Ergonomics is the study of work performance and how the worker and the job demands influence each other. Ergonomics takes into consideration knowledge about human abilities, limitations and other characteristics and looks at the interaction between those factors and the characteristics of the job being performed. Ergonomics focus is to create a safe, easy to use, comfortable and efficient worker and job demand interaction.
The UW-La Crosse Environmental Health and Safety Office strives to improve ergonomic conditions on this campus. There are various informational resources on ergonomics that are available to UWL faculty, staff and students. The resources include consultation and programming provided by the UW-La Crosse Environmental Health and Safety Office. There are also a variety of videotapes and books available through Murphy Library. Finally, UWL Environmental Health and Safety has created bulletins and newsletters that can be accessed through this web sight as well as ergonomic guideline resources that can assist in creating a more ergonomically designed work environment.
An ergonomic consultation can be done for two reasons. First it can be done in response to a worker developing a musculoskeletal disorder and requiring a restructuring of their work environment to decrease the risk of the musculoskeletal disorder worsening. A second reason is to prevent a musculoskeletal disorder. Musculoskeletal disorders are cumulative, they develop over time and in the beginning an individual may not notice that an injury is occurring because with a normal nights sleep any discomfort goes away. During an ergonomic consultation it may be discovered that a slight modification can be done to the worksite to decrease the risk of developing a musculoskeletal disorder. An ergonomic consultation involves looking at the worker, the work and the work site to identify the problem and determine the most effective method of solving it.
The Environmental Health and Safety Office can provide consultation to UWL employees. In some cases resources or guidelines will be provided to supervisors or other appropriate personnel to evaluate the work task or station.
Contact Environmental Health and Safety to request an ergonomic evaluation of your worksite and operations.
The following ergonomic videotapes are available for check-out in Murphy Library. These videotapes are located in the Video Collection on the second floor of Murphy Library. They can be used to train UWL employee's or student's on a variety of ergonomic topics pertinent to our campus environment. The videotapes can be incorporated into class lectures or Department's may wish to schedule meeting(s) to discuss these important topics. The available videotapes are listed and described in the remainder of this bulletin. If you have any questions, comments or requests for additional ergonomic materials please contact Dan Sweetman at 785.6800, 235 Graff Main Hall.
Title: Office Ergonomics
Catalog Number: HD7261 .O3337 1995
Description: Teach employees how to avoid unnecessary strain and stress on the body. Topics include: neutral work postures, techniques of good posture, lifting techniques, avoiding repetition, exercise importance, and customizing the work space.
Length: 11 minutes
Title: Safe Lifting
Catalog Number: T55.3 .L5 B3 1995
Description: Back injury prevention training is essential for all employees. This training includes lifting guidelines and techniques, the importance of exercise and general back musculoskeletal structure.
Length: 5 minutes
The following ergonomic books are available for check-out in Murphy Library. These can be used to train and inform UW-L employee's or students on a variety of ergonomic topics pertinent to our campus environment. The available books are listed and described in the remainder of this bulletin. If you have any questions, comments or requests for additional ergonomic materials please contact Dan Sweetman at 785.6800, 235 Graff Main Hall.
Title: Ergonomics, Work, and Health
Call Number: RC967.P525
Author: Pheasant, Stephen
Description: This book discusses the role of ergonomics in the promotion of health and safety at work. It is particularly concerned with work-related musculo-skeletal disorders and the range of conditions affecting the neck, shoulders and upper limbs which have come to be known as "repetitive strain injuries." Related issues, such as stress, occupational accidents and the role of human error in complex, man-made systems, are also discussed, This book is written for a wide range of specialist and non-technical readers.
Location: 2nd floor stacks
Title: Carpal Tunnel Syndrome & Overuse Injuries: Prevention, Treatment & Recovery
Call Number: RC422.C26 C76
Author: Crouch, Tammy and Madden, Michael
Description: This book shows how alternative therapies, holistic medicine and chiropractic services can enlarge the range of treatment choices beyond anti-inflammatories and surgery. The authors explain the condition and its causes, how to get help and the stages of healing. This book will help you make changes in work habits, lifestyle, diet and attitude necessary to recover from Carpal Tunnel Syndrome and other overuse injuries.
