55 lbs. more than ten times/day
– 10 lbs. more than twice/minute
for more than 2 hours per day
– 25 lbs. above shoulders,
below knees, or at arms length
for more than 25 times/day
68. If the Employer Has
“Caution Zone” Jobs, They Should:
Begin an employee awareness
education program
Analyze the workplace for
hazards
Reduce any hazards they find
69. Ergonomics Awareness
Education Should:
Show the types, symptoms and
impacts of WMSDs
Show the importance of early
reporting of symptoms
Provide information on all “caution
zone” risk factors
Identify the hazards and measures
to reduce them
70.
71. Analyzing Caution Zone
Jobs for Hazards
Use a systematic method to look
at:
-physical demands
-layout of work area
-size, shape, and weight of objects
handled
The results will help to
determine controls
72. Hazard Zone
Risk factors become hazardous
when:
-there is a longer duration of exposure
-there is greater intensity
-there is a combination of risk
factors
77. Awkward Positions
•Back
–Bent forward >30°
Without support or
ability to vary posture
More than 4 hrs/day
–Bent forward >45°
Without support or
ability to vary posture
More than 2 hrs/day
80. High Hand Force
•Arms, Wrists, Hands
–Pinching unsupported
object 2 or more
pounds/hand
Or
–Pinching with force of 4 or
more pounds/hand (1/2 ream
of paper)
+
–Highly repetitive motion
More than 3 hrs/day
81. High Hand Force
•Arms, Wrists, Hands
–Pinching unsupported object
2 or more pounds/hand
Or
–Pinching with force of 4 or
more pounds/hand (1/2 ream
of paper)
+
–Wrists bent in flexion 30° or
more, or in extension 45° or
more, or in ulnar deviation
30° or more
More than 3 hrs/day
82. High Hand Force
•Arms, Wrists, Hands
–Pinching unsupported
object 2 or more
pounds/hand
Or
–Pinching with force of 4 or
more pounds/hand (1/2 ream
of paper)
+
–No other risk factors
More than 4 hrs/day
83. High Hand Force
•Arms, Wrists, Hands
–Gripping an unsupported object 10
lbs or > per hand
Or
–Gripping with force of 10 lbs or >
per hand (clamping light duty jumper
cables onto battery)
+
–Highly repetitive motion
More than 3 hrs/day
84. High Hand Force •Arms, Wrists, Hands
–Gripping an unsupported
object 10 lbs or > per hand
Or
–Gripping with force of 10
lbs or > per hand (clamping
light duty jumper cables
onto battery)
+
–Wrists bent in flexion 30°
or more, or in extension 45°
or more, or in ulnar
deviation 30° or more
More than 3 hrs/day
85. High Hand Force •Arms, Wrists, Hands
–Gripping an unsupported
object 10 lbs or > per hand
Or
–Gripping with force of 10
lbs or > per hand (clamping
light duty jumper cables
onto battery)
+
–No other Risk Factors
More than 4 hrs/day
90. Highly Repetitive Motion
•Neck, Shoulders,
Elbows, Wrists, Hands
–Same motion every few
seconds with little
variation
(Except Keying)
+
-No Other Risk Factors
More than 6 hrs/day
91. Highly Repetitive Motion
•Neck, Shoulders, Elbows,
Wrists, Hands
–Same motion every few seconds
with little variation
(Except Keying)
+
-Wrists bent in flexion 30° or more,
or in extension 45° or more, or in
ulnar deviation 30° or more AND
High, forceful exertions with the
hands
More than 2 hrs/day
92. Highly Repetitive Motion
•Intensive Keying
Awkward posture,
including wrists bent
in flexion 30° or more,
or in extenson 45° or
more, or in ulnar
deviation 30° or more
More than 4 hrs/day
98. How many lifts For how many hours per day?
per minute? 1 hr. or less 1 hr. to 2 hrs. 2 hrs. or more
1 lift every 2-5 mins. 1.0 0.95 0.85
1 lift every min. 0.95 0.9 0.75
2-3 lifts every min. 0.9 0.85 0.65
4-5 lifts every min. 0.85 0.7 0.45
6-7 lifts every min. 0.75 0.5 0.25
8-9 lifts every min. 0.6 0.35 0.15
10+ lifts every min. 0.3 0.2 0.0
Heavy, Frequent or Awkward Lifting
99. Manual Handling
• Manual handling is
transporting or
supporting a load by
hands or bodily force
- This includes:
• Lifting
• Carrying
• Putting down
• Pushing
• Pulling
• Moving
• Supporting
101. Hand-Arm Vibration
Step 1: Find the vibration value for the tool.
(manufacturer or web site:
http://umetech.niwl.se/vibration/HAVHome
.html or measure it yourself. The vibration
value will be in units of meters per second
squared (m/s²) - Using a hand-arm
vibration graph find the point on the left
side that is equal to the vibration value
102. Hand-Arm Vibration
Step 2: Find out how many total hours per
day the employee is using the tool and
find that point on the bottom of the
graph
Step 3: Trace a line in from each of these
two points until they cross
103. 0
10
20
30
40
50
0 1 2 3 4 5 6 7 8
Time (in hours)
Vibrationvalue(inm/s2
)
Example:
An impact wrench
with a vibration value
of 12 m/s2
is used for
2½ hours total per
day.
