North American Risk Management, Inc. Loss Control

OFFICE ERGONOMICS

Greatest emphasis is placed on the phenomena of cumulative trauma disorders (CTD's), which basically are injuries brought about by repetitious activities of the hands, wrists, forearms, and upper body. Another term (used by OSHA) for these kinds of injuries is musculoskeletal disorder (MSD). Although there are other possible ergonomic situations, we'll be dealing with the office computer, also known as the Video Display Terminal (VDT) worker.

There are other aspects to office ergonomics, however, that can both interact with CTD type problems, or create "stand-alone" problems. These include such factors as lighting, computer screen glare, ambient work area conditions such as temperature / heat, background noise, and others. An example of interaction might be a worker, who is trying to avoid eyestrain from glare, holding her body at a strange angle, causing her to improperly bend her wrists, leading to wrist pain.

CARPAL TUNNEL SYNDROME CONTROVERSY:
Carpal Tunnel Syndrome (CTS) is a malady of the wrists, caused when swollen wrist tendons press against the median nerve which runs through the wrist. A structure of ligament and bone (called the carpal tunnel) limits the space into which the tendons can swell, and when swollen tendons press hard against the median nerve, numbness, tingling, inability to grasp, pain, and other symptoms appear in the hands. It is a serious condition that requires aggressive treatment, sometimes including surgery, to alleviate. In most cases, CTS is preceded by a history of pain and discomfort of the forearm and wrist tendons. Usually, true CTS only appears after a fairly long history of neglecting wrist and forearm pain. For an excellent, plain-language, non-medical discussion of CTS, click on this link.

Study findings of Danish researchers published in the June 11 issue of The Journal of the American Medical Association suggest that computer use is not associated with risk of developing CTS. This appears to contradict what has been "common knowledge" for quite some time-that computer keyboarding and mousing can lead to CTS.

This is a link to an abstract of the study.

Actually, in our experience, the study's conclusions are consistent with what we normally find in office ergonomics consultations. What we find is that although true Carpal Tunnel Syndrome is fairly rare, wrist and forearm tendon pain and tenderness are not at all rare. For some reason, in most individuals, this pain and discomfort does not seem to progress to full-blown CTS, while in others, it does. Some clinicians have suggested it may be a function of the individual's physical carpal tunnel size: some individuals have larger tunnels, therefore pressure on the median nerve is not as severe, so true CTS does not develop. We should be quick to add that in many cases, the definition of Carpal Tunnel Syndrome is not clear; we have seen supposedly professional medical personnel diagnoses of CTS, which were not true CTS. One other point we feel is significant; as we have found in our consultations, the Danish researchers found that mouse use increases occurrence of CTS somewhat.

It is our opinion that this study has some flaws; it was a voluntary questionnaire, the study group was limited to a specialized group, among others, however, we feel the greatest danger is that this study might lead a manager or business owner to discount all worker reports of pain or discomfort, leading to deterioration of the workers' conditions, plus condemning the workers to having to endure needless pain and discomfort.

Bottom line is, yes, computer-related CTS may be rare, perhaps even more rare than earlier believed, however, other discomfort and pain caused by improper postures, work stations, and similar factors associated with workplace computer use is very real, and needs to be dealt with, as does any factor that affects worker's health and safety.

THE FORMULA FOR CUMULATIVE TRAUMA DISORDERS:

CTD's occur when the following factors are present:

Exertion or Force
+
Repetition
+
"Problem Postures"
+
Insufficient Recovery (rest) Time

While this formula holds for all Ergonomic-related CTD's we'll be examining them from an office standpoint.

Exertion or force means any muscular exertion, including shoulder, hand, wrist, and finger movements necessary to manipulate a keyboard and mouse. Repetition refers to the repeated application of the exertion or force, in the same way, over extended periods of time. While some minor adjustments may be made in the force component, generally, there is not much that can be done about force and repetition in an office ergonomics situation. Problem postures, sometimes referred to a "awkward postures" is a different matter. In most cases, this is the factor about which the most can be done. Studies have produced a body of known "optimal" postures for all the body parts, which can be checked in the field, and usually adjusted. Likewise, it has been found that relatively short breaks can help reduce stress and pain considerably, if they're taken frequently enough. A minimum 5-minute break every hour is recommended, in addition to traditional mid-morning, lunch, and mid-afternoon breaks.

FINDING AND CORRECTING THE PROBLEM:

When a worker complains of wrist or forearm pain (often reporting it as "Carpal Tunnel Syndrome"), it most often results from the combination of the factors discussed above. Usually, fully correcting only one of them, or improving as many as possible, will bring about significant relief, if not full remedy. There are systematic, organized steps that can be taken to compare the workers' entire work area, habits, equipment, and other factors against known standards, so it can be seen what falls outside the norm, and may need to be improved.

Recent OSHA efforts in ergonomics have produced some good, useful tools that can be used in ergonomics evaluations:

This link is a good general-purpose checklist for evaluating workstations.

