or Working with the Hands 'Flat' on the
What is Pronation?
Pronation refers to the twisting of the hand and forearm to a
fully 'palm down' orientation. When the hands and forearms
of an individual are flat on a desk they are working at, they
have fully 'pronated' their hands and forearms. This
position is not the neutral, relaxed posture of the hands when
performing an immediate task (i.e. working on a conventional
'flat' keyboard or 'flat' mouse when at a desk). For most
individuals, the posture that is most comfortable is somewhere
between 10° from the horizontal (i.e. with the thumb side of the
hand higher than the little finger) and a vertical or
'handshake' position (i.e. 90° from the horizontal). Every
individual has a different range and size of comfortable
postures that arises from their own physiology, conditions and
injuries they have sustained.
Why is Excessive Pronation a Risk Factor?
When an individual is forcing his hands to pronate to maintain
in full contact with the input device, this puts a static load
and strain on the joints, muscles and membranes in the arm which
can lead to fatigue, discomfort, pain and injury. Just as
excessive pronation is something that individuals seeking to
reduce the risk of injury should avoid, excessive Supination
can be an equally significant risk factor.
What is the 'Best' Angle to Position the Hand and Forearm?
As indicated earlier, every individual is unique and for some, a
near vertical posture will be most comfortable while for others
a near horizontal posture will be ideal. Unfortunately,
there is no 'best' angle, and there are multiple considerations
as what may be the best angle for the elbow may not be for other
muscle groups (e.g. the fingers). For keyboarding, the
tradeoffs of increasing the angle beyond 20° typically make this
the maximum viable angle to ideally position the keyboard for
most users (see Why
Does Vertical Mousing have Less Drawbacks than Vertical
). For mousing, there are less tradeoffs
in moving to a more vertical posture, which makes many mice up
to 30° viable options for many users.
How can a Keyboard Help to Reduce Pronation?
Keyboards which have a profile or design that allows the keys to
be physically higher in the center will result in a posture
which is less pronated (commonly called a 'thumbs up' posture,
as the thumbs are now higher above the work surface than the
little fingers). Adjustable
which offer the ability to 'tent' or incline to
the desired angle of the user will greatly assist in the
prevention of excessive pronation while keyboarding. Some
also have a non-adjustable fixed
inclination which, if it happens to be the angle the user is
seeking and meets their other needs, would also serve this
How can a Mouse Help to Reduce Pronation?
Mice which have a profile or design that allows, encourages
or forces the hand to be physically higher at the index finger
than on the little finger will result in a posture which is less
pronated. Typically these designs almost always provide a
specific location for the thumb which allows it to comfortably
rest at an almost vertical posture when compared to the other
always include a less pronated posture to provide
proper support and be orthopedically neutral.
What Other Equipment can be used to Reduce Pronation?
A simple 'do-it-yourself' solution is to create a mousing
surface which is inclined to the outside of the body to reduce
pronation in the mousing hand. Some Mousing
incorporate this into their design.
However, changing the mouse itself is a more effective solution,
and there is no way to reduce pronation when keyboarding if one
is using a conventional keyboard, unless the individual is
willing to saw their keyboard in half and re-solder all the
connections to make it functional again.