How to Choose a Good Ergonomic Mouse.

Did you know that 1 in 6 workers is suffering from some form of RSI or Carpal Tunnel Syndrome? These are conditions that, in the ergonomic industry, are widely associated with overuse of a poorly designed computer mouse. This can lead to people spending weeks or even months out of work and, in worst case scenarios, can require operations to resolve.

There is an easier alternative to developing these problems though – use a good ergonomic mouse. This begs the question, however, of how one identifies a ‘good’ ergonomic mouse. To answer that question, we first need to look at a regular mouse and the design problems that cause mouse pain to begin with.

Regular computer mice are designed in such a way as to make you grip them. (see image below) While this may seem normal, it is these very gripping and pinching actions that lead to RSI and Carpal Tunnel Syndrome developing. This is because the actions are being done all day, often 5 or 6 days a week, with the muscles getting little or no rest. On top of this, we often leave see people hovering over the mouse switches on conventional mice, adding to the muscle tension and cramped nature of the hand posture.
Another common issue with regular mice is the angle of the hand during the use of a computer mouse. We have two main bones in our forearm, Ulna and Radius, with a membrane connecting the two. To help prevent mouse pain, it is important that the blood flow through this membrane is as unobstructed as possible, and the angle of the hand on the mouse is key to this. To optimise the blood flow, the hand needs to be in the “natural position”. If the hand is twisted to far in one direction or another, the blood flow becomes restricted and problems can ensue.

The last problem worth mentioning is the development of rough/irritated patches of skin around the wrist area. These often develop due to the rubbing of the wrist against the desk during mouse use. Because the skin there is quite thin, with the bone quite close to the surface, it is an easy area of the body to irritate. While this is sometimes considered a minor issue compared to the big problems like RSI and Carpal Tunnel, it is easily preventable.

If the above causes mouse pain, then an ideal ergonomic mouse would do the following:

  1. Prevent any gripping and pinching – you shouldn’t have to/be able to hold on to the mouse to move it.
  2. The hand should rest on the mouse in a neutral position – all research concludes the hand should sit at an angle of between 25 and 30 degrees.
  3. The hand and arm should be supported in places where the body and tissue are biologically designed to support the weight – the membrane of the palm and the fatty tissue on the underside of the forearm are good for this.

The HandShoe Mouse is an example of the only ergonomic mouse currently on the market that was designed off the back of peer reviewed university research. The above factors, and many more, were all considered during the design of this mouse. The resulting design, when tested in the tax offices in The Netherlands was that every member of staff that was out of work with mouse complaints were able to come back into work again while working with the mouse.

Although it can be time consuming to find, there is a great deal of research supporting very specific ergonomic mouse designs. Much of this research can be found on our publications page (https://handshoemouse.com/publications/) and is largely third-party material.  

Assessment of the Musculoskeletal Load of the Trapezius and Deltoid Muscles during Hand Activity

deltoid muscle

Stabilization of Hand Required for High Precision Tasks

During fundamental research and field research we noted the significance of a relaxed hand and forearm to operate a computer mouse. Gripping and pinching as well as reaching for the mouse showed to have severe negative effects on the upper extremity.

We require our hands to perform a great number of varying tasks with the mouse which requires high precision. Although Professor Van Zwieten, Department of Anatomy, BioMed, University of Hasselt mentions the possible risk of moving from the wrist in his paper “Hand Positions in scrolling, as related to PC-workers’ dystonia and treatment of dystonia by means of vibrostimulation and external shock waves therapy” (2009) we sometimes have to.

Danuta Roman-Liu, et al.

Higher precision requires stabilization of hand and forearm to minimize stress. It is from this perspective that we are pleased to be able to refer to the paper by Danuta Roman-Liu, et al. Department of Ergonomics, Central Institute for Labour Protection, Warsaw, Poland.

“Assessment of the musculoskeletal load of the trapezius and deltoid muscles during hand activity.” (2001). In this publication the following is mentioned:

First, higher precision of a task in which only the hand is involved, requires accuracy of movements which means more stabilization of the upper extremity and thus higher muscle tension. Furthermore, in view of the difficulty and possibly the complexity of the task a higher muscular tension can be expected.

