Civil Engineering Reference
In-Depth Information
TABLE 39.3 Typing Speed Words Per Minute (WPM) and Accuracy (Backspace Strokes per
100 Typed Words) for Different Keyboards
Keyboard
Typing speed
Typing accuracy
Conventional
69.67 (19.61)
7.61 (4.09)
Goldtouch
58.92 (21.40)
11.38 (5.37)
Maltron
29.26 (8.86)
19.29 (5.88)
PST
62.37 (17.28)
8.39 (3.72)
Maltron keyboard represents an important impediment for its acceptance. Table 39.4 summarizes the
effect of alternative keyboard designs on the tested typing variables.
The current data demonstrate that after a relative short practice session typists were able to adjust their
posture, performing as well with some of the tested alternative keyboards as with the conventional key-
board. This study indicated that keyboard design had an important effect on typing in terms of musculos-
keletal diseases risk factors.
39.4.3 Training Effect on Typing on Ergonomic Keyboards
Immediate interests such as performance preservation and high training costs have delayed the introduc-
tion of ergonomic keyboard designs. In the literature there is a lack of data regarding the improvement in
typing parameters induced by subjects' adaptation to the new designs.
In an attempt to reduce the impact of extensive office work on CTD incidence, a wide variety of
alternative keyboard designs have been developed. Although previous studies noted an alleviation of
tendon travel, wrist deviation, and forearm pronation, when typing on alternative designs, urgent inter-
ests including replacement costs and early decreased performance deferred the introduction of alternative
keyboards. Also, dramatic design modifications caused unbending resistance from companies and data
entry personnel. Zacevic et al. (2000) noted that after 10 h of training, the decline in productivity was
10% for the FIXED keyboard (split angle of 12
8
and a lateral slope of 10
8
) and 20% for the OPEN key-
board (split angle of 15
) when compared to the standard keyboard. The
majority of studies included in their experimental design very short training sessions, leading to
biased outcomes. Swanson et al. (1999), in a study that assessed the impact of different keyboard
designs on performance and comfort, described typing performance for alternative keyboards as a
curve with an initial decline that is recuperated through the session.
In a study that determined the training effect on wrist posture and repetition, overall applied force,
typing performance in terms of number of typed words per minute and number of mistakes per 100
typed words, and EMG forearm muscles activity for two different ergonomic keyboards, Fagarasanu
et al. (2004c) noted important variations in studied typing variables. Twenty subjects underwent 8 h
of training on each of the alternative keyboards.
The typing speed was significantly improved by training. Typing speed improved by 48% for both
Goldtouch and Maltron keyboards. For the Goldtouch keyboard, the accuracy rate for the trained
8
and lateral inclination of 42
8
TABLE 39.4 Changes in Typing Parameters for the Tested Alternative Keyboards when Compared with the
Conventional Design
Wrist posture
Typing Performance
Wrist
Repetition
Applied
Force
Muscle
Activity
Keyboard
Ulnar deviation
Extension
Pm
Error Rate
PST
$
$
$
#
$
$
$
Goldtouch
#
$
$
#
$
$
$
Maltron
#
#
#
"
$
#
"
Note:
$
¼
no statistically significant difference;
#
¼
statistically significant decrease;
"
¼
statistically significant
increase.
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