Location: 2nd floor stacks
Title: Carpal Tunnel Syndrome: Prevention and Treatment
Call Number: RC422.C26 M652
Author: Kate Montgomery
Description: This book will teach you how to keep healthy, work productively, treat symptoms of repetitive strain injury early and prevent harm. It will teach two-minute self-corrections that give you peace of mind. It will teach you how to relieve pain non-surgically through skillful self-help and it will introduce a program that can be done in the office or at home.
Location: 2nd floor stacks
Title: Concouring Carpal Tunnel Syndrome and other Repetitive Strain Injuries - A Self Care Program
Call Number:RC422.C26 B88
Author: Sharon J Butler
Description: You will learn everything you need for true self-care. Learn how soft tissues function and why they develop repetitive strain injuries. Discover how gentle stretching can help restore full function and comfort to your hands, arms , neck and shoulders. Choose the most appropriate exercises to relieve your symptoms by reviewing the symptoms charts included in this program. Create an effective Injury Prevention Program based on your occupation.
Location: 2nd floor stacks
Title: Ergonomics for Therapists - 2nd Edition
Call Number: RM735.E73
Author: Karen Jacobs
Description: Acquire the knowledge, tools, and techniques necessary for understanding ergonomics. This unique text provides an introduction to ergonomic concepts and discusses their application to clinical practice. Learn the skills you need to analyze work environments, change work habits and prevent injury.
Location: 2nd floor stacks
Title: Ergonomics in computerized offices
Call Number: HF5547.5.G693
Author: Grandjean, Etinenne
Description: This book explains the procedures that should be adopted to remove ergonomic office problems and how the problems can be avoided in the first place by the appreciation and application of correct ergonomic principles and practice.
Location: 2nd floor stacks
People vary widely in their shapes and sizes, and the chairs they use should reflect this characteristic. Workers should be able to select from a variety of different chair models.
A "poorly fitting" chair may introduce musculoskeletal problems or aggravate existing conditions. Compressive forces on the spine are greater when sitting than when standing. Fatigue and discomfort result when muscles and joints are forced into awkward postures, especially after prolonged sitting.
The chair is the most intimate piece of equipment the office worker has, yet it is often overlooked in the design of a workstation. Whether in a conference room, or at a computer workstation the chair must be designed with function in mind. For example, a cozy, stylish conference chair may present problems for the office worker who types for a long period of time each day.
Currently there are no restrictions on using the term "ergonomically designed" to describe chairs or any other type of office furniture. Pay attention to the claims made by chair manufacturers.
Fitting the Population
The chair must adjust to the size and comfort of each worker. Not only should the chair raise and lower to accommodate varying heights, but the seat depth should adjust as well. If the seat depth of the chair is too great, the back support cannot be used.
An adjustable seat angle is beneficial for the office worker. A forward sloping seat, or "waterfall front," is helpful to relieve pressure on the backs of the legs while the worker is typing or writing. A 5 degree backward slope promotes use of the backrest and prevents the worker from sliding forward. The backrest should support the lumbar spine but not restrict its movement.
The armrest should be adjustable for height, width between armrests and distance to the seat front. These adjustments are important for reducing the pressure on the seat surface and the load on the spine. The length and width of the armrests must be considered. Armrests can become obstacles when they are too wide or too high (e.g., armrests that prevent a chair from sliding under a table). When awkwardly positioned, armrests may hinder a worker getting out of the chair. Five casters are necessary to prevent the chair from tipping. The casters must roll over carpeted surfaces easily.
The chair evaluation checklist, below, should guide you in selecting a chair that can be adapted to your individual needs.
Chair Evaluation Checklist
Any questions answered NO indicates a potential problem area.
- If the seat is fixed height, is the top of the seat 8 to 19 inches above the floor height?
- If the seat is adjustable, is the top of the seat 16 to 20.5 inches above the floor height?
- Does the top of the seat adjust from an angle of 5 to 15 degrees forward tilt to 5 degrees of backward tilt and lock in place?
- Is the seat 15 to 17 inches deep (i.e., does the seat back move in over the seat pan)?
