Marks before the source URL indicates the main tone of the source in regard of wrist/palm rests:
[xy]
^^
|`--- opinion regarding palm rests
`--- opinion regarding wrist rests
-means "no, you shouldn't"~means neutral or non-conclusive opinion is given+means "yes, you can"
Examples:
[-~]means "don't use wrist rests; there's pros and cons to palm rests"[ +]means "nothing is said about wrist rests; palm rests are fine"
Wrist rest supports wrists: http://www.thegreenhead.com/imgs/loaf-bread-keyboard-wrist-rest-2.jpg
Palm rest supports palms: http://www.especiallyoffice.com/shop/contents/media/fellowes-gel-clear-keyboard-wrist-rest-purple-9183601-in-use.jpg
Not all authors distinguish between the two (and I can't blame them — wide enough rest can be considered to support both palms and wrists). When no distinction is made, I mark according to the wording used by the author (i.e. if the "palm rest" is mentioned, I mark the second column and leave the first one blank).
Most resources conclude that wrist and palm rests should only be used for resting and can't be used while typing. Some suggest that the rest can be used to "guide" your wrists/palms into the optimal position relative to the keyboard. Out of all the sources, the only one that looks like a decent scientific article suggests that wrist rest doesn't cause much difference in terms of muscle tension; it is noted that left hand bends a bit more without a palm rest, but not significantly.
Most of those aren't scientific articles. Next to none evidence is provided to support the claims. I would very much like to see links to actual scientific research in that domain (I'll certainly do another pass to inspect references).
I didn't read those in full, so I might have missed some important quotes. If you spot an omission, please report it to me.
Reference lists are given so that claims can be checked and further literature research conducted.
> Do not use a wrist rest. Research suggests that using a wrist rest
> doubles the pressure inside the carpal tunnel because the floor of the
> carpal tunnel is a more flexible ligament that transmits external
> pressures directly into the carpal tunnel.
References:
* Amick, B.C., Robertson, M.M., DeRango, K., Bazzani, L., Moore, A.,
Rooney, T., et al. (2003). Effect of office ergonomics intervention on
reducing musculoskeletal symptoms. Spine, 28, 2706–11.
* Delleman, NJ, Berndsen, MB. (2002). Touch-typing VDU operation:
workstation adjustment, working posture, and workers’ perceptions.
Ergonomics, 45(7): 514-535.
* Hedge, A. (2006). 10 tips for using a computer mouse. Retrieved December
1, 2006 from Cornell University Ergonomics Web,
http://ergo.human.cornell.edu/cumousetips.html.
* Hedge, A, Morimoto, S, Mccrobie, D. (1999). Effects of keyboard tray
geometry on upper body posture and comfort. Ergonomics, 42(10):
1333-1349.
* Jacobs, K., Johnson, P., Dennerlien, J., Peterson, D., Kaufman, J., Gold,
J., et al. (2008). University students’ notebook computer use. Submitted
for publication.
* McLean, L., Tingley, M., Scott, R.N., Rickards, J. (2001). Computer
terminal work and the benefit of microbreaks. Applied Ergonomics, 32,
225-237.
* Pentikis, J, Lopez, MS. (2002). Ergonomics evaluation of a government
office building. Work, 18(2): 123-131.
* Serina, E.R., Tal, R, Rempel, D. (1999). Wrist and forearm postures and
motions during typing. Ergonomics, 42(7): 938-951.
Adapted from Rachel Neuman’s “Tips Specific to Notebook Users.”
> Wrist rest
>
> ! Not always required
> " Depends on the individual
> ! May actually increase CT pressure
> ! Research suggests forearm support with wrist rest instead of for the wrists
> " Highly individual
> ! Should not be too bulky or hard
No references.
> Does a wristrest help? It is far better to move the keyboard and mouse
> right to near edge of the table and very close to your body so there is
> no space to rest your wrists at all. You are forced to relax your hands
> in your lap when not typing/mousing and forced to move the mouse with
> your entire arm. If this is not possible for some reason, or you cannot
> learn to break the habit of dropping your wrists when you are resting,
> there are a few wristrests which are soft enough not to cause serious
> compression of the nerves and limit blood supply in the wrist. You can
> see our recommendations on our wristrest webpage:
> http://working-well.org/pwristrst.html. If you have an old wristrest that
> is made of firm (or petrified) foam, please throw it out. Wristrests made
> of soft gel or beanbag materials are recommended if you must use a
> wristrest.
References:
1. Comparative Study of Two Computer Mouse Designs. Hedge, A., Muss, T.A.,
and Barrero, M. Unpublished report. July, 1999. Dept. of Design and
Environmental Analysis, Cornell University.
http://ergo.human.cornell.edu/Pub/HFlabReports/MouseRep.pdf
2. Can a more neutral position of the forearm when operating a computer
mouse reduce the pain level for VDU operators? Aaras, A., Dainoff, M.,
Ro, O., and Thoresen, M. International Journal of Industrial Ergonomics,
30(4-5), Oct., Nov. 2002, pp.307-324.