This checklist provides some suggested ranges for various workstation set-ups and measurements.

Here are some additional links to help you understand the various terms, measurements, and provide other information for you.

This link provides an overview of workstation considerations, and you can access other topics from this page.

Seating selection, setups, and adjustment for comfort are covered here.

Keyboards and mouse considerations are covered in this page.

NOTE 1: It has been our experience that for individuals who are already suffering pain or discomfort of their "mousing" hand / arm, that providing an ergonomic trackball [rather than the type shown on this page] often helps alleviate the symptoms, by removing the static loading of the arm necessary to manipulate a standard mouse. An ergonomic trackball is one roughly kidney-shaped, which fits into the palm and fingers of the hand as the hand rests on the desk or keyboard tray surface.

NOTE 2: Our consultants have also found that providing ergonomic, "split" keyboards, which are called "alternative keyboards" in this page, frequently help alleviate discomfort and pain symptoms are also well received. But, be ready for a "learning" curve while getting used to these kinds of keyboards, there is a difference in using them, and for a while, typing speed will drop, and typing errors will increase. Our experience is that this process takes 1-2 weeks at most, and users then just won't part with their new keyboards ! A detailed study of "alternative keyboards" prepared by NIOSH, is available here.

This link will discuss placement and adjustment of monitors and document holders. Generally, if a good deal of keyboarding is to be done from paper documents, it is very advantageous to provide document holders that can be placed immediately adjacent to the monitor screen, as shown in this page.

Administrative issues, such as breaks, production requirements, and other controls are discussed here.

Note: A key, and extremely important point made on this page is the concept of adjustability; even if a workstation is adjusted to perfect, optimum dimensions for an individual, a concentrated, long workday with no change in posture will produce adverse effects. Workers need to be able to adjust their workstations for a variety of positions, so static loading does not occur.

TWO FUNDAMENTALS FOR CONTROLLING CUMULATIVE TRAUMA DISORDERS:

1. Flexibility of the workstation, and the work..
2. Adjustability-the more adjustable each component of the workstation is, the better.

ADDITIONAL FACTORS:

The following two links deal with lighting in general, and glare, both of which can affect MSD's , but are also important considerations in and of themselves.

(Note: Individual files can be downloaded by right clicking on link and choosing "Save Target As". Files require Acrobat Reader to view, which can be downloaded for free by clicking on icon .)