Hand-Arm Vibration
Note: The caution limit curve (bottom) is based on
an 8-hour vibration value of 2.5 m/s². The hazard limit
curve (top) is based on an 8-hour vibration value of 5 m/s²
104. Hand-Arm Vibration
Step 4: If that point lies in the crosshatched
“Hazard” area above the upper curve, then the
vibration hazard should be reduced below the
hazard level or to the degree technologically
and economically feasible
If the point lies between the two curves in the
“Caution” area, then the job remains a
“Caution Job”
If it falls in the “OK” area below the bottom
curve, then no further steps are necessary
105. Reducing Identified Hazards
Employers should reduce hazards to below
hazard level, or to a degree technologically and
economically feasible through:
– Engineering and administrative controls (preferred)
and/or
– Individual work practices and PPE
Employers might also consider reducing
employee hours performing a particular task to
lower the hazard of the job
108. ERGONOMICS
• Ergonomic hazards are prevented primarily by
the effective design of a job or job-site and the
tools or equipment used in that job
• Based on information gathered in the work-site
analysis, procedures can be established to
correct or control ergonomic hazards using
either engineering controls or work practice
controls
109. ERGONOMICS
• Thoughtful arrangements reduce stress and eliminate
many potential injuries and disorders associated with
the overuse of muscles, with bad posture, and with
repetitive motion
• Some jobs expose workers to excessive vibration and
noise, eyestrain, repetitive motion, and heavy lifting
• Machines, tools, and the work environment may be
poorly designed, placing stress on workers' tendons,
muscles, and nerves and in addition, workplace
temperature extremes may aggravate or increase
stress
110. ERGONOMICS
• Engineering Controls
• Work stations should be ergonomically designed to
accommodate the full range of required movements of
a worker
• Sufficient space should be provided for the knees and
feet
• Machine controls should be reachable and equally
accessible by both right and left-handed operators
• Other factors to look at include hard or sharp edges,
contact with thermally conducting work surfaces,
proper seating, work piece orientation, and lay-out of
the workstation
111. ERGONOMICS
• Engineering Controls
• Attention must be given to the selection and designs of
the tools used in the workplace to prevent the tools
from having a negative effect
• Workers should be permitted to test tools in the actual
work environment before purchasing new tools
• A variety of tool sizes should be available with
consideration to handle sizes, right and left-handed
workers, weight, center of gravity, and adequacy for
gloved hands
• Engineering adaptations may be made to tools and
tool handles
112. ERGONOMICS
• Work Practice Controls
• Key elements of a good work practice program
include instruction in proper work techniques,
employee training and conditioning, regular
monitoring, feedback, adjustments, modification, and
maintenance
• After workers are trained in a particular work
activity, such as proper lifting, they should be
monitored to ensure that they continue to use the
proper techniques
• Improper practices should be corrected to prevent
injury
113. STAY FIT FOR THE JOB...
“C’mon! Keep those stomachs
over the handle! Let the fat do
the work!… That’s it!”
114. Stretching
• Prepares muscles to do
work
• Flexible muscles not
easily injured
• Tight muscles easily
injured
– Morning/After Lunch
– Stress
– Previous strain/sprain
117. 90-degree" posture:
Sit upright with your elbows,
hips and knees bent at right
angles and your feet flat on the
floor or on a footrest
This position is biomechanically
correct, but it can fatigue your
back muscles over time
Fatigue can lead to slouching,
even on a chair with lumbar
support
118. Forward tilt posture:
Raise the height of your chair's seat
a few inches and tilt the front of it
downward about 8o
This will open up your hip angle and
allow you to support some of your
weight using your legs rather than
having it all rest on your hips and the
backs of your thighs
You may not find this posture
comfortable if you have knee or foot
problems, or if you feel like you are
sliding off the front of the seat - A
contoured chair seat can help to hold
you in place
119. Reclining posture:
Lean back 10o
- 20o
into the
chair's backrest and put your
feet out in front of you to open
up the angle at your hips and
knees
This helps relax your back
muscles and promotes blood
circulation
Leaning back too far however,
can result in an awkward neck
posture when trying to keep
your head upright
120. Standing posture:
Standing provides the biggest
change in posture, and is a
good alternative to prolonged
sitting, which can aggravate low
back injuries
It can be fatiguing, however, so
have a counter-height chair
available at standing
workstations, or use a height
adjustable sit/stand workstation
Also, prop one foot up on a low
footrest occasionally to help
shift your weight
121. ERGONOMIC INJURY FACTORS
• Lesions to tendons of the
neck, back, shoulders,
arms, wrists or hands
• Primary causes:
– Repetitive movements
over long periods of
time
– Awkward postures
– Use of excessive forces
122. ERGONOMIC SOLUTIONS: POSTURE
• NEUTRAL &
COMFORTABLE:
– Wrists straight
– Shoulders relaxed with
elbows close to body
– Head / shoulders &
back in vertical
alignment
– Frequent breaks when
bent postures can’t be
avoided
123. ERGONOMIC SOLUTIONS:
REPETITION
• Use automatic tools for repetitive tasks
(screw and bolt tightening)
• Eliminate unnecessary tasks / movements
by redesigning maintenance procedures
and workstations
• Take short, frequent breaks
• Alternate tasks and processes to use
different muscle groups
130. ERGONOMIC SOLUTIONS:
HIGH HAND FORCE
• Use clamps and fasteners
• Reduce weight of tool or object
• Redesign tool/user interface
• Look at Material Handling Alternatives
• Use Two Hands /Alternate Hands
• Sharp, well-maintained tools
• Alternate Positions/Tasks
145. ERGONOMIC SOLUTIONS
• Redesign hand-toolRedesign hand-tool
• Reduce weight of toolReduce weight of tool
• Rotate jobsRotate jobs
• Use clamps or visesUse clamps or vises
146. ERGONOMIC SOLUTIONS:
HAND TOOLS
• The design of grips for hand tools can be
crucial:
• Grip shape and size appropriate to the task and
user
• Isolate cold temperature
• Keep wrist and elbow in a "neutral" position
• Eliminate sharp edges or pressure points
• Use two-handed grips (where possible)
• Attenuate vibration
147. Redesign the Work StationRedesign the Work Station
Courtesy of UCDavisCourtesy of UCDavis
154. HAND-ARM VIBRATIONS
(HAVS)
