Ergonomics

Ergonomics

Last updated December 14, 2007 11:47 AM

Ergonomic injuries represent the fastest growing category of injuries in the United States today. They are now the leading cause of Workers’ Compensation claims, and even unreported cases are accompanied by pain, loss of function, and the potential for permanent disability.

Carnegie Mellon has a strong pro-active ergonomics program, and hundreds of employees and students have benefited from either attending a training class or having an evaluation of their worksite. If you would like to attend a training class or if you have any suggestions that you think may enhance the program, contact us at 8-8182.

To schedule an evaluation, you may register on-line here.

The Occupational Safety and Health Administration (OSHA) has not yet established an ergonomics standard, although one was in place briefly before it was rescinded by Congress. OSHA has made ergonomics a high priority, so there is little doubt that a standard will eventually be passed. If you would like to learn the status of OSHA’s ergonomics activities, go to the OSHA web page. The National Institute for Occupational Safety and Health (NIOSH) also has an excellent web site that posts regular updates on ergonomics.

Ergonomic injuries may be referred to as Repetitive Stress Injuries (RSI’s), Musculoskeletal Disorders (MSD’s), Cumulative Trauma Injuries (CTI’s), or Cumulative Trauma Disorders (CTD’s). Because OSHA and NIOSH generally use the terminology Musculoskeletal Disorders, EH&S also uses that term in the interest of consistency.

Symptoms of Muskoskeletal Disorders (MSD's)

Common Muskoskeletal Disorders (MSD's)

Risk Factors

Employee/Student Involvement

Work Station Layouts

Ergonomic Training

Desk Exercises

Symptoms of Musculoskeletal Disorders (MSD’s)

Symptoms of musculoskeletal disorders and other ergonomic injuries may be subtle at first, leading the individual to ignore them. Following are the most common symptoms that may be experienced:

Pain in the fingers, wrists, or other parts of the body (this may range from a stabbing type of pain to a dull ache)

Tingling or numbness, particularly in the hands or fingers

Swelling, inflammation, or deformity

Loss of muscle function

Discomfort or pain in the shoulders, neck, or upper or lower back

A burning sensation in the arms or hands

Extremities turning white or feeling unusually cold, indicating possible nerve or circulatory problems

General feeling of stiffness or cramping

A loss of gripping strength, or pain when making a fist

Reduced range of motion

Discomfort when making certain movements

These symptoms may be alerting you to any of several types of ergonomic injuries. NEVER ignore these symptoms. Call EH&S (8-8182) for an evaluation and seek medical intervention.

Common Musculoskeletal Disorders

The previously mentioned symptoms may signify the presence of any of several MSD’s. These injuries affect the joints, tendons, muscles, ligaments, and other parts of the body. Accurate diagnosis is best left to a medical professional, but may include any of the following:

Carpal Tunnel Syndrome

Tendonitis

Tenosynovitis

Bursitis

Raynaud’s Phenomenon

DeQuervain’s Disease

Back and neck disorders

Trigger Finger

Sciatica

“Housemaid’s” Knee

Vibration Syndrome

Rotator Cuff Syndrome

Reporting Ergonomic Injuries

As with any injury, it is important that you report your MSD at the first sign of discomfort. Even the slightest pain should be viewed as a warning sign. Failure to get medical intervention can lead to even further discomfort, lost work days, or even permanent disability. Your symptoms may be very innocent, but they may also be warning you of potential ergonomic problems.

Reporting your injury is easy and can be done with minimal effort. The Supervisor’s Injury and Illness Report requires your supervisor to make an evaluation and analysis of your accident, but it has the advantage of getting your complaint on written record. This provides financial protection for you should there be a need for medical treatment or worker’s compensation.

