Research Study - Ergonomic Test of the Kinesis Contoured Keyboard - 2

Stimuli
The test stimuli consisted of pages of double-spaced lines of text and five groups of five lines of seven random capital letters (see Appendix A). The stimuli pages were placed on a document holder located to the left side of the computer display.

Equipment
The following equipment was used to present stimuli, monitor keying performance, record hand and upper body position, and EMG activity, and to perform data analysis. The ISO reference (traditional) keyboard was an AST KB101 keyboard with an angle of 5 degrees, a key field angle of 8 degrees, and a home row height of 30 mm with no palm rest; the test keyboard was the Kinesis Ergonomic Keyboard,.Model 100.

A Precision Biometrics Inc. MyoVision 4000 instrument and software package was used to collect and analyze EMG activity. The software was installed on a Hewlett-Packard Vectra PC - RS/20.

Two Sony DXC-930 video cameras recorded subject posture. One was located directly above the subject and recorded the upper body posture so that any deviation of the hands and the elbows from a neutral position could be recorded and later measured. The other camera, located at the side of the subject, recorded vertical angulation of the right hand. A Panasonic WJ-MX50 Switcher allowed the superimposition of the video image from one camera onto a section of the image from the other camera.

Subjects' keying activity was recorded onto a JVC BR-S822U video tape deck in a S(Super)-VHS format. Time and date stamping were incorporated on the video images, via a Panasonic WY-KBS0 Character Generator. Audio instructions ("start, stop and break time") to subjects. comments from subjects, and comments from test observers, were recorded via JVC MI-3000 audio board.

A Hewlett-Packard Vectra PC was used to analyze keying performance.

TAB Products computer terminal tables with adjustable keyboard trays and ergonomic chairs were used for subject's workstations. The environmental conditions (temperature, humidity and illumination) were set to ISO test specifications.

Procedure
The study was conducted in the GET usability lab. Each subject participated in the study for three days at the same time each day, either in the morning or in the afternoon. At the beginning of the first day, each subject was briefed about the test and asked to complete Kinesis questionnaire (see Appendix B). The subjects were asked to adjust their chairs to a preferred comfortable position. The keyboard height was then adjusted to an ergonomically correct position at the preferred chair height.

Electrodes were next placed on eleven of the subjects at four locations on the forearm and at one location on the upper arm to monitor the muscle activity levels of ulnar deviation, extension, pronation, and arm abduction. A ground electrode was attached to the neck of each subject. Table 1 shows the names of the muscles, activity controlled by these muscles, and assignment of the electrode to an EMG channel.

Each subject was tested on the two keyboards at the same time on two different days. Each subject practiced keying on the Kinesis keyboard for seven hours the day before they were tested on it. Keyboard assignment was altered between subjects to provide for balanced experimental design (see Table 2).

The keying tasks consisted of typing text for four 20-minute sessions and then typing random letters for two 20-minute sessions on each keyboard. Each subject was given 5-minute break at the end of each 20-minute session, and 15-minute break between the third and fourth sessions (see Table 3). The subjects were instructed to turn each page when they completed keying the page. Each subject was instructed to use the left hand to turn the page in order not to interfere with muscle activity monitoring of the right hand.

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