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Home Forums General Ergonomics Topics Good or Bad?-arm supports such as arm-boards, metamorphosis board versus desktop-worksurface

This topic contains 10 replies, has 10 voices, and was last updated by  mmyhre1 12 years, 3 months ago.

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  • #36989

    [private user]
    Participant

    I’ve mostly followed the practice of educating and training computer workers not to lean on the worksurface, armrests, or wristrest while working.  Either a keyboard tray is provided or the worksurface height is adjusted with the keyboard and mouse positioned at the front edge of the desk, closest to the end user, to promote relaxed arm position and "floating".

    However, a 2006 article co-authored by David Rempel, published in the British Journal of Occupational and Environmental Medicine and a recent seminar I attended encourages full forearm support.  Dr. Rempel disputed any risks to the nerves or circulatory compression or postural issues.

    "the study shows that use of large arm boards significantly reduces neck and shoulder pain as well as hand, wrist and forearm pain."

    Fellow Ergonomist, is it now more acceptable or common practice to support the forearms on a worksurface area?

    #39239

    [email protected]
    Participant

    Excellent question. I know the efficacy of resting the arms/forearms has been discussed behind the scenes for years, and I’m glad to see some evidence based research appearing.

    That being said, I’ll share my own anecdotal experience with using a board. Several years ago I started experiencing right shoulder and neck discomfort on my mousing side. I often modify my work area while testing new products, so I don’t recall the specifics of the set-up other than I was reaching too far forward for my mouse at the time. I installed a board (the Butterfly Board, which I don’t think is commercially available any more). It was wide and deep, slanted at about 10 degrees toward me, and had a semi-circular pocket cut-out at the front. It also had a pad that covered areas where the bony parts of my arm could rest. I was able to type and use my mouse at what would normally be extended arm postures, all the while resting my elbow/arm/forearms. Shoulder discomfort gone, and no new discomforts associated with the board. Long story short, it’s one of the most comfortable and effective workstation arrangements I have ever experienced. I think the primary reason is that it supported a reclined seating posture (leaning back), and most other equipment and arrangements don’t.

    Peter Budnick, PhD, CPE
    Ergoweb Inc.

    #39434

    Rick Goggins
    Participant

    After seeing a number of computer users who had pushed their keyboards back so that they could rest their forearms on the worksurface and reviewing the research on forearm support, I’ve started recommending this practice as an acceptable alternative.

    I caution the users to avoid reaching too far forward or elevating their arms too much, and recommend a wrist rest to help reduce wrist extension. I also make sure that they’re resting on the "meaty" part of the forearm, not on the flexor tendons or the elbow.

    I would be cautious about recommending arm boards that created a lot of positive tilt, especially if it places the hands above the heart, for circulatory reasons. A modest amount of positive tilt might help correct the bad habit of leaning forward that some computer users seem to develop.

    Rick Goggins, CPE
    Washington State Department of Labor and Industries
    Olympia, Washington

    #39244

    [private user]
    Participant

    Great discussion- daily I am challenged with individuals who state that they feel more comfortable resting their forearms on the desktop when working.  I try and encourage them to work from a keyboard tray, but some individuals just can’t get comfortable using one. 
    I caution the employee about contact stress and how it can impair circulation, nerve conduction, while also placing more stress on muscles of the UE. We have definately  seen our share of employees who have obvious symptoms from contact stress.  For this reason, I almost always advise employees against resting their elbows on their armrests while they work or on the desktop.
    On the other hand,  I have had to deal with individuals who are dealing with neck, shoulder and upper arm pain and have benefited from an arm support when working at the computer. 
    We have had great luck with the Ergorest.  It cups the forearm and pivots to move with you while you work.  It is padded, and also can be "fine tuned" to fit each individual.  I have always wondered if it is not a better solution for more individuals that work at the computer all day, but do not necessarily have a medical need.  ??

    Anne Duggins, MA, OTR/L

    #39272

    Ankrum
    Participant

    Arne Aaras did some studies years ago and found that resting the forearms significantly reduced stress on the neck.

    If users insist that a particular method is better for them, they are usually right. If that does not fit with our theories, it’s more often that the theories need to be changed.

    Denny Ankrum 

    #39319

    kshanfield
    Participant

    I also find that it is nice to give folks options. I do recomend if they are going to rest their arms on the desktop to support their forearms while typing, that they adjust their chairs a little higher than if they were to use a keyboard drawer. This keeps them from or hiking or flexing the shoulders to reach the keyboard. Sometimes this adjustment requires the user to use a footrest.  I also LOVE the Ergorest arm supports and find they solve many problems for both prevention and supporting an injured arm.

    #40677

    JayLBrand
    Participant

    Great conversation!  Based on a recent review of this literature, I found that there is surprising support for resting the forearms on a desksurface to prevent neck, back or shoulder pain.  However, we need to adopt a systems perspective, because steps taken to prevent pain or eliminate risks for one body part/segment frequently increase pain or risk in another body part/segment.