• A disorder which affects the blood
vessels, nerves and muscles of the hand,
wrist and forearm
• Can be severely disabling
• Is better known as Vibration White
Finger
155. HAND-ARM VIBRATIONS
• Regular Maintenance
• Balancers, isolators, damping material
• Tool Selection
– low-vibration tools
– Battery rather than pneumatic operated tools
– High power to weight ratio
– Low torque w/cutoff rather than slip-clutch
– Non-slip surface
– Contoured handles
156. Why talk about HAVS?
• 1 Million workers are exposed to high
levels of vibration, of those 460,000 are
estimated to be working in construction
• 242,000 cases of HAVS are reported
every year
157. What are the Symptoms?
• Tingling and numbness in the fingers
• In the cold and wet, fingers go blue then red
and are painful
• You can’t feel things with your fingers
• Pain or tingling in your forearms at night
which stop you from sleeping
• Loss of strength in your arms and hands
159. Who is at Risk?
• Users of breakers
and pokers, sanders
and angle grinders
• Users of scabblers (to
clean concrete) and
needle guns
• Users of drills and
jigsaws
160. Who is at Risk?
• Those with a
disease that
reduces blood
flow
• Workers in cold
and damp
conditions
161. Who is at Risk?
Workers using
vibrating tools
Workers in
contact with cold
tools
162. How Can I Prevent it?
• Ask for low vibration
tools
• Try a different
approach to your job
• Use the right tool for
the job
• Keep blades and
cutting edges sharp
163. How can I Prevent it?
• Check to ensure that
the tool has been
properly maintained
• Reduce the amount
of time you use the
tool
• Keep the handles
warm
164. How can I Prevent it?
Improve your blood circulation by:
• Keeping warm, wearing gloves etc.
• Giving up smoking - Smoking drastically
impairs blood flow through the body
• Massaging and exercising fingers during
work breaks
165. Prevention
Low vibration tools
Use the right tool for the job
Tool maintenance
Reduce amount of time using the tool
Keep hands & handles warm
New approach to your job
Anti-vibration gloves
166. What Else Can I Do?
• Learn to Recognize the signs of HAVS
• Stop work and report any symptoms to
your supervisor immediately
• Use any control measures provided, i.e.
gloves etc., that your employer has
provided
• Ask for advice from your safety
department or safety rep
167. Remember
• Once you have had an attack of HAVS,Once you have had an attack of HAVS,
you will always be at risk (it is a chronicyou will always be at risk (it is a chronic
condition)condition)
• Tell your supervisor as soon as youTell your supervisor as soon as you
suspect any symptomssuspect any symptoms
170. CARPAL TUNNEL SYNDROME
• Occurs with repetitive motion of hands &
wrists--especially with high force levels
• Incidence up to 15% in certain industries
• A “natural” keyboard and good wrist support
can help most PC users avoid problems
• GOOD NEWS: Have dropped about 30% since
1990--which most attribute to strong workplace
ergonomics programs
171. Computer Ergonomics
• Routine PC user defined as spending 20
hours or more per week working at a
computer
• Studies of PC users have not shown a risk of
eye damage...although fatigue very possible
• NIOSH studies have not indicated a radiation
hazard nor pregnancy risk from PC usage
• Workers using bi/tri-focal glasses before
beginning PC use may need special purpose
glasses for computer work
172. “NATURAL” KEYBOARDS
• Three types:
1. Fixed split
2. Adjustable split
3. “Sculptured”
• Awkward wrist postures minimized
with 15 to 25 horizontal degree key
split AND 8 to 66 degree vertical
incline
175. “NATURAL” KEYBOARDS
• Key Layout Design Changes Have:
- increased comfort (81% of users)
– improved postures
– reduced muscle activity
– lowered carpal tunnel pressure in lab
settings
• Obtained primarily to alleviate an injury
176. WRIST RESTS
• No medical evidence that they reduce Repetitive Strain
Injuries...As they work for some, but not for others
• Usage Guidelines:
– Buy a rest that is even with top of keyboard
– Material should be “medium-soft” (foam--gel mix) so foam
doesn’t break down - AVOID hard plastic types
– DON’T leave wrists on rest...which compresses carpal tunnel -
Palm rest instead
– Changing typing habits more critical than wrist support
– MOST APPROPRIATELY USED TO REST HANDS
DURING PAUSE IN TYPING
• LEARN TO TYPE CORRECTLY WITH “FLOATING
WRISTS” FIRST!!!
198. Mouse – What it Does
In order to operate the mouse while typing, the
operator is frequently forced to reach forward or
sideways, or even both at the same time
206. Targeting the WorkTargeting the Work
• Targeting of large objects
can be performed at a
distance > 15 inches
• Targeting of small objects
need to be performed at
6-10 inches, ie., needle
and thread
220. MODEL COMPUTER WORKSTATION
• Keyboard trays WITH
wrist support
• Split "Natural"
keyboards to facilitate
neutral wrist angle
• Fully adjustable
ergonomic chair
• Document holder to
minimize head / eye &
neck movements
221. MODEL COMPUTER WORKSTATION
• Corner desk units to
position monitor directly
in front of employee
• Foot rest where
requested
• Re-organization of
working materials within
employee arm reach
• Alternative pointing
devices (e.g., scrolling
mouse or trackball
devices
226. Columns of Support
• Posterior column of support
– made up of the facet column
– very stable
– reflects an upright posture
• Anterior column of support
– made up of body of vertebra and the disc
– less stable
– reflects a flexed posture
227. The Disc & Nerve Root
• The disc is the
shock absorber of
the spine
• 85% water at the
age of 15
• 25% water at the
age of 75
229. Forward Bending
• Too much spinal
flexion
– loads the anterior
column of support
– places the posterior
wall of the disc at
risk
– has the potential for
nerve root
compromise
238. • A back injury costs an
average of $11,645 in
medical claims and lost time
wages.
