RSI associated with specific keyboards

[Hypersphere]

Fortunately, during a rather long career at the computer keyboard, I have rarely been bothered by any sort of repetitive strain/stress injury (RSI), such as carpal tunnel syndrome. I have had ulnar nerve compression from resting my left elbow on a hard armrest on my office chair, and I have had "mouse shoulder" following a right shoulder injury from another cause, but both of these maladies have disappeared.

I have used a wide variety of keyboards with different form factors, layouts, and key switches. Among many others, these have mainly included the full-size IBM Model M, IBM SSK, IBM XT, HHKB Pro 2, and RF 87u 55g keyboards. For the most part, my use of these keyboards has been pain-free.

Recently, however, I have experienced pain in my left wrist after using my newest board, the RF 87u 55g; it seems to subside after returning to the HHKB Pro 2 for a while.

I never noticed any pain from any other keyboard, including others with Topre switches, such as the HHKB Pro 2.

There are two major differences between my two Topre-switch boards. The RF has plate-mounted switches that are 55g weight; the HHKB has case-mounted switches that are 45g weight. I suppose the problem could have arisen from either or both of these variables (or neither one; it could be coincidental and due to some other factor that I have not recognized).

Although I cannot prove this, the problem does not seem to be rooted in the difference in actuation force between the two boards. Instead, I suspect it is the abrupt bottoming-out encountered with the plate-mounted switches in the RF. In contrast, bottoming-out feels more springy or cushioned with the case-mounted switches in the HHKB Pro 2.

Has anyone else here experienced a similar problem? If so, what are your theories on what has caused the problem, and what solution(s) have you found, other than to stop typing?

Thanks.

[Muirium]

I'm thinking it's more to do with where you're resting your hands. Buckling spring is much more distinct than the weight and plate differences between your Topres.

[Hypersphere]

"Weight and plate" has a nice ring to it. If you google this, the first hits are all about steel plates for weight-training racks rather than keyboards, prompting the age-old question whenever any of my posts hint at physical weakness, "Do you even lift?"

Doyouevenlift.jpg (30.14 KiB) Viewed 3041 times

https://www.facebook.com/pages/Do-you-e ... 8019574345
In any event, I shall try to be more mindful about not resting my hands on surfaces while typing. Now that I am paying attention, I find that I have, in fact, been resting my left palm on the edge of the desk while typing on my RF. I will see if I have a similar tendency when typing on other keyboards.

[Muirium]

I'm a one man hapax legomenon. Minus the implied namespace availability…

But yeah, watch those wrists, and whatever contortions your fingers wind up playing. Could be that a 60% really is your best bet, for other reasons than simply size and style.

[Hypersphere]

Nice to be that singular outlier in a Zipfian distribution.

Regarding boards, perhaps we are misguided in wanting steel plates and no flex. An interesting example is the flexibility of the wings in the Boeing 787. Without the capacity to flex, the wings would snap off in flight.

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http://www.wired.com/2010/03/boeing-787 ... flex-test/

[DanielT]

I'm using a HHKB Pro2 as daily driver at work. My work consists in typing almost all of the time. No problems so far for me. Maybe it depends on the size of the hands, typing style, posture. My typing style is like nothing described, I'm all over the keyboard, part touch part look at the board, hard to train the muscle memory ...

[Hypersphere]

I'm using a HHKB Pro2 as daily driver at work. My work consists in typing almost all of the time. No problems so far for me. Maybe it depends on the size of the hands, typing style, posture. My typing style is like nothing described, I'm all over the keyboard, part touch part look at the board, hard to train the muscle memory ...

Your work pattern and typing style sound similar to mine. I've also had few problems over the years, with the exception of things with readily identifiable causes (for example, ulnar compression from an armrest; mouse shoulder after a shoulder injury).

It is known that wrist size is inversely correlated with the risk of developing carpal tunnel syndrome (CTS). Likewise, wrist misalignment along with repetitive trauma can give rise to CTS.

It does seem like the trauma component is more pronounced with the RF board, simply because there is less give to the board than there is with the more flexible HHKB Pro 2, and I tend to bottom out with every key stroke.

[pietergen]

You might experiment with a flexible mat (rubber mat or something) under your keyboard, to introduce some "give".

Another thought - maybe this is nonsense, but here it goes: could it be that the keycaps of that keyboard are stiffer in some way? Could different keycaps be beneficial ?

[Hypersphere]

You might experiment with a flexible mat (rubber mat or something) under your keyboard, to introduce some "give".

Another thought - maybe this is nonsense, but here it goes: could it be that the keycaps of that keyboard are stiffer in some way? Could different keycaps be beneficial ?

Thanks for the suggestions. I already have a Perixx DX-2000 extra large mouse pad under my keyboard and mouse. This doesn't provide much "give". The flexibility it does provide would be distributed over the entire keyboard rather than under each individual key, and I had been using this pad with all my keyboards, including the IBM XT and HHKB Pro 2 as well as more recently with the RF 87u 55g.

The keycaps should not provide much flexibility, either. In any case, I am using a keycap set from my HHKB Pro 2 on the RF 87u 55g, so that most of the keycaps are identical on the two boards.

The main differences between the two keyboards are (1) metal plate-mounted switches in the RF vs case-mounted switches in the HHKB; and (2) 55g switch weight in the RF vs 45g switch weight in the HHKB.

[bitemyweewee]

I read into this thread expecting there to be Star Citizen discussion (RSI Robert Space Industries).
I was wrong.
I have never had these problems with typing, I do however suffer from skin irritation on my forearms from flailing my mouse around, rubbing on the edge of my table and mouse pad.