Risk Factors

While anyone can incur an ergonomic injury, there are a number of known risk factors which increase the potential. If your job exposes you to any of the following, contact EH&S to learn how you can reduce your potential for injury:

A high number of repetitions – This is the most common risk factor encountered at Carnegie Mellon and is usually associated with concentrated computer use. If you repeat the same motions every few seconds, or if you use a keyboard and mouse for several hours each day, you increase your susceptibility to an MSD. The faster you perform these repetitions (e.g., typing fast) and the more force you use (e.g., hitting the keyboard with a heavy touch), the greater your chance of incurring an ergonomic injury.

Force – Increased typing speed is usually accompanied by an increased stroking pressure. This can lead to finger, hand and wrist injuries. Lifting heavy weights is another form of force which leads to MSD’s, usually in the lower back area. Lifting is affected not only by the weight of the object being lifted but also by such factors as body position, type of grip, irregular weight distribution of the object, and the duration of the task. Lifting heavy objects several times (i.e., force combined with a high number of repetitions) is a recipe for incurring an MSD. Contact EH&S for advice on lifting, or plan to attend one of our classes on Lifting/Back Safety.

Awkward postures – This can occur in any of several jobs on campus: Researchers leaning over a microscope, FMS relampers or painters working with their arms over their heads for extended periods of time, secretaries leaning over a file drawer without adequate breaks, or anyone bending or kneeling are examples of jobs which are susceptible to this type of injury.

Contact Stress – This refers to any activity that requires you to make physical contact with an object which may place excess pressure on nerves or blood vessels. Resting your elbows on a lab bench all day or using your hand as a hammer are examples of contact stress. This type of injury can occur over an extended period of time or it may happen immediately.

Vibration – Any job which requires you to use vibrating tools can lead to nerve damage. FMS employees are the people most susceptible to this type of injury, which can occur due to extended use of chain saws, power tools, lawn mowers, leaf blowers, or other similar devices.

Employee/Student Involvement

All employees are encouraged to participate in the Ergonomics Program, and suggestions for ways to improve it are always welcome. Students, while not covered by OSHA regulations unless they are working students, are also encouraged to participate. Ways to participate include, but are not limited to:

Reporting MSD symptoms

Requesting work station evaluations

Completing feedback reports following evaluations

Checking out and viewing ergonomic videos from the EH&S video library

Obtaining ergonomic brochures from EH&S at our office in the FMS Building, or at the annual Health Fair

Participating in training programs offered by EH&S

Requesting a speaker for your class, group, or department

Work Station Layouts

While employees are not required to order
ergonomic furniture or equip their office with ergonomically friendly equipment, it is encouraged. Guidelines are offered for the following:

Desks/Tables
Chairs
Monitors
Keyboard/Mouse
Body Position, Work Habits
General/Miscellaneous

Guidelines for Desks/Tables

Monitor and keyboard platforms should be independently adjustable. If this is not possible, the keyboard should be placed on a keyboard tray that can be adjusted for height, angle, and horizontal positioning.

Front edge (where keyboard would be placed) should not have any sharp edges.

Foot rests and wrist rests should be available.

Guidelines for Chairs

Chairs should be adjustable, including adjustment for the backrest, with an adjustable tilt and backrest angle.

Adjustments should be pneumatic or hydraulic, rather than mechanical, for height adjustment.

The backrest should be able to be locked into one position when desired.

The chair should have five legs for maximum stability, 360o swivel, and a waterfall, or rounded, front to minimize pressure on the underside of the legs.

The chair must have good back support. Seat tilt should move forward, as well as back, to provide back support if leaning toward the monitor.

Chairs should be equipped with armrests that are wide enough and soft enough that there is no unnecessary pressure imposed on the forearms.

The armrests should be adjustable, preferably in all directions.

Material should be non-sliding and breathable (no plastic or vinyl).

There should be a 1” – 3” clearance between the front edge of the seat pan and the back of your knees when you are sitting comfortably with your back against the backrest and your feet flat on the floor.

Guidelines for Monitors

Monitors should be adjustable for height and angle, to avoid neck discomfort and to control glare.

Placement should be directly in front of the user.