- Is the top of the seat at least 18 inches wide?
- Does the seat have a rounded, waterfall front seat edge?
- Does the amount of contouring support postures, distribute pressures, and provide freedom of movement?
- Does the seat cushion thickness range from 1.5 to 2.0 inches?
- Does the seat covering "give" and "breathe"?
- Is the seat back angle a minimum of 90 to 105 degrees (preferably up to 120 degrees), and does it lock in position?
- Is the seat back width in the lumbar region at least 12 inches?
- Is the seat back 15 to 20 inches high?
- Is the height of the lumbar support adjustable?
- Does the lumbar support move upward relative to the lumbar spine as the backrest reclines?
- Is the lumbar support 6 to 9 inches long and 12 inches wide?
- Is the lumbar support positioned 6 to 10 inches above the seat?
- Does the lumbar support protrude forward about 2 inches from the back of the seat?
- Does the chair have a stable five-point base with casters?
- Does the chair have adjustable armrests?
- Are the armrests 9 to 12 inches long and 8 to 9 inches above the seat?
- Is the chair easily adjustable?
- Can the controls be easily reached and adjusted from the standard seated work position?
- Do the controls provide immediate feedback?
- Is the direction of operation of controls logical and consistent?
- Do adjustments require the use of only one hand?
- Does the chair pivot 360 degrees, allowing easy ingress/egress and access to various surfaces?
Know where you are going to lift a load. Pre-plan your lift.
Get a firm footing: Keep your feet apart (shoulder width) for a stable base and good balance; point toes out.
Bend at your knees and hips: Don't bend at the waist. Keep the principles of leverage in mind. Don't do more work than you have to. Maintain your three natural back curves.
Tighten stomach muscles: Abdominal muscles support your spine when you lift, off setting the force of the load and protect your back. Train muscle groups to work together.
Lift with your legs: Let your powerful leg muscles do the work of lifting, not your weaker back muscles. Maintain you three natural curves.
Lift smoothly; don't jerk as you lift. Suddenly movement and weight shifts can injure your back.
Keep load close: Don't hold the load away from your body. The closer it is to our spine, the less force it exerts on your back.
Keep your back upright: Whether you are lifting or putting down the load, don't add the weight of your body to the load. Your nose and your toes should be facing up when lifting.
Turn with your feet: Avoid twisting; it can cause injury.
Many Musculoskeletal Disorders (MSD's) occur in the hand or arm. The below image shows five hand positions that put additional pressure on the muscles, tendons, and nerves in your arm and can lead to MSD's. Try to remember to keep your hand out of these positions as much as possible. If your hand must be in these positions remember to take rest breaks and stretch your hand in the opposite position to relieve the pressure on your arm.
- Light should be adequate for operator to clearly see text and screen, but not bright enough to cause direct or reflected glare.
- Light diffusers for fluorescent light fixtures should be considered for the area.
- Task lighting should be considered for more demanding visual tasks such as proof reading and working with poor quality photocopies.
- Position computer screens at right angles to windows to minimize reflection and glare.
- Provide non-reflective screens (e.g., anti-glare filter) and keyboards (e.g., matte finish).
- Work surfaces around the screen should be non-reflective.
- Consider using blinds or curtains if sunlight is to bright or hot.
- High gloss and brightly colored paints should be minimized on office walls and ceiling.
- Position screen so that artificial lighting does not reflect from the screen.
- If you are having trouble identifying the source of the glare hold a mirror in front of the computer screen.
- Noise may increase operator stress and thus fatigue. Take steps to limit excessive or annoying noise from operation of equipment or machinery. Contact the campus Environmental Health, Safety and Risk Management Office for noise control assistance.
- Ventilation should be provided to all work area's to maintain personal comfort and acceptable indoor air quality.
Contact the Environmental Health, Safety and Risk Management Office to assist with analysis of indoor air quality concerns. Contact Facilities staff for analysis and repair of ventilation systems.
II. WORKSTATION DESIGN
Chairs should be adjusted to fit the user. Below are recommendations for ergonomic chairs, but it is important to understand that numerical values may fluctuate depending on the person. Comfort is the key factor in determining if a chair is fitted properly.