    I believe that (broad) forearm support is preferable to wrist or elbow support–both of which have long-term problems.  A chair with 360-degree rotating arms can be a great chair if adjusted and used properly to support the forearms while keying with the arms hanging loosely "floating" at the sides.  Of course, the keyboard still needs to be close enough, and low enough, for the user to key comfortably with their arms in that posture.

    But yes, options and frequent adjustments over time are also a good idea. 

    My review:
    Brand, J.L. (2008). Office ergonomics: Pertinent research and recent developments (pp. 245-281). In C.M. Carswell (Ed.), Reviews of human factors and ergonomics, Vol. 4. Santa Monica: Human Factors and Ergonomics Society.

    Jay L. Brand, Ph.D.
    Cognitive Psychologist
    Haworth Holland, Michigan
    616.835.1481

    #39289

    [private user]
    Participant

    As a clinician treating only industrial injuries in onsite clinics,for 25 years, the abscence of contact with work surfaces, wrist rests or chair arm rests is critical to prevention of carpal tunnel and elbow tendinitis.  When clients arrive with carpal tunnel symptoms of all severities, worksite observation routinely includes contact between underside of wrist and or forearm with worksurfaces, arm rests, or wrist rests.  When keyboard trays elbow height keyboard/mousing surfaces are provided and employees instructed to key and mouse with arms free of contact of any kind, symptoms are routinely, consistently abolished.

    Our employees/patients are instructed to rest their hands on the 5th finger side, palms facing inward when editing, waiting for screen changes etc.  This can be done in the lap or on wrist rests.  Wrist rests are not recommended for the mouse as it pushes the mouse 2" away creating a reach and increased tendency to rest on mousing surface.  The challenge is to learn to hold hands up (as in playing the piano) while keying or mousing.

    The biggest payoff is the dramatic reduction in injury rates for computer users.  Employers and employees are happy!

    #39297

    JayLBrand
    Participant

    This discrepancy between the suggestions of a researcher based on a few limited studies and the experience of a practitioner who cannot ignore his/her personal observations is one of many reasons why I called for a systems perspective to move our discipline forward (in the review previously referenced).

    I realize systems theory is not new, but it apparently does not inform very much of the research investigating risk factors for and/or preventive strategies regarding WRMSD’s.  To empirically decide the issue raised here requires studies that measure neck, shoulder, back, wrist, hand, finger, elbow AND forearm symptoms–and perhaps symptoms from the hips, buttocks, legs and feet AS WELL (at least for seated work).  We can’t continue to provide single independent-variable, single-dependent variable studies and expect to retain credibility among practitioners.

    Such narrow research approaches lead to ridiculous suggestions like ignoring circulatory, ligament and nerve problems (in the elbows, forearms and hands) in favor of reducing neck, shoulder & back pain by allowing employees to rest their forearms or hands on hard or sharp-edged desk surfaces for extended periods of time while keying.  That’s ludicrous–and I don’t mean the music group . . .

    Jay L. Brand, Ph.D.
    Cognitive Psychologist
    Haworth Holland, Michigan
    616.835.1481

    #39304

    admin
    Keymaster

    Based on some of the research presented at the Marconi Cf on office ergonomics several years ago I began to consistently use adjustable pivot arms combined with either a negative tilt keyboard tray or if the worker could be positioned higher and had preferences not to use a tray – allowed them as above – to work with arms resting on the work surface – as I am an in house ergonomist I can follow up with all inidviduals at any time in the future and I would certianly say that using this approach had more success in my experience than removing arms of chairs in the past – saying that – if the arms are not pivoting and not height adjustable – I find they simply add to the issue

    Debbie Schwartzentruber
    Manager of Ergonomics
    Maple Leaf Consumer Foods Canada
    Canadian Certified Professional Ergonomist

    #40680

    mmyhre1
    Participant

    This issue has been explored in depth and I find the ergonomists with engineering or cognitive background prefer arm supports and those with a therapy background tend to find they are not beneficial.  Initially I recommended arm supports when it was warrented with the idea of unweighting the arms and therefore providing relief of the shoulders and neck.  However, further in my practice I saw more adverse effects from those that used supports.  Supports generally limit motion and localize the movement to smaller muscle groups.  The jobs where these are recommended are already sedentary with limited motion and that is not beneficial to the body as we know.  The supports reduce this more.  I also found frequently the supports pulled the shoulders  into a more protracted position – more work required and harder on the joint, and the head in a more forward position which can have negative consequences to the neck and innervation to the arms.  Also I started to see more ulnar nerve compression in the workplace and I can’t recall ever seeing this in my PT practice.  These were all related to resting the elbow on the arm rest or desk.  There is a place for supports but with caution to ensure proper posture is maintained, motion isn’t reduce too significantly and there is no compression or pressure points created.

    Marnie Myhre, MS, PT, CEA

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