National Safety Council
• Most back injuries can be
239.
240. The Forces Involved
The amount of force
you place on your
back in lifting may
surprise you!
Think of your back as
a lever - with the
fulcrum in the center,
it only takes ten
pounds of pressure to
lift a ten pound object.
241. The Forces Involved
If you shift the fulcrum
to one side, it takes
much more force to lift
the same object. Your
waist acts like the
fulcrum in a lever
system, on a 10:1 ratio
Lifting a ten pound
object puts 100 pounds
of pressure on your
lower back
242. The Forces Involved
When you add in the
105 pounds of the
average human upper
torso, you see that
lifting a ten pound
object actually puts
1,150 pounds of
pressure on the
lower back!
243. The Forces Involved
If you were 25 pounds
overweight, it would add
an additional 250 pounds
of pressure on your back
every time you bend over!
244. Common Causes of Back Injuries
Anytime you find yourself doing
one of these things, you should
think:
DANGER! My back is at risk!
Try to avoid heavy lifting
. . Especially repetitive lifting
over a long period of time
245. Common Causes of Back Injuries
Twisting at the
waist while
lifting or
holding a heavy
load . . . this
frequently happens
when using a shovel.
246. Common Causes of Back
Injuries
Reaching and lifting . . .
over your head, across
a table, or out the back
of a truck . . . .
247. Common Causes of Back Injuries
Lifting or carrying
objects with awkward
or odd shapes . . . .
248. Common Causes of Back Injuries
Working in awkward,
uncomfortable positions . . .
249. Common Causes of Back Injuries
Sitting or standing
too long in one
position . . . sitting
can be very hard
on the lower back . . . .
250. Common Causes of Back Injuries
It is also possible
to injure your
back slipping on
a wet floor or ice . . .
251. Prevent Back Injuries
• Avoid lifting and bending whenever you can
• Place objects up off the floor
• Raise/lower shelves.
• Use carts and dollies
• Use cranes, hoists, lift tables, and other lift-
assist devices whenever you can
• Test the weight of an object before lifting by
picking up a corner
• Get help if it’s too heavy for you to lift it alone
253. STEP ONE
Stand close to the load
with your feet spread
apart about shoulder
width, with one foot
slightly in front of the
other for balance
254. STEP TWO
Squat down bending at
the knees (not your
waist). Tuck your chin
while keeping your
back as vertical as
possible
255. STEP THREE
Get a firm
grasp of the
object before
beginning the
lift
256. STEP FOUR
Begin slowly lifting
with your LEGS by
straightening them -
Never twist your
body during this
step.
257. STEP FIVE
Once the lift is
complete, keep the
object as close to the
body as possible. As
the load's center of
gravity moves away
from the body, there is
a dramatic increase in
stress to the lumbar
region of the back
258. For those Awkward Moments...
If you must lift or lower from a high place:
1. Stand on a platform instead of a ladder
2. Lift the load in smaller pieces if possible
3. Push the load to see how heavy and stable it
is
4. Slide the load as close to yourself as
possible before lifting up or down
5. Get help when needed to avoid an injury
259. From hard-to-get-at places...
• Get as close to the load as possible
• Keep back straight, stomach muscles tight
• Push buttocks out behind you
• Bend your knees
• Use leg, stomach, and buttock muscles to
lift -- not your back
260. Team lifting
• All participants should be of similar
height, build and gender
• One person should take control of the
lift, command attention, inform others
and co-ordinate the lift
• Double the people DOES NOT MEAN
double the capacity
261. If one person can lift 100
pounds:
How much can two people lift?
Only 70 % or 140 pounds
How much can three people lift?
Only 50 % or 150 pounds
262. A. No. Manufacturers of back
support belts do not claim they
increase maximum lifting potential.
Q. Will wearing
a back support
belt increase my
maximum lifting
potential?
266. Things You Can Do
• Minimize problems with your back
by exercises that tone the muscles in
your back, hips and thighs
• Before beginning any exercise
program, you should check with
your doctor
267. Exercise!
Exercise regularly, every other day
Warm up slowly . . . A brisk walk is a
good way to warm up
Inhale deeply before each repetition of
an exercise and exhale when performing
each repetition
268. Exercises To Help Your Back
Wall slides to strengthen
your muscles . . . .
Stand with your back
against a wall, feet
shoulder-width apart.
Slide down into a crouch
with knees bent to 90 degrees
Count to 5 and slide back up
the wall - Repeat 5 times
269. Exercises To Help Your Back
Leg raises to strengthen back and hip
muscles . . .
Lie on your stomach
Tighten muscles in one leg and raise leg from floor
Hold for count of 10, and return leg to floor
Do the same with your other leg
Repeat five times with each leg
270. Exercises To Help Your Back
Leg raises to strengthen
back and hip muscles . . .
Lie on back, arms at your sides
Lift one leg off the floor and
hold for count of ten
Do the same with the other leg
Repeat 5 times with each leg
If this is too difficult… keep
one knee bent and the foot flat
on the floor while raising the
other leg
271. Exercises To Help Your Back
Leg raises while seated ...
