Repetitive Strain Injuries -The Same Old Story

Repetitive Strain Injuries – The Same Old Story

By: Guest author Izzy Woods

Your grandparents must have told you dozens of stories about how they used to write with a pen before the great upgrade arrived – the typewriter. What they will never tell you is the problems typewriters caused for users even before electric models came in.

Repetitive strain injuries have been around for decades, but many didn’t know what the pain was and what caused it. To give an example; if you typed 60 words per minute and worked just a six hour day – so you still took your lunch break – you’d have typed around 18,000 key strokes each hour. Each movement required 8 ounces of pressure which equates to 54,000 pounds being pressed by fingers attached to sore wrists.

27 Tons of Arm Pressure

This is the equivalent of 27 tons of pressure being applied to your hand muscles each day. And remember, there was no delete button back then so if you made a mistake, you probably had to start all over again.

repetitive strain injuries

The addition of electricity reduced the amount of pressure needed to type, but you still had to keep your hands in the same position all day long so you could type faster – more words each minute. Then came the computer and then the mouse.

Instead of moving ten fingers around the keyboard, we now moved to one position on the right of the keyboard, even if you were left handed. (Left handed mice came much later.) Yes, you still typed with one or both hands, but most movements had to fit around the mouse.

Then the mouse evolved. Many different styles, sizes and so called ergonomic options became available, but they still didn’t address the main problem – the need for the wrist to remain in one place for hours at a time and more significantly, at the wrong angle when you need to apply pressure.

Government Reports

The U.S. department of Labor, Occupational Safety and Health Administration (OSHA) tells us that repetitive strain injury is the country’s most widespread and expensive health problem. The difficulty affects hundreds of thousands of workers across the U.S. with a price tag estimated at more than $20 billion each year in compensation for workers.

Almost two-thirds of all occupational illnesses relate to the wrist, elbow or shoulder. The most usual injury is carpal tunnel syndrome. The words are so well known these days that the medical term doesn’t need explaining.

OSHA reported that repetitive motions, like gripping tools, scanning groceries and typing, caused the longest nonappearances from occupations. On average the time away could last up to 23 days. There are so many carpal tunnel injuries that surgeons now report that repair is the second most common hospital procedure.

repetitive strain injuries

And the problem is likely to get worse as we spend more time at our desks. After a full day at work, you rush to turn your home computer on and either surf or play games for hours on end until it’s time to go back to work again. Most games on computers are played via the mouse. So is there a solution to the problem?



A Change in Style

Perhaps there is. The Handshoe mouse is one of the most advanced solutions to enable you to handle your computer work without strain. Available in both left and right hand versions (because, in case you haven’t noticed, our hands are different) it has a new design that helps people with RSI back to work much quicker.

One of the key aspects of the mouse is a rest for the thumb, which is an alternative to gripping the mouse with the thumb while getting it ready to click for web navigation. Maybe this mouse will help you use the computer more comfortably and will get people out of the reclining chair and back to work.

More information about repetitive strain injuries on this HandShoe Mouse blog.


Latest Research: Vertical Mouse Needs Re-evalution

vertical mouse

When people are talking about the best ergonomic mouse, we frequently hear remarks about the so called “Handshake” position, alleged to be the most natural and relaxed. This statement is then substantiated by means of a picture or video in which a skeleton is used.
To our judgment this is an aberration, for, we as human beings can only act and do as we do because of physical functions for which we need muscles, tendons, blood, arteries, veins, nerves etc. By leaving out these higly significant elements of the acting human body, one gets a most unrealistic if not ridiculous impression.

Continuing Ergonomic Research

At both Erasmus (Rotterdam, Netherlands) and Hasselt (Belgium) University Medical Centers, highly educated researchers continue to study the human body, based on corpses, to simulate the situation in a working environment. This has also taken place for the position of forearm and hand while operating a computer mouse.

The first point to be made is that there is a fibrous sheet (membrane) which connects the 2 bones (Ulna and Radius) of the forearm. Rotating the forearm like when you put your hand on the desktop has a significant effect on this membrane. Next to this phenomenon one should not forget that a number of muscles which control the fingers are connected to this membrane.
In studies, the behaviour of this membrane has been looked at to establish the effects of for example a position like the “handshake”.

Truly neutral hand position on an ergonomic mouse is not vertical but slanted

Recent research by Professor K.J. van Zwieten and his team of the University of Hasselt (Belgium), demonstrated that the Handshake position results in a maximally taut membrane between the 2 bones, Ulna and Radius. Therefore the need to grip and pinch a mouse in a Handshake position, for example with a vertical mouse results in unnecessary strains in the already taut membrane. This could possibly result in physical complaints. In two publications, the resesarchers have stated that the use of a vertical PC-mouse in Handshake positions should therefore be re-evaluated.(see publication 1 and publication 2)

The studies with regard to the design of the computer mouse by Professor Han Ming Chen of National Taiwan University and Professor Snijders of Erasamus University Medical Center are of significant interest.
Erasmus University has already shown that the ElectroMyoGram (EMG) measurements of a vertical mouse show a continuous activity without any moment of rest, just like a standard computer mouse.

EMG ergonomic mouse



ergonomic mouse

This, among others, is the result of the reaction force of the thumb with respect to the fingers, not only due to holding the mouse (gripping and pinching) but even more when switching.
By means of EMG measurements it is shown that a slightly slanted mouse body (like the HandShoe Mouse) prevents the above mentioned unnecessary tensions.

One must therefore assume that the truly neutral hand position on an ergonomic mouse is not vertical but slanted.

Repetitive Strain Injury May Come Back Within Hours

RSI potential

It is a well known fact that muscles in your hand and arm get used to all sorts of actions and positions.
This of course applies specifically to the standard mouse which is generally too small for your hand. It forces your hand and fingers in an awkward position to be able to hold onto the mouse. For example thumb and little finger have to  grip the mouse while the other 3 fingers sort of hang over the mouse, this to prevent inadvertent switching. Not only is this position of the hand uncomfortable, it results in excessive muscle tension with detrimental effects. One of the first signs is pain in and around the wrist and around the upper part of the forearm, the elbow. When you continue working like this, these stresses can even result in pain in shoulders and neck. (Ref.

Therefore the Erasmus University Medical Center, looked at the possibility to relieve the computer mouse user of these unnecessary stresses and strains. During the initial fundamental research professor Chris Snijders and drs. ing. Paul Helder showed that a good hand support could reduce or even eliminate these unnecessary muscle forces. The subsequent field study substantiated this.
We are proud to mention that during EMG measurements with the Medical Faculty of the University of Maastricht it was shown that our assumptions were correct.
Now, after a number of years, having gained experience with the HandShoe Mouse, we are of the opinion that this truly ergonomic mouse provides the necessary relief to reduce the risk of RSI complaints to a minimum.

Always Use Your Ergonomic Mouse At home Too

For example, a number of HandShoe Mouse users state, that when using another, conventional mouse at home, while using the HandShoe Mouse in the office, the aforementioned stresses and strains in hands and fingers immediately re-occur.
That’s why we advise to take the HandShoe Mouse with you and use it everywhere you work with PC or laptop. The HandShoe Mouse cable, which is an industry standard cable, can easily be disconnected from the mouse. And if you have a spare cable at home, you can simply connect the HandShoe Mouse to your home PC. If you use a wireless HandShoe Mouse version, make sure you also bring the dongle (micro receiver) which takes care of the communication between mouse and computer.
Thus it is very easy to connect the mouse when you have cables connected to the various work stations you use.