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

 

The Benefits of Using a HandShoe Mouse

With more and more people interacting with touchscreen devices rather than traditional computing inputs, you might be forgiven for thinking that the era of the mouse and keyboard is over. Even Microsoft has decided to embrace tactile displays, with Windows 8 doing away with the Start menu and turning its primary interface into a touch-friendly, tiled affair.

However, millions of people still need computer mice in order to interact with their PCs and there are plenty of different options on the market, from the basic to the specialist. The HandShoe mouse falls into the latter category, setting out to offer users the most ergonomic pointing experience on the market thanks to its fluid, intuitive design that, as the name suggests, fits your hand like a shoe fits your foot.

Using a mouse all day every day can leave you with more than just sore joints; you might also develop serious disorders like carpal tunnel syndrome, or a repetitive strain injury. This is because the standard design of a mouse is not all that ergonomic, requiring that you hold your hand in an unnatural position for an extended period, thus perpetuating these issues.

handshoe mouse benefitsThe imperfect design of mice also means that when you hold them, your fingers will often be hovering over the buttons while you grip the unit from the side. This means that your hand and arm are never at rest and this tension can build up over time and do you damage.

The HandShoe mouse has been created in order to combat the issues associated with standard pointing devices, with the design based on research conducted by a Dutch medical university.

The mouse itself is large enough to rest your entire palm on its surface, while your fingers and thumb will fall naturally into a comfortable position while still giving you access to all of the buttons typically found on this kind of device.

The idea is that your hand and wrist will be provided with support and the shape of the mouse, which has been awarded a patent, will not require any of the usual gripping or pinching which can be the root of physical problems caused by traditional mice.

Choice of Three Sizes

The HandShoe mouse does not take a one size fits all approach. Instead there is a choice of three sizes that accommodate people with small, medium or large hands.

There are of course other mouse devices out there that claim to be ergonomically designed, but few can match up to the HandShoe mouse when it comes to the quality of the experience. If you have to spend all day at a PC and do not believe that the touch screen revolution is going to trickle down to standard desktop machines for some time, this product could offer you the relief you require.

You can always use mobile phone contracts to get your fill of touchscreen interaction and then take advantage of the HandShoe mouse when you are at the office or in your den at home.

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.