Ever wonder why right shoulder/arm & right shoulder/neck discomfort is the second most common complaint we quantify in our day to day consulting practice at OPC across Canada?
I am using photographs taken by our consultants which I would like you to have a look at. When you look at the photographs I would like you to keep one measurement in mind; the magic number of 15″.
Just imagine if we asked you to place your right arm at the same height and angle shown in the photo above and to keep it in this posture for most of the day (we will allow you to take breaks and your lunch break). How do you think your right shoulder and neck/shoulder will feel after just one day? Ask yourself is the hand holding the mouse in these photographs within a 15″ reach (measure from the right shoulder to the hand).
Here is what the appropriate reach envelope should look like when using the keyboard and mouse at your workstation:
Bearing in mind how much time people spend using the mouse, which started with the introduction of Windows technology in the 1990s coupled with the increased use of forms designed by your IT experts and software engineers, all of us are using the mouse with greater intensity. Placing the mouse within the 15″ reach zone depicted above is now even more important in preventing shoulder and shoulder/neck discomfort on the right side.
Despite this fact it is interesting to see that most keyboard trays (which should be sparingly recommended in very specific instances only- see my earlier blog about Standards for Keyboard Tray use) still keep the mouse section well outside of this 15″ reach envelope and also at a height which is different than the keyboard section itself.
The tray depicted above is made by most manufacturers such as HumanScale, Teknion, ISE to name a few. Despite our advice to manufacturers to no longer design keyboard trays like this, they continue to release these onto the market. The tray depicted above has the mouse section at greater than the 15″ reach envelope AND set at a different height than the keyboard section. The reach envelope for the right shoulder is breached thereby resulting in an ergonomic hazard for the neck and shoulder. Now you can see why your right shoulder/arm/neck is sore by the end of the day!
The Solution: Avoid using keyboard trays unless you are less than 5’1″ in height or taller than 6’1″ and your workstation height cannot be adjusted. Otherwise the trays cause issues such as limited leg room under the tray; incorrect reach and height to the mouse with the right arm (left if you are a lefty); increased reach and visual distances to items on your desk.
In this case make sure you keep the mouse as close to the keyboard as possible. If you find you still cannot keep the mouse within the 15″ reach envelope consider purchasing the short or left handed keyboards such as the GoldTouch or Kinesis (see my earlier Blog about these products). Another alternative is to replace your mouse with a large trackball such as the Kensington (never buy a trackball which uses your thumb to rotate it!)
And if a tray is indicated by your qualified Ergonomic Expert at OPC make sure the design is simply one length with room for the mouse at the same level and placed within a 15″ reach such as the one depicted in this photo (note how this design also allows Lefty’s to place the pointing device onto the left side of the keyboard if preferred);