Static Grip Force When Using the Mouse
What is Static Grip Force?
Static Grip Force refers to the requirement imposed by
conventional mice on the individual to maintain a constant pinch
force or grip force on the mouse in order to control and direct
the mouse and perform mousing operations. This arises due
to the symmetrical design of traditional mice and also the
reality that they are usually not Orthopedic
which are sculpted or sized to support the bone
structures and muscle systems of the hand. By failing to
take into account the anatomy of the hand, individuals are
forced to maintain a steady pinch grip force on the sides of the
mouse in order to be able to accurately move the mouse and
achieve precise cursor movement. This distorts the normal
neutral, relaxed hand posture to an awkward one which affords
sufficient control of the mouse. Due to common poor
behaviors, individuals will maintain this grip and exertion even
when not actively targeting or using the mouse, resulting in far
more strain and fatigue than one would otherwise expect to arise
from a high effort task.
Why is Static Grip Force a Risk Factor?
When an individual is required to force their hands to maintain
full control of the mouse, this puts a static load and strain on
the joints, muscles and membranes in the hand, wrist and arm
which can lead to fatigue, discomfort, pain and injury.
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 risk factor with pointing devices that needs to be reduced or
eliminated entirely for users to prevent the risk of injury over
the long term.
How Much Static Grip Force (or Pinch Force) is 'OK' and not a
Every individual has different degrees of strength, dexterity,
endurance and fatigue rates in the muscles in their hands.
For most individuals, anything other than a minimal amount of
pinch or grip force can cause fatigue and pain in the muscles if
the action is continually performed over an extended period of
time (e.g. gripping the mouse even while not actively using the
mouse through the workday). If an individual uses their
mouse for only brief periods without intensity, this temporary
non-neutral posture and muscle exertion may not cause any
long-term hand condition. However, as noted earlier, the
failure to remove the hand from the mouse significantly extends
the period. Any user who intensively uses the mouse for
even an hour a day, or users who regularly perform mousing
activities throughout the day should be aware of this risk
the Symptoms of 'Too Much' Static Grip Force?
When a user has to use 'too much' Static Grip Force, the flexor
of the hand (that one uses to make a
'fist') will be overused and create a strength unbalance
(relative to the use of the extensor muscles
which are used to open the hand). Typically the pain will
be throughout the hand and wrist and radiate up the
forearm. The localizations are most commonly in the
underside of the hand under the thumb (thenar eminence
the top or back of the hand (transverse carpal ligament
or the underside of the forearm either at the wrist (flexor
) or about 2-4" up from the wrist (flexor
). Typically the pain is a
burning constant pain, without pulses or significant variance.
What is 'Death Grip'?
A subsequent more serious condition which can arise from
Static Grip Force is 'Death Grip'. This refers to the
situation where many users continue to maintain a viselike grip
on their mouse even during periods of inactivity to the point
where the user's hands never get a chance to rest. Exacerbating
this is the reality that most users tend to grip the mouse
harder than is required in order to increase the feeling of
control while working, enough to 'kill' a regular living mouse,
thus the term 'Death Grip'
How can the Choice of Mouse Help to Reduce Static Grip Force?
are orthopedically sized and sculpted and can reduce
or eliminate the need and even the possibility of static grip
force while using a mouse by relying upon gravity and the
profile to provide control without a requirement of grip
force. Other types of pointing devices such as Central
take away the source of grip force, by using a different
paradigm for mousing and removing the cause (grasping an object)
from the action of mousing.
What Other Strategies can be used to Reduce Static Grip
A simple do-it-yourself solution is to take the hand off the
mouse when not actively mousing, which greatly reduces the
amount of time spent gripping the mouse. This will ensure
that the hand is only grasping a non-ergonomic mouse when