Sit upright, legs straight and
extended at an angle to floor
Lift one leg waist high
Slowly return to floor
Do the same with the other
leg
Repeat 5 times with each leg
272. Exercises To Help Your Back
Partial sit-up to strengthen stomach muscles . .
Lie on back, knees bent and feet flat on floor Slowly
raise head and shoulders off floor and reach both
hands toward your knees
Count to 10
Repeat 5 times
273. Exercises To Help Your Back
Back leg swing to strengthen
hip and back muscles . . . .
Stand behind chair, hands on chair
Lift one leg back and up, keeping
the knee straight
Return slowly
Raise other leg and return
Repeat 5 times with each leg
274. Exercises To Decrease the
Strain on Your Back
Lie on back, knees bent, feet flat
on floor
Raise knees toward chest
Place hands under knees & pull
knees to chest
Do not raise head
Do not straighten legs as you
lower them
Start with 5 repetitions, several
times a day
275. Exercises To Decrease the Strain on
Your Back
Lie on stomach, hands
under shoulders, elbows
bent and push up
Raise top half of body
as high as possible
Keep hips and legs on
floor
Hold for one or two
seconds
Repeat 10 times, several
times a day
276. Exercises To Decrease the
Strain on Your Back
Stand with feet apart
Place hands in small of back
Keep knees straight
Bend backwards at waist as far as
possible and hold for one or two
seconds
Repeat as needed
277. A FEW SOLUTIONS...
• Reduce manual material handling
– Pre-Plan material drops
– Utilize material handling equipment
– Keep materials in “neutral zone”
• Equipment
– Use the right tool for the job
– Evaluate new tools for ergonomics
– Keep sharp & in good repair
– Use vibration dampening tools / gloves
• Reduce Duration
– Mini-breaks
– Multi-task
– Employee rotation/job share
283. Awkward Positions
• Adjustability
• Raise Worker or Raise Work
• Extending or Articulating Tools
• Tilt Tables
• Magnifiers
• Mirrors/Video for difficult access viewing
• Chest, Head, Arm supports
• Locate Objects w/in arms reach
• Alternate Positions/Tasks
284. It Costs Less to Be Safe
• Average Cost of
Common WMSDs:
1. Low back: $6,000
2. Shoulder: $7,000
3. Elbow: $4,000
4. Wrist: $5,500
• Average Cost of
Common Controls:
1. Hydraulic lift: $600
2. Adjustable height
workstation: $800
3. Powered screwdriver:
$100
4. Assembly work
positioner: $75
286. WE ARE HERE TO SHARE IDEAS!
“Okay! I’ll talk! I’ll talk…. Take two sticks of approximately equal
size and weight -- rub them together at opposing angles using short,
brisk strokes…”
287. START WITH A
STEERING COMMITTEE
• Designated Safety Coordinators
• Field Supervision
• Who must be involved-- to make a
positive impact in your company?
288. STEP ONE:
THE “CAUTION ZONE” INVENTORY
• Awkward Work Postures
• High Hand Force
• Highly Repetitive Motion
• Repeated Impact
• Heavy, Frequent or Awkward lifting
• Moderate to High Vibration
289. STEP TWO:
EMPLOYEE AWARENESS
• Education for affected employees
• Causes of musculoskeletal disorders
• Caution Zone Jobs of concern
• How to identify and prevent WMSDs
• Non-work related physical activities
• Promote physical fitness...
290. STEP THREE: ANALYSIS OF
CAUTION ZONE JOBS
• By the steering committee?
• By all field employees?
• By selected crafts or professions?
• Checklists or Pocket Cards?
• General or Specific Performance?
292. STEP FIVE:
GET EMPLOYEE INPUT & IDEAS
• Changes in tools or equipment
• Use of ergonomic PPE
• Reducing the size & weight of loads
• Ideas for task variety or job rotation
• Remember the impact of peer pressure
294. STEP SIX:
PRIORITIZE HAZARD REDUCTION
• Senior management support is needed
• Consider cost/benefits of changes
• Assign trial teams and a trial schedule
• Reduce exposures below hazardous levels, or
to the extent technologically and
economically feasible
295. STEP SEVEN:
COMPANY-WIDE APPLICATION
• Discuss experiments at safety meetings
• Assign new equipment or procedures
• Encourage continuing suggestions
• Keep ergonomic awareness high at safety
meetings, and during new employee
orientation
297. TOOLS & RESOURCES
• WorkSafe Institute of Washington
• OSHA Website
• Dept. of Labor & Industries
• The Internet – general information
search
• Ergonomic Equipment Suppliers
• Training Materials & Consultants
• Other?
298. Discrimination & Retaliation are Illegal !
– Employees have a legal right to report injuries
and raise safety and health concerns without fear
of retaliation or discrimination
– If an employee becomes disabled, an employer
must still comply with the Americans with
Disabilities Act (ADA)
– For ADA information, contact the federal
Department Of Labor at 1-800-949-4232 or the
Northwest Disability Business Technical
Assistance Center at 1-800-HELP-ADA
Editor's Notes
Ergonomics is a science that takes what we know about people’s capabilities and limitations, and applies that knowledge to the workplace.
Ergonomics is a tool that employers can use to make jobs, workstations, and tools to fit the worker. Employers who have implemented ergonomics in their workplaces have found that it greatly reduces injury claims and costs. They’ve found other benefits as well, such as increased productivity and product quality, and improved morale among employees.
Your head weighs 10 to 12 pounds, so it can be quite a strain to work with your neck bent.