> Wrist rests are used to keep the wrists flat when the user is not typing
> or using the mouse. It is important not to drop wrists on the rest while
> typing.
No references.
[--] http://www.fss.txstate.edu/ehsrm/programs/occupational/ergo/contentParagraph/06/document/ergo_alt_kybds.pdf
> Bending the wrist back has been shown to reduce the diameter of the
> carpal tunnel, potentially increasing pressure on the median nerve. In
> addition, it causes some forearm muscles to work in a shortened form,
> which is an inefficient work mode increasing susceptibility to muscle
> fatigue.
>
> Two situations commonly involve backward-bent wrists. First, a user may
> drop his/her wrists to the work surface in order to rest them during
> typing. A wrist rest can help correct this by preventing the wrists from
> sagging.
>
> It's also possible to see backward-bent wrists when a keyboard is placed
> lower than elbow height. A low keyboard in itself is not a bad thing; in
> fact the available research indicates there may be advantages to working
> with partially straightened elbows. But a low keyboard slanted toward the
> user's face inevitably causes bent wrists. Flattening the slope of the
> keyboard or even sloping it back can induce a straighter wrist posture.
> This is the objective of support legs on the fronts of keyboards.
> Keyboards with built-in wrist or palm rests share the design intentions
> of keyboards with front support legs --- they attempt to encourage
> straight wrist postures that are considered to be comfortable, non-
> fatiguing, and possibly healthy. In addition, they help the user's wrists
> avoid the sharp, hard edges found on many keyboards and furniture.
> Built-in wrist rests have rarely been studied. However, there are a
> number of studies on generic wrist rests. In general, research supports
> the idea of resting the hands on some kind of a surface during keying
> pauses. The use of wrist rests has been associated with reduced muscle
> activity in the arms and shoulders, straighter wrist postures, comfort,
> and preference. Some research suggests that wrist rest users sit in a
> somewhat more reclined posture than people without wrist rests, which is
> known to be comfortable and healthy for the back.
>
> However, wrist rests are not without potential problems. Not all studies
> of wrist rests show positive effects. Recent research suggests that use
> of a wrist rest causes the fluid pressure in the carpal tunnel to rise,
> sometimes significantly. One study indicates that convex wrist rests,
> which concentrate pressure in a small area, are less desirable than
> broad, flat ones. And at least one report describes a benign cyst
> apparently caused by constant pressure on the wrist. Because of this
> information, ergonomists emphasize that users who wish to have a wrist
> rest should choose and use them carefully. Typists should use them during
> keying pauses, not during keying, in order to have free hand and arm
> movement and to reduce the amount of time the wrist is compressed.
No references.
[~ ] http://www.researchgate.net/publication/222571286_The_effect_of_wrist_rests_and_forearm_support_during_keyboard_and_mouse_use/file/79e4151087015cda56.pdf
> There were no significant differences for right wrist flexion/extension
> between use of a wrist rest and no wrist rest for keyboard or mouse use.
> Left wrist extension was significantly higher without a wrist rest than
> with a wrist rest during keyboard use […] No differences with respect to
> use of a wrist rest were found for the left or right hand for ulnar
> deviation for keyboard or mouse use. There were no differences in muscle
> activity between the test conditions for keyboard use.
There is a list of references, but nor abstract nor conclusion mention any
of them, so no list is presented here.
The document is short but informative, and well worth reading. The
conclusion, though, is this:
> BAD - Resting Your Wrists ( = Wrist Rest ) or Putting Any Type of
> Pressure on the Underside of your Wrist
>
> GOOD - Supporting Your Palms ( = Palm Support) which Reduces the
> Possibility of Wrist Extension and Reduced Blood Flow
No references.
> Palm rests are an alternative to wrist rests and are generally beneficial
> when wrist tendonitis structures are inflamed and/or sensitive to tactile
> stimulation.
> As consultants, we use wrist rests only after a significant ergonomics
> analysis has been performed. We have noted instances of wrist
> rests/supports being applied "across the board" which is not only
> ineffective, but often the cause of further problems.
> Our practical experience indicates the wrist support (when properly
> applied/specified) is a necessary and functional workstation component.
> However, it must be applied in view of full hand, wrist, arm aggregate and
> task performance analysis. Simply placing a piece of ergonomic labeled
> piece of rubber under painful wrists will do no good, and may make the
> problem worse. Even with a good wrist rest/support improper hand/wrist
> placement may still result in further/rapid biomechanical breakdown due to
> continuous compression of internal/neural wrist structures.
No references.
> We don't want to have anything in contact with the wrist itself while we
> are typing at a keyboard or controlling an input device, whether a mouse
> or a trackball. One of the worst things we can do is increase pressure on
> the wrist while we use our hands in this way. A more accurate term would
> be a "palm" rest, a point of view shared by increasing numbers of people
> involved in ergonomics.