- Chair should easily adjust - preferably a pneumatic lift to allow easy adjustment of the entire chair to suit the task at hand.
- Seat height
- The seat adjustment range can be determined by measuring the work level from the floor and subtracting 12 inches. That number should be the midpoint in seat adjustment range.
- For a standard desk chair 15.5-20 inches is recommended.
- Upper legs should be almost parallel with the floor (90 degree angle at the hip joint).
- Seat pan
- Width should be at least one inch wider than your hips and thighs on either side (17 to 19 inches is the average recommendation).
- Depth should be no less than 17 inches and should be adjustable either by a backrest with in-out adjustability or sliding seat pan to allow good stability and proper use of the backrest.
- Slope should be within a range of adjustability from 0 to 7 degrees.
- The seat should be contoured so to allow weight distribution through buttocks and upper part of thighs only.
- There should be 1-5 inches from the front edge of the chair to the back of the knee so that there is no pressure on back of knees or underside of thighs
- The seat should have a rounded front edge to reduce pinching and improve blood flow to lower leg.
- The seat should have 1-2 inches of padding with breathable upholstery.
- Width of 13 to 14 inches
- Height of 6 to 20 inches.
- Lumbar support is done through gentle curves in the backrest shape and should be 4 to 10 inches to affect the size and firmness of the lumbar support and accommodate for different preferences and body shapes.
- Height adjustability should allow individuals to change how the lumbar support curve contacts the back and should move up and down within a 7 to 10 inch range.
- In and out (forward) adjustability of 12 to 17 inches
- Tilt angle of 5 to 30 degrees
Armrests should only be used periodically because they can lead to arm, wrist and shoulder problems. Armrests can interfere with you getting close to your work, so adjustability is essential.
- Height should be 7 to 11 inches
- Length should be 6 to 10 inches
- Width should be a minimum of 2 inches
If arm rests are being used shoulders should be relaxed not elevated.
- Chair should swivel if twisting is necessary.
- Any chair with mobility should have at least 5 castors for increased support.
- Ensure person is positioned correctly with proper chair height and back support in the small of the back then check whether person is able to comfortably place both feet on the ground.
- Footrests should have adjustable height and surface area large enough to comfortably accommodate both feet.
- Footrests should be 12 x 16 inches with an angle of 25 to 30 degrees. A non-skid surface is recommended.
- Keyboards should be separate from the computer screen to allow for independent adjustment - powerbooks and laptops are not designed for long term keyboarding.
- Upper arms should be at the operator's side with a 90 degree angle at the elbow (keyboard home row height 23-28 inches - a standard desk is 30 inches off the ground which is too high for typing for extended periods of time.)
- Keyboard slope should be adjustable from 0-25 degrees.
- Wrist pads should be considered for the edge of the keyboard support surface and should be used only during typing breaks, hands should float above keys during typing with the wrists kept straight.
- Keyboard should be replaced if keying requires excessive force.
- Key tops should be dished to minimize slipping of the fingers.
- Keyboard and keys should have matte finish to minimize glare.
- The top of the computer screen should be just below eye level (mid-screen height 37-43 inches). The viewing angle should be 5-20 degrees. Individuals who wear bifocals should pay attention to monitor placement and lower computer monitor or purchase glasses designed for computer work to avoid tiliting their head back to read the screen through the lower part of the bifocals.
- The screen should be tilted back slightly (maximum 15 degrees).
- Viewing distance (eye to screen) should be approximately arms length (between 20-30) inches.
- Adjust screen brightness, contrast, etc. for comfortable viewing.
- Screen display should be free from flicker.
- Screen should have a minimally reflective surface.
- Character display should be a size (3/16 inch), color and quality that ensures legibility.
- Use a footrest if the chair or table is to high.
- Use a document holder that is located just to the left or right of the screen. The copy holder should be adjusted to maintain the document at the same height as the screen and the same distance from the operator's vision.
- Keyboard and screen should be directly in front of the operator. The screen viewing angle should be between 0-15 degrees.
- Writing surface should be provided (minimum dimensions 12 by 16 inches, optimum 30 by 30 inches).