Monitors should be positioned so that light from windows comes in from the side. Overhead lights should run parallel with the computer user’s line of sight. (Where this conflicts with proper window positioning, it is usually easier to control window light with blinds, and the overhead lights become the condition for which monitor positioning is crucial).

Monitor elevation should be such that the eyes are directed to the top of the screen, or just slightly below, when looking straight ahead.

Keyboard/Mouse

The mouse should be sized so that it fits the user’s hand comfortably.

The mouse should be immediately beside and at the same level as the keyboard. Where keyboard trays are used the tray must be large enough to accommodate both the keyboard and the mouse..

Generally, the legs at the back of the keyboard should be kept retracted, to avoid excessive bending at the wrist.

Body Position and Work Habits

The mouse should be moved from one side to the other on a weekly basis, to maximize recovery times.

If soreness develops in hands or forearms, reduce typing speed. If there is no improvement within a few days, get an evaluation to determine if other factors are involved.

Chairs should be positioned so that there is a 90o angle at the knees and at the hips. Footrests should be available for those who can not meet these angles. Something as simple as a box may be used, although it should be replaced as it depresses.

Keyboards should be positioned so that there is a 90o angle at the elbows without shrugging the shoulders.

The chair, keyboard, and monitor should be placed directly in line with one another so that there is no neck rotation necessary to view the monitor.

Placing the monitor at the inside corner of two adjoining surfaces should be avoided unless accommodations are made for the keyboard and mouse.

Monitor screens should be kept clean and dust-free, to minimize glare.

Users can minimize eyestrain by remembering to blink regularly when working at the monitor, and by regularly (every few minutes) looking at a distant object for a few seconds to vary the eyes' focal lengths.

Desk exercises are helpful and recommended.

Computer users should work no longer than one hour at a time before taking a short (5 – 10 minutes) break. Break reminder software can be used if you have difficulty remembering when to interrupt your work routine. A free program can be downloaded from http://www.cheqsoft.com/break.html.

Wrists must be kept straight in both the horizontal direction and the vertical. It may be necessary to use a wrist rest to prevent the wrist from dropping below the neutral plane. However, do not rest your wrists on the rest continually.

General/Miscellaneous

Window blinds should be in place for control of glare and brightness.

Adjustment mechanisms must be fast and easy to activate, or they will not be used.

Small lamps, or task lighting, may be placed on desks to facilitate reading, but must be placed so that they do not produce screen glare.

If users will be doing a lot of typing from documents, manuscripts, etc., document holders should be used. They should be placed immediately beside the monitor so as to reduce head and neck movement.

At least a few of the work areas in multi-user offices should be wheelchair accessible. Adjustability will be especially important in these areas.

Ergonomic Training

EH&S offers regularly scheduled training classes in Office Ergonomics, Laboratory Ergonomics, and Lifting/Back Safety. Course descriptions may be viewed at the Training web page. CMU employees may register for any of these scheduled classes, or request that a class be set up for a group or department, by calling EH&S at 8-8182.

EH&S maintains a library of ergonomic videos which any CMU employee may check out by showing a valid CMU Identification Card and signing a checkout form. All employees are encouraged to take advantage of this free service, although it is not intended as a substitute for ergonomic training. The videos are to be used as a supplement to the regular training, as a means of refreshing memory, or as awareness training.

Newly hired employees will continue to be made aware of the ergonomics program at their Orientation Training. This also does not serve as a substitute for the more comprehensive ergonomics training regularly offered.

Student Health Services personnel provide training for all undergraduates and for all new graduate students.

Desk Exercises

Many ergonomic injuries can be prevented by simply stretching properly and warming up before beginning to work. These exercises can also be performed any time you have an interruption in your work cycle, planned or unplanned.

While the exercises we recommend are all low impact and require no special skills or equipment, you should consult your doctor before trying them if you have any type of ergonomic injury.

Desk exercises are offered for:

Thumbs

Fingers and Forearms

Wrists

Shoulders

Neck

Trunk and Back

Eyes

Questions?