No Effect on the Deltoid Muscle

Where is the Deltoid muscle?

The resulting muscle loads due to the performed task influences the tension of the trapezius muscle. Contrary to what is generally thought the study proves that there is no effect on the deltoid muscle.

It should be noted that the lower the level of force used, the more precise a difficult task can be executed. As a consequence, when the forearm is not supported, a higher tension of the descending part of the trapezius muscle results. We herewith refer to the paper by Professor Han Ming Chen of National Taiwan University “The effect on forearm and shoulder muscle activity in using different slanted computer mice” (2007) and our team of Erasmus University Medical Centre “Result of the use of a hand supporting computer mouse by patients with neck and shoulder complaints” (2006).

Support the forearm

So this publication proves the need to support the forearm when working with a computer mouse.

Hand Support when using a computer mouse

 

“Action Is Reaction”: The Impact on your Computer Mouse

Author: Drs. ing. Paul C. Helder

One of the major rules of physics is action is reaction.
This brings me to the following point.
You most likely have been working with a regular mouse or “so called” ergonomic one for quite some time.
One of the phenomena you must have noticed is that the muscles in your forearm get tired. Let me explain.

There are hardly any muscles in your hands – just a group of so-called small hand muscles. The major ones which control gripping and pinching of fingers etc. are situated in your forearm. It is only their tendons which run into your hand and to your fingers.

These tendons therefore have to move through a guide, one of which is the Carpal Tunnel, the other one is Guyon’s Canal.

Chain Reaction and Carpal Tunnel Syndrome

The chain reaction we activate by deliberately gripping anything like a pen or a door handle, but also a regular mouse, has a significant effect on our upper body. This action force even reaches our deep neck muscles.
Please be aware that emotional stress may also have similar effects.

lymphatic flow
costaclavicular gate near neck

The strain in the deep neck muscles has a rather negative effect, for these muscles are also connected to the first rib.
By straining them we exert tension which can even lift the first rib.

During laboratory research we noticed that this has a negative effect on both arterial flow and nerves. Why? Because the first rib and clavicle bone are positioned above each other and thereby create a gate through which arteries, veins and nerves run.

So it makes sense that when we strain for example by gripping and pinching, we cause a pinching action in this gate. As a result you can get cold and or numb fingers.

The above mentioned flow restriction backwards to the heart also has a pinching effect on tendons running through the Carpal Tunnel.

How to Prevent Stresses and Strains

All in all, it is obvious that we have to prevent unnecessary stresses and strains.

One of the easiest ways to prevent excessive muscle tension in the forearm is neither to grip and pinch nor to hover the fingers above the mouse buttons. Thus we prevent the chain reaction which affects the deep neck muscles.

In an earlier blog post I already mentioned the negative effect of keyboard trays. These force the arm to hover and thus also instigate this chain reaction which results in strain in the neck and Trapezius muscles.

That’s why we advise to support the forearm. Preferably ¾ of the forearm on the desk, hand on the HandShoe Mouse and ¼ up to the elbow, free from the desk. This to allow easy movement of the hand with the mouse using the support point of the forearm as hinge pin.

Of course a good arm rest will also do.
See quotation Prof. Chen (bulged part rolling laterally on the desk led).

During our fundamental and field research which resulted in the development of the HandShoe Mouse, we noticed the significant impact of the above mentioned forces.
Because in general one is concentrated on the job i.e. controlling cursor and mouse and typing, one forgets all about the physical discomforts this instigates.
Only after work, when one relaxes, we start noticing this.

The above research resulted in a design which directs all grip forces to the palm of the hand, thereby preventing unnecessary reaction forces in the fingers and a fully relaxed thumb.

Please be aware, your muscles take time to fully relax and cure from gripping and pinching due to working with a conventional mouse. So you have to have a bit of patience when you start working with the HandShoe Mouse to experience its positive effects.

We therefore appreciate the following remark of a HandShoe Mouse user:

“I just want you to know that I really like this mouse and I definitely want to keep using one.
It has helped me with my hand, wrist, and arm issues.”