Static Grip Force Risk Factor in Computer Workstations When Using the Mouse
Conventional mice design requires that you 'grip' or 'pinch' the sides of the mouse in order to be able to accurately move the mouse to achieve functional, precise cursor movement. If an individual uses their mouse for only brief periods without intensity, this temporary non-neutral posture and muscle exertion probably will not cause any long-term hand condition. One cause for even casual users to develop problems is that even during periods of inactivity, people forget to take their hand off the mouse which means they continue to exert this 'static grip force' even when they are not actively targeting the cursor or clicking the buttons. Of course, for any user who intensively uses the mouse for even an hour a day, or users who regularly perform mousing activities throughout the day, the cumulative pinching force necessary to grip a mouse can lead to serious hand problems. In extreme cases this can lead to a 'death grip' on the mouse, i.e. the situation where the static grip behaviour has become so entrenched that the user is now maintaining an excessive grip on the mouse out of habit. This will also often lead to a user's involuntary gripping or pinching of the fingers, even when not using a mouse or pointing device. Clearly, static grip force is a problem with pointing devices that needs to be reduced or eliminated entirely for users to prevent the risk of injury over the long term.
Several kinds of pointing devices have been designed with the goal of eliminating static grip. Some pointing devices are designed to be 'gripped' more by gravity than by pinching force; others eliminate any kind of 'gripping' by being used in a stationary position while the user manipulates the pointing mechanism by fingers alone (e.g. a touchpad). While designs may vary from device to device, the underlying idea is to eliminate pinching force altogether. Constant pinching force overdevelops the flexor muscles in the hand, and unless there is something to balance this constant exertion (i.e. by using of the extensor muscles to 'open up' the hand an equal amount), this static grip force must be minimized if the user is to avoid developing conditions like 'death grip'. In today's workplace, it is no longer acceptable to ignore such basic things as a user's comfort and health - particularly when ignoring these signs adversely affects not only the well-being of the individual but also their morale and performance.
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