Neck posture is only covered by the rule if the worker is not able to vary his or her posture. Working with the neck bent like this is pretty common in inspection jobs, such as with this cherry sorter. It also is common in job such as:
welding,
microscope work,
dental hygienists
Your upper body is 60 percent of your total body weight, so like your neck holding up your head, it’s also a strain for your back to hold you in a bent over position for more than two hours per day, such as landscapers who work near ground level.
Like neck posture, back posture is only covered if the worker is not able to vary his or her posture.
Squatting is one alternative to bending at the back to get down low, and it’s fine to do for short periods of time. Unfortunately it creates a lot of pressure behind the knee cap and can cause knee injuries over time.
Kneeling also is a risk factor for knee injuries, since it creates pressure both in front of and behind the knee cap.
A lot of construction work requires kneeling for jobs like concrete finishing, carpentry, and carpet and floor laying.
Squatting is one alternative to bending at the back to get down low, and it’s fine to do for short periods of time. Unfortunately it creates a lot of pressure behind the knee cap and can cause knee injuries over time.
Kneeling also is a risk factor for knee injuries, since it creates pressure both in front of and behind the knee cap.
A lot of construction work requires kneeling for jobs like concrete finishing, carpentry, and carpet and floor laying.
Using a lot of hand force increases the risk for hand, wrist and elbow injuries, and in some cases shoulder injuries.
Holding something between the tips of the fingers and the thumb is called a pinch grip. This type of grip uses very small muscles in the hand and wrist, so even holding something that weighs only 2 pounds can be a risk for injury if it’s done for more than 2 hours per day.
Because you can’t get as good a grip with your fingertips as with your whole hand, you tend to use more force to hold onto something than just the weight of the object. For example, in order to hold onto a stack of paper that weighs two pounds, you actually have to use four pounds of grip force.
Jobs involving pinch force of 4 pounds are also covered, even if the weight being handled is really low. An example would be an assembly job where one of the parts inserted are spring clips that require a pinch force of 4 pounds to open.
When you grip something with your whole hand you’re able to use the larger muscles in your forearm, and this gives you a grip that’s five times stronger than a pinch grip. You’re also able to get a better grip so the amount of grip force you use is pretty much equal to the weight of the object you’re holding.
Therefore, grip force only enters the caution zone if it’s 10 or more pounds of weight held or 10 or more pounds of force exerted, and it’s done for more than 2 hours per day.
Using a lot of hand force increases the risk for hand, wrist and elbow injuries, and in some cases shoulder injuries.
Holding something between the tips of the fingers and the thumb is called a pinch grip. This type of grip uses very small muscles in the hand and wrist, so even holding something that weighs only 2 pounds can be a risk for injury if it’s done for more than 2 hours per day.
Because you can’t get as good a grip with your fingertips as with your whole hand, you tend to use more force to hold onto something than just the weight of the object. For example, in order to hold onto a stack of paper that weighs two pounds, you actually have to use four pounds of grip force.
Jobs involving pinch force of 4 pounds are also covered, even if the weight being handled is really low. An example would be an assembly job where one of the parts inserted are spring clips that require a pinch force of 4 pounds to open.
When you grip something with your whole hand you’re able to use the larger muscles in your forearm, and this gives you a grip that’s five times stronger than a pinch grip. You’re also able to get a better grip so the amount of grip force you use is pretty much equal to the weight of the object you’re holding.
Therefore, grip force only enters the caution zone if it’s 10 or more pounds of weight held or 10 or more pounds of force exerted, and it’s done for more than 2 hours per day.
Just about every job requires some lifting, but lifting only becomes a risk for injury if it’s heavy lifting, it the lifting is done frequently, or if it’s done in an awkward posture.
For the caution zone, heavy lifting is any lift of 75 lbs or more once per day, or 55 lbs ten or more times per day.
Frequent lifting is 10 lbs or more, more than twice per minute, for more than 2 hours per day.
Awkward lifts are lifts of 25 lbs or more above the shoulders, below the knees, or out at arms’ length done more than 25 times per day.
Employees in caution zone jobs (and their supervisors) need to be provided with general ergonomic awareness education.
These jobs also need to be looked at in more depth to determine if they have hazards that require controls and to discover what is causing the hazards identified.
If hazards are identified, they need to be reduced below the hazardous level, or to the degree feasible. We’ll talk more about hazard levels and feasibility later.
These are the specific elements listed in the rule that need to be covered in the ergonomics awareness education.
Notice that information on all the caution zone risk factors is covered - this helps to make the education truly portable so that employees will be aware of different risk factors that may be present in any job they perform.
If you have employees whose jobs involve one or more of the risk factors we’ve talked about, then they are in the caution zone and they need to receive the awareness education. You also need to analyze these jobs to see if they are hazardous and need to be corrected. Your analysis needs to go beyond just whether or not there are risk factors, to try and find out what about the workplace or the job is creating the risk factors.
Physical demands include the risk factors we’ve talked about, but also the pace of work, whether the tasks are all the same or if there’s variety, and how much recovery or rest time there is between tasks.
Layout of the work area includes things like reaches, height of the workstation, chair, conveyor or whatever it is the employee works with or on to see if it is causing awkward postures.
Things you need to analyze for lifting jobs are the size, shape and weight of objects being lifted.
The point of this analysis is to see if a caution zone job is hazardous, and to help figure out the best way to control the hazard. For example, if the size and shape of a box requires workers to reach way out when lifting it, maybe a smaller box could be used.
Hazards that are identified during the job analysis need to be reduced below the hazardous level or to the degree technologically and economically feasible. The hazardous level would be that level specified in the General Performance Approach method chosen or in Appendix B if the employer is using the Specific Performance Approach.
