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.
2.1 Materials and methods
There were 6 female professional typists participants of age 29 to 52 and typing experience of 10 to 32 years involved in this experiment. Typing speed in words per minute, typing accuracy in percentage of characters typed correctl