- L-shaped workstations should be considered for operators who perform varied tasks (e.g., writing, typing, attending to a printer, etc).
- The work surface should be at about elbow height and there should be a 90 degree angle at the elbow joint.
- The work space should allow sufficient leg space. Minimum width of 31 inches, minimum depth of 25 inches and minimum height of 26 - 28 inches.
- When typing the wrists should be in line with the forearms and not bent forward or backward or side to side.
- A matte finish should be used to minimize reflection.
- Rounded corners on workstations are recommended so that arms and wrists do not come in contact with any sharp or square edges.
- Frequently used items should be kept with 10 inches of the individual to minimize reaching and occasionally used items within 20 inches.
- Enough work surface should be available for all computer accessories.
- Use a headset if a large portion of time involves using the phone.
- Arm should be supported, at the side, and close to the body, with elbow at about work surface height. Upper arm and forearm should be at about 90 degrees. Position should allow the forearm to move, not the wrist (avoid ulnar or radial deviation). The wrist should be in line with the forearm (avoiding extension and flexion of the wrist).
- The mouse should be kept at the same level as the keyboard and as close to the centerline of the body as possible.
III. TASK CONSIDERATIONS
- Maintain the body in a position that is neutral or comfortable.
- Do not hold a telephone between your neck and shoulder.
- Your chair must be adjusted properly to be effective. No single position is appropriate for extended periods of time. Be sure to stand, stretch and take frequent breaks.
- Operations that require one hand on the keyboard with the other thumbing through a document may require the keyboard to one side and document in front.
- Eye strain is often caused by eye muscles holding a particular focal distance and so may be alleviated by changing your focal distance. A wall hanging or poster, which allows the operator to focus on a distant object (preferably something at least 20 feet away)will offer visual relief and help reduce eye strain.
IV. ADMINISTRATIVE CONTROLS
- Exercise is one of the most effective steps in avoiding the effects of excessive force, awkward position and repetitive motion.
- Take several brief stretch breaks throughout the day. Stretching improves blood flow and rejuvenates working muscles.
- Implement a voluntary daily exercise/stretching program in your work area.
- Periodically exercise your eyes to reduce visual fatigue. One simple exercise is to focus your eyes on objects at variable distances. In addition, use corrective lenses if needed
- Take periodic breaks to stretch working muscles and reduce eye strain - one 15 minute break at least every two hours.
- Rotate jobs to avoid constant keyboard work.
- Change positions frequently.
- OBJECT CHARACTERISTICS
- Keep the size and weight of the object being lifted as small as possible.
- Lift balanced loads so you do not have to apply forces to control a moving center of gravity.
- Lifting is not recommended above shoulder height or below knee height. Store light objects up higher.
- Keep the load as close to the body as possible.
- Avoid forward leaning or bending and lateral bending when lifting.
- Avoid twisting while lifting.
- Maintain good balance and footing.
- Keep the back straight when lifting.
VI. GENERAL OFFICE SAFETY
- Use elevators to carry loads up stairs.
- Good housekeeping is important.
- Floor surfaces should offer good traction.
- Aisles should be wide enough and remain clear of tripping hazards.
- Use the correct tool for the job. Do not stand on chairs, properly use ladders or step stools.
- Maintain the 3 normal curves of your spine as often as possible
- Sit back against your chair - don't sit slumped in any furniture
- Plan ahead before lifting
- Keep the load you are lifting close to your body
- Get help with a lift if you think it may be too heavy
- Bend your knees or squat when reaching items below your waist (even if you are just picking a pen up off the floor)
- Pivot, don't twist
- Push versus pull (you are stronger pushing than pulling)
- Change positions frequently, and take breaks to stretch if you have to sit or stand for prolonged periods
- If you have to stand for a long time, use a footstool
- Use cushioned shoes whenever possible
- Do not spend long periods of time looking down
- Position yourself correctly at your computer
- Sleep on a firm mattress
- Be aware that most injuries are cumulative
- Be fit!!! Exercise
- Stay trim
- Stay flexible
- Reduce stress
- Consult a physician if you feel you may have an injury