We expect that in the large majority of situations there will be simple and affordable controls to reduce hazards, however the concept of feasibility recognizes there may be special situations where we may not yet know how to reduce the hazard below the hazardous level, or the control would not be economically possible for an employer. This feasibility issue is one we deal with in other safety and health rules too.
Engineering or administrative controls such as changes to workstations and tools, process redesign to eliminate unnecessary steps, or job rotation are preferred hazard control methods. If these are not effective in reducing the hazards below the hazardous level, the employer needs to use individual work practices or personal protective equipment (if feasible) as interim measures to supplement the other hazard controls.
The rule does not require an employer to replace full-time employees with part-time employees or otherwise reduce worker’s hours of employment to comply.
Abdominal muscles are most important muscles for preventing back strain/sprain/injury
PRO ATHLETES
RAILROAD
MAJOR CONSTRUCTION CO.
PRO ATHLETES
RAILROAD
MAJOR CONSTRUCTION CO.
PRO ATHLETES
RAILROAD
MAJOR CONSTRUCTION CO.
Job Enlargement- More variety in tasks
Mechanization –fit speed to safe work rate
Work-to-Worker. Rather than lifting, turning, repositioning have work arrive at worker in right position.
Job Enlargement- More variety in tasks
Mechanization –fit speed to safe work rate
Work-to-Worker. Rather than lifting, turning, repositioning have work arrive at worker in right position.
Idea is to reduce the force exerted. Look for ways to mechanically hold, lift, manipulate
Remember drawbacks to weight reduction (increase vibration)
Mat’l Handling alternatives. Rather than hand carrying items, use tool
Hammer with either hand. Grip or pinch with both hands
Mechanical devices – carpet stretcher rather than knee hammer
Increase weight – forces use of mechanical device, team lift, etc.
Handholds – increase lifting capacity by 15%
Horizontal distance – from pick-up point, to put down point, remove barriers, access obstacles
Common Work-Related Musculoskeletal Disorders
Keep in mind, WMSDs are not diagnoses; they are work-related disorders with similar characteristics.
Common WMSDs include:
Tendonitis (also Tendinitis). This condition is an irritation (inflammation) of a tendon resulting
from repeated force or stress on that muscle/tendon group.
Lateral epicondylitis (tennis elbow). This condition is an irritation (inflammation) of the tendons
attached on the outside of the elbow caused by activities that have jerky throwing motions or
impact (e.g., turning a screwdriver).
Medial epicondylitis (golfer's elbow).This condition is an irritation (inflammation) of the tendon
attachments on the inside of the elbow resulting from activities that require repeated or forceful
rotation of the forearm and bending of the wrist at the same time.
Tenosynovitis. Tenosynovitis is an irritation (inflammation) of the tendon and the lining of the
smooth sheath surrounding the tendon, resulting from repeated movement of the tendon in the
sheath.
Synovitis.Synovitis is an irritation (inflammation) of the inner lining of the membrane surrounding a
joint or tendon.
Stenosing tenosynovitis of the finger (trigger finger).This condition results from a tendon
surface becoming irritated and rough. If the tendon sheath also becomes inflamed and presses on
the tendon, a progressive constriction of the tendon can occur, resulting in a loss of free movement
in that joint area. This disorder is commonly caused, for example, by repeated use of a staple gun
or pair of pliers.
de Quervain's disease.This "disease" is a stenosing tenosynovitis affecting the tendons on the
radial side (e.g., thumb side) of the wrist. Constriction of these tendons pulls the thumb back away
from the hand, causing severe pain and limited thumb movement or use.
Raynaud's phenomenon (white finger or vibration syndrome).This "phenomenon" is caused
by the reflexive constriction of the small arteries, which causes the fingers to become white (pale)
and feel cold, numb, and tingly. This disorder may be caused, in part, by prolonged hand-arm
vibration from powered hand tools.
Thoracic outlet syndrome..This syndrome involves compression of the nerves and blood
vessels between the neck and shoulder. Symptoms include numbness of the fingers and hand.
Compression is due to various postures or activities, such as working with the arms above
shoulder height and pulling the shoulders back and down.
Minimize the manual handling as much as possible.
Plan your equipment/material drops
Use hoists, carts, wheelbarrows
Plan your lift. Check for:
Ease of route, obstacles, adequate space
The term HAVS is used to describe any damage to the blood vessels, nerves or muscles that is caused by vibration.
It is an encompassing title used to replace such terms as vibration white finger, drumstick finger and beat hand.
Numbness in fingers is dangerous as dexterity is lost. Any injury to the finger may not be felt and the body is then much more susceptible to disease and infection as the blood circulation to the finger is lost and the bodies defence system cannot reach the affected area.
The symptoms are usually after exposure to vibration.
When the fingers turn white blood flow is impaired and feeling is lost. As the blood returns the finger changes colour and becomes extremely painful.
. Stage 1 is where the tips of the fingers turn white. This is the point where the operative should raise the issue with site management.
HAVS is such a big issue that many companies who manufacture tools now make them low vibration. It is also mandatory for information on vibration created by tools is made available by the supplier.
The supplier has to provide the acceleration level of the tool expressed as m/sec2. The maximum exposure level is 2.8m/sec2 over 8 hours.
An assessment should be carried out to ensure that staff are not exposed to high levels of vibration. This can be carried out by the safety department.
Blunt blades and worn bearings can increase vibration in tools
Machines that are defective or not working correctly should be changed or repaired.
If possible reduce your exposure by job rotation, more or longer breaks ( not in the canteen, on different types of work!).
Use tools with plastic handles, steel handles are cold and tend not to keep warm.
Keep you hands warm to improve circulation, wear gloves and keep steel handles warm.
