“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.”