An Ergonomic Evaluation of the Kinesis Computer Keyboard


1. Introduction

In this information-technology age, everyday tasks are more and more
related to computer. That ranges from basic jobs such as providing food recipes
for housewives to complicated ones such as analyzing laboratory experimental
data for scientists and engineers. This popularity of computer means that the
time one has to spend with computer would be a lot more than in the past. Until
now, the computers and computer peripherals in the market have been made
according to the same design as the ones invented decades ago when computers are
used only in large-scale scientific projects or big corporations. That means
for most people the ergonomic value of these products obviously was not taken
into account when designing them. Fortunately, at the moment, more companies
are trying to change the way people work with computer by marketing a number of
ergonomic products most notably keyboard, mouse and monitor. There are
ergonomic keyboards, mice and monitors being released all the time. The reason
why the focus is on these products is that they are the parts of computer one
interfaces with the most while working with computer. The subject of whether
these ergonomic keyboards, mice, monitors and other products really work
attracts a lot of regular computer users. Thus, studies dedicated to it have
been done. This report is based on one of the studies about an ergonomic
keyboard from a manufacturer called Kinesis. This study looks not only on the
effect of the keyboard on the users\' body by mean of electromyographic activity
but also on the learning rate of the users changing to this new style of
keyboard. This is very useful since slow learning rate would lead to the
decrease in effectiveness of work. Introduced in 1868 by Christopher Sholes,
computer keyboard is still the primary data entry mode for most computer users.
With the increase of computer, hence keyboard, usage at the moment, these
problems of the keyboard users known as operator stress problems have developed.
This is a kind of cumulative trauma disorders which is mainly caused by working
excessively or repetitively with the same thing, keyboard, in this case, in the
same position for a long period of time. This kind of disorder is considered to
be the most expensive and severe one occurring in office environment. This leads
to an amount of alternative designs introduced in the market with the main
intention of reducing muscular stress required for typing. The reason why these
designs have not yet replaced the old one is because of the familiarity of the
users to the old design. This means an amount of retraining time is required to
familiarize the users to a new design of keyboard and thus the one requiring
less time is likely to be the choice. This study main objectives are to measure
and analyze initial learning rate and electromyographic activity, explained
later, while using an alternative design of keyboard, the Kinesis Ergonomic
Computer Keyboard (figure1.) These data are then used to compare to the
standard computer keyboard, the old design, to see if it is worth the time and
money spent on the new product. The electromyographic signals used to examine
the muscle activities in this study are signals generated by muscles. These
signals can sometimes be used to control artificial body limbs especially ones
requiring sensitive or complicated degree of control such as rotary or grasping
motion. Systems that use such signals are called myoelectric systems. The
Kinesis keyboard utilizes the same QWERTY layout as the standard design so that
users do not have to relearn typing all over again. The key ergonomic features
of this keyboard are: - The distance between centers of the halves of the
Kinesis keyboard is approximately 27 cm, reducing the angle of adduction of the
wrists to near zero for most adults. - The keypads slope downward from inside to
outside edge, and are concave to better fit the natural shape of the operator\'s
hands. The keys form straight columns and slightly curved rows. - The keyboard
features a built-in forearm-wrist support extending approximately 14 cm from the
home row to the edge. - The keyboard features separate thumb-operated keypads to
redistribute the workload from the little fingers to the thumbs. These keypads
consists of the enter, space, backspace, delete and combination (ctrl and alt)
keys. - Detachable numeric/cursor pad. - Integral palm supports. - Shorter reach
for function keys.

Figure 1. The Kinesis Ergonomic Computer Keyboard.

2. Details

2.1 Materials and methods

There were 6 female professional typists participants of age 29 to 52 and
typing experience of 10 to 32 years