> The most common mistake in the use of a palm rest is to plant the hands on
> it at all times when typing. This is a habit that is unfortunately
> encouraged by the many catalog photographs of people typing in this way.
> It's a "rest," and is intended for the times between actual keying.
No references.
[~ ] https://www.ergonomicsmadeeasy.com/pages/carpal-tunnel-syndrome/computer-workers-benefit-from-keyboard-wrist-rest
There's nothing specific to take from the article; it essentially says
"there's pros and cons to wrist rests".
No references.
> When your wrist is too low, even if it appears to only be a little bit
> low, the weight of the forearm falls into it. Many people use wrist rests
> to compensate, but they can actually worsen the problem because by resting
> your wrist on the wrist rest even a little, you’re still breaking the
> alignment of the hand and forearm. This will cause the weight of your arm
> to fall into the wrist, leaving your fingers unsupported and making it
> difficult for them to move. In other words, you’re still at risk for
> hurting yourself!
No references.
Apart from the quotes below, the article contains possible solutions to the
problems stated.
> When you rest on your wrist, you can compress the blood vessels, tendons,
> and nerves that travel through your wrist. But you may ask “isn’t it
> better to rest on the gel than on a hard desk?”. Not necessarily, because
> often the wrist rest padding is quite stiff, and the presence of the rest
> makes users think it is good to rest their wrist, so they tend to rest
> them more often. Resting your wrist for too long can potentially cause
> inflamed tendons and nerve entrapment.
> In order to reduce the risk of injury and discomfort, the proper way to
> move the mouse is with whole arm movements that originate at the shoulder.
> But an elevated wrist rest can get in the way of this. If you try to move
> your arm, your wrist drags across the wrist rest, so you cannot move the
> mouse efficiently. Instead, you plant your wrist and control your mouse
> with small wrist movements.
No references.
> Don't use a Wrist Rest - research has shown that using a wrist rest
> doubles the pressure inside the carpal tunnel, because the floor of the
> tunnel is a more flexible ligament that transmits external pressure
> changes directly into the carpal tunnel (the roof of the tunnel is bone so
> the pressure doesn't get transmitted on through the hand). Indeed, one
> test for carpal tunnel syndrome (CTS), know as Tinel's sign, simply
> involves tapping on the palmar surface of the wrist, which is enough to
> cause tingling and numbness in someone developing CTS.
No references.
> Much of the research that has been done on wrist rests has provided no
> clear indication that using wrist rests can help in the prevention of CTS.
> Additionally, many of the controversies surrounding wrist rests question
> whether they can alleviate discomfort, or worse, cause damage themselves
> when they are used improperly.
> The biggest mistake people make is leaving or pressing their wrists on the
> rest while typing, or even resting.
No references.
> Wrist rests can play an important role in wrist positioning for those
> using a keyboard or mouse. The goal is to have a neutral wrist (the wrist
> being flat and straight, not bent forward or back or angled to either
> side). A neutral wrist angle reduces stress and friction on the structures
> at the wrist and can help reduce discomfort and fatigue with typing and
> mousing activities.
> In spite of the misleading name, the wrist rest is not designed for
> resting the wrist while typing. The wrist rest should guide the wrist into
> a neutral position enabling the wrist to glide over the wrist rest while
> typing. The wrist should only actually touch down on the wrist rest during
> typing breaks. If the wrists are actually planted down on the wrist rest
> during typing, the small finger muscles are isolated causing awkward
> finger positioning and movements and creating muscular stress.
No references.
> There is a growing debate among ergonomic and occupational health experts
> over the actual need for a wrist rest to perform keyboard and computer
> mouse work safely. One school of thought suggests that wrist rests do help
> align the user's hands and wrists while typing or mousing, while another
> suggests that they may encourage users to relax their hand positions too
> much while typing. Instead of decreasing the number and severity of carpal
> tunnel injuries, an improperly used rest may actually cause more
> repetitive stress injuries (RSI) for those who type or mouse for extended
> periods of time.
> One of the main concerns about the use of a wrist rest, however, concerns
> the idea of the user resting his or her hands at all while actively typing
> or mousing. Proper typing technique stresses the importance of bending or
> cupping the hands in order for the fingers to strike the keys at a
> downward angle. If the user's wrists are resting on a pad while typing,
> the fingers must reach for the keys at a more stressful angle. For this
> reason, many occupational health experts suggest only using a keyboard or
> mouse wrist rest between typing and mousing sessions. The user's wrists
> should not touch the pad during active typing.
No references.
> Don't use wrist rests or armrests while typing-only while resting. If your
> workstation has wrist rests or armrests, be sure to use them only while
> taking breaks. Never use wrist rests or armrests while typing. A wrist
> rest should be used to rest the heel of your palm, not your wrist itself.
No references.