		OFFICE ERGONOMICS Greatest emphasis is placed on the phenomena of cumulative trauma disorders (CTD's), which basically are injuries brought about by repetitious activities of the hands, wrists, forearms, and upper body. Another term (used by OSHA) for these kinds of injuries is musculoskeletal disorder (MSD). Although there are other possible ergonomic situations, we'll be dealing with the office computer, also known as the Video Display Terminal (VDT) worker. There are other aspects to office ergonomics, however, that can both interact with CTD type problems, or create "stand-alone" problems. These include such factors as lighting, computer screen glare, ambient work area conditions such as temperature / heat, background noise, and others. An example of interaction might be a worker, who is trying to avoid eyestrain from glare, holding her body at a strange angle, causing her to improperly bend her wrists, leading to wrist pain. CARPAL TUNNEL SYNDROME CONTROVERSY: Carpal Tunnel Syndrome (CTS) is a malady of the wrists, caused when swollen wrist tendons press against the median nerve which runs through the wrist. A structure of ligament and bone (called the carpal tunnel) limits the space into which the tendons can swell, and when swollen tendons press hard against the median nerve, numbness, tingling, inability to grasp, pain, and other symptoms appear in the hands. It is a serious condition that requires aggressive treatment, sometimes including surgery, to alleviate. In most cases, CTS is preceded by a history of pain and discomfort of the forearm and wrist tendons. Usually, true CTS only appears after a fairly long history of neglecting wrist and forearm pain. For an excellent, plain-language, non-medical discussion of CTS, click on this link. Study findings of Danish researchers published in the June 11 issue of The Journal of the American Medical Association suggest that computer use is not associated with risk of developing CTS. This appears to contradict what has been "common knowledge" for quite some time-that computer keyboarding and mousing can lead to CTS. This is a link to an abstract of the study. Actually, in our experience, the study's conclusions are consistent with what we normally find in office ergonomics consultations. What we find is that although true Carpal Tunnel Syndrome is fairly rare, wrist and forearm tendon pain and tenderness are not at all rare. For some reason, in most individuals, this pain and discomfort does not seem to progress to full-blown CTS, while in others, it does. Some clinicians have suggested it may be a function of the individual's physical carpal tunnel size: some individuals have larger tunnels, therefore pressure on the median nerve is not as severe, so true CTS does not develop. We should be quick to add that in many cases, the definition of Carpal Tunnel Syndrome is not clear; we have seen supposedly professional medical personnel diagnoses of CTS, which were not true CTS. One other point we feel is significant; as we have found in our consultations, the Danish researchers found that mouse use increases occurrence of CTS somewhat. It is our opinion that this study has some flaws; it was a voluntary questionnaire, the study group was limited to a specialized group, among others, however, we feel the greatest danger is that this study might lead a manager or business owner to discount all worker reports of pain or discomfort, leading to deterioration of the workers' conditions, plus condemning the workers to having to endure needless pain and discomfort. Bottom line is, yes, computer-related CTS may be rare, perhaps even more rare than earlier believed, however, other discomfort and pain caused by improper postures, work stations, and similar factors associated with workplace computer use is very real, and needs to be dealt with, as does any factor that affects worker's health and safety. THE FORMULA FOR CUMULATIVE TRAUMA DISORDERS: CTD's occur when the following factors are present: Exertion or Force + Repetition + "Problem Postures" + Insufficient Recovery (rest) Time While this formula holds for all Ergonomic-related CTD's we'll be examining them from an office standpoint. Exertion or force means any muscular exertion, including shoulder, hand, wrist, and finger movements necessary to manipulate a keyboard and mouse. Repetition refers to the repeated application of the exertion or force, in the same way, over extended periods of time. While some minor adjustments may be made in the force component, generally, there is not much that can be done about force and repetition in an office ergonomics situation. Problem postures, sometimes referred to a "awkward postures" is a different matter. In most cases, this is the factor about which the most can be done. Studies have produced a body of known "optimal" postures for all the body parts, which can be checked in the field, and usually adjusted. Likewise, it has been found that relatively short breaks can help reduce stress and pain considerably, if they're taken frequently enough. A minimum 5-minute break every hour is recommended, in addition to traditional mid-morning, lunch, and mid-afternoon breaks. FINDING AND CORRECTING THE PROBLEM: When a worker complains of wrist or forearm pain (often reporting it as "Carpal Tunnel Syndrome"), it most often results from the combination of the factors discussed above. Usually, fully correcting only one of them, or improving as many as possible, will bring about significant relief, if not full remedy. There are systematic, organized steps that can be taken to compare the workers' entire work area, habits, equipment, and other factors against known standards, so it can be seen what falls outside the norm, and may need to be improved. Recent OSHA efforts in ergonomics have produced some good, useful tools that can be used in ergonomics evaluations: This link is a good general-purpose checklist for evaluating workstations. This checklist provides some suggested ranges for various workstation set-ups and measurements. Here are some additional links to help you understand the various terms, measurements, and provide other information for you. This link provides an overview of workstation considerations, and you can access other topics from this page. Seating selection, setups, and adjustment for comfort are covered here. Keyboards and mouse considerations are covered in this page. NOTE 1: It has been our experience that for individuals who are already suffering pain or discomfort of their "mousing" hand / arm, that providing an ergonomic trackball [rather than the type shown on this page] often helps alleviate the symptoms, by removing the static loading of the arm necessary to manipulate a standard mouse. An ergonomic trackball is one roughly kidney-shaped, which fits into the palm and fingers of the hand as the hand rests on the desk or keyboard tray surface. NOTE 2: Our consultants have also found that providing ergonomic, "split" keyboards, which are called "alternative keyboards" in this page, frequently help alleviate discomfort and pain symptoms are also well received. But, be ready for a "learning" curve while getting used to these kinds of keyboards, there is a difference in using them, and for a while, typing speed will drop, and typing errors will increase. Our experience is that this process takes 1-2 weeks at most, and users then just won't part with their new keyboards ! A detailed study of "alternative keyboards" prepared by NIOSH, is available here. This link will discuss placement and adjustment of monitors and document holders. Generally, if a good deal of keyboarding is to be done from paper documents, it is very advantageous to provide document holders that can be placed immediately adjacent to the monitor screen, as shown in this page. Administrative issues, such as breaks, production requirements, and other controls are discussed here. Note: A key, and extremely important point made on this page is the concept of adjustability; even if a workstation is adjusted to perfect, optimum dimensions for an individual, a concentrated, long workday with no change in posture will produce adverse effects. Workers need to be able to adjust their workstations for a variety of positions, so static loading does not occur. TWO FUNDAMENTALS FOR CONTROLLING CUMULATIVE TRAUMA DISORDERS: 1. Flexibility of the workstation, and the work.. 2. Adjustability-the more adjustable each component of the workstation is, the better. ADDITIONAL FACTORS: The following two links deal with lighting in general, and glare, both of which can affect MSD's , but are also important considerations in and of themselves. Ergonomics--Workstation Lighting Ergonomics-Screen Glare The following two links deal with lighting in general, and glare, both of which can affect MSD's , but are also important considerations in and of themselves. Back to Top (Note: Individual files can be downloaded by right clicking on link and choosing "Save Target As". Files require Acrobat Reader to view, which can be downloaded for free by clicking on icon .)