Smoking significantly reduces the bloods ability to flow to the extremities of the body.
In low temperatures the body attempts to keep the warm blood close the vital body organs such as the heart, lungs and kidneys etc. As a result the extremities of the body such as fingers and toes are starved of blood and sacrificed as part of the bodies defence mechanism.
Keeping the whole body warm and the hands ensures better flow of blood to the extremities.
Apparently placing your fingers in the warmest parts of your body when resting helps, such as your armpits and groin!
HAVS is such a big issue that many companies who manufacture tools now make them low vibration. It is also mandatory for information on vibration created by tools is made available by the supplier.
The supplier has to provide the acceleration level of the tool expressed as m/sec2. The maximum exposure level is 2.8m/sec2 over 8 hours.
An assessment should be carried out to ensure that staff are not exposed to high levels of vibration. This can be carried out by the safety department.
Blunt blades and worn bearings can increase vibration in tools
There are many styles and manufacturers of anti-vibration and impact gloves available on the market today -all with many different damping materials. Only gloves that are full finger in design should be considered “anti-vibration.” How do you know what to recommend to your employees?Proper glove selection largely depends on the type of job and the risk factors involved. The operation of a power tool requires an effective vibration-adsorbing material.
The U.S. currently does not have a standard in place to test the effectiveness of anti-vibration gloves. However, the International standard ISO 10819, followed by Europe and most of Asia, offers an effective guideline for anti-vibration certification. If vibration damping is the main concern, then you should only recommend the full finger certified glove.
Machines that are defective or not working correctly should be changed or repaired.
If possible reduce your exposure by job rotation, more or longer breaks ( not in the canteen, on different types of work!).
Use tools with plastic handles, steel handles are cold and tend not to keep warm.
Keep your hands warm to improve circulation, wear gloves and keep steel handles warm.
Not reporting HAVS will mean that the disease will only get worse. The fingers will eventually turn red then black. Infection can follow and in extreme circumstances fingers can be lost. Pain is severe and often felt only when resting.
Treatment and understanding at an early stage is crucial. HAVS is a chronic condition which means that it cumulates over a period of time. White finger will not occur straight away but builds up and can creep up on people unless they are aware of the symptoms.
It is a widely held opinion that many operatives detect the symptoms away from work and do not associate the problems with work activities and carry on until they can no longer work and drift away to other industries, or become so bad they never work again.
Here is a standard layout, with the mouse at one side of the keyboard.
In order to operate the mouse while typing, the operator is frequently forced to reach forward or sideways, or even both at the same time.
The main complaint is pain in the neck and shoulder region.
This is due to reaching forwards and sideways.
Repetitive movements are not so much to blame; rather it is the effort of holding one's arm with little or no support, often in an unnatural position, for a long time.
Therefore our focus must be on eliminating or at least reducing the need to place one's forearm and hand to the side of the keyboard.
Advantages of this platform:
Reduces side- and forward movements
Reduces the overall area of mouse operation
Disadvantages:
The mouse is located slightly higher then the keyboard – this defect can be alleviated by using a slightly higher arm support.
Notice that reaching forwards and sideways is substantially reduced.
Here is a keyboard with a touch pad for those applications that don’t require frequent and precise placement of the cursor.
A narrower keyboard (14”) allows one to operate the mouse without side movements.
A cordless mouse further minimizes discomfort, as one is not fighting a tangled cord all the time.
The minor disadvantage of having to adjust to a slightly different key arrangement is well counterbalanced by substantially increased comfort.
Placing the mouse between the operator and the keyboard requires using cordless mouse.
Individuals with shorter arms (and those who cannot get closer to the desk) may not benefit from such an arrangement.
Here's a solution for proof-reading thick and heavy documents.
To evaluate a worker's lifting habits, consider the following variables: frequency of lifting, duration of such activities, and type of lifting, as well as the worker's state of health, body size, age and general physical fitness.
Percentages: 1 person = 100 lbs, wrongly presume 2 people = 200 Rather take the 200 * .70 = 140 lbs 3 person presume 300 lbs, Rather take the 300*.50 = 150 lbs.
Preplan – ties to be delivered for a retaining wall. Arrange delivery at a location nearest the work area and oriented so they don’t need re-arranging. ½ at one end of the project, ½ at the other end. Or 1/3, 1/3, 1/3
Equipment – wheelbarrows, hoists,
Neutral zone – self-adjusting carts, stacks on more than 1 pallet to reduce bending for lowest items
These pictures show the difference between lifting and moving something heavy and awkward by hand (in this case a roll of carpet) and moving the same thing with the help of a co-worker and mechanical assistance (in this case a carpet dolly).
You can see where lifting by hand might create a risk for back or shoulder injury. The science of ergonomics teaches us that using the dolly puts a lot less strain on the back and shoulders, and it’s also less tiring overall. The worker who gets help is a lot more likely to have a little energy left at the end of the day, and in the long run is a lot less likely to have injuries and miss work.
Help may not always be available and it may not always be possible to use mechanical assistance. In some cases this type of help isn’t even needed. But when it is available and makes the job easier, then there’s no reason not to use it.
Ergonomics can be as simple as using a dolly to move something instead of lifting by hand. Ergonomics is about making jobs easier and reducing the risk of injury.
Adjustability: height, depth, ramps, footrests,
Raise: ramps, seats, stools, ladders, scaffolds, Work: Tables, tilt tables, pallets
Magnifiers: Head angle improvement
Mirrors: Don’t have to crank neck to see (I.e. forklift drivers)
For example, an employer cannot terminate an employee because he or she files a claim for worker's
compensation or complains about safety or health hazards.