An Analysis on the Effects of Different Types of Keyboards on Users’ Productivity and Hand Muscle Strain

Abstract

Musculoskeletal disorder (MSD) complaints are increasing as people are forced to do their daily tasks at home using computers, as evident with the limitations brought by the COVID-19 pandemic. The purpose of this study was to provide a comparative analysis on the efficacy of different types of keyboards in terms of typing speed, accuracy, and prevention of wrist/hand fatigue among keyboard operators to assist them in increasing work productivity and minimizing the risk of Carpal Tunnel Syndrome (CTS) or other hand injuries. To assess the pain level, typing speed, and accuracy, the participants were subjected to a 5-minute keyboard typing activity to test 4 different keyboards: standard, mechanical, foldable, and laptop. Through the Kruskal-Wallis H-Test, it has been found that mechanical keyboards are the optimal choice for all students and typing-related workers to increase their typing speed and accuracy and alleviate wrist/hand-related pain. Other than using a mechanical keyboard in the virtual workplace, it is also recommended that the users’ hands move freely and be elevated above the wrist rest while typing to enhance the wrist's mobility.

Full text

Ergonomics in Design, Vol. 47, 2022, 531–538
https://doi.org/10.54941/ahfe1001980
An Analysis on the Effects of Different
Types of Keyboards on Users’
Productivity and Hand Muscle Strain
Carlos Ignacio P. Lugay, Yoshiki B. Kurata,
Joseph Ramon M. Leofando, Janfil Mari M. Pamisal,
and Jeryl S. Salas
Department of Industrial Engineering, Faculty of Engineering,
University of Santo Tomas, Manila, Philippines
ABSTRACT
Musculoskeletal disorder (MSD) complaints are increasing as people are forced to do
their daily tasks at home using computers, as evident with the limitations brought
by the COVID-19 pandemic. The purpose of this study was to provide a comparative
analysis on the efficacy of different types of keyboards in terms of typing speed, accu-
racy, and prevention of wrist/hand fatigue among keyboard operators to assist them
in increasing work productivity and minimizing the risk of Carpal Tunnel Syndrome
(CTS) or other hand injuries. To assess the pain level, typing speed, and accuracy, the
participants were subjected to a 5-minute keyboard typing activity to test 4 different
keyboards: standard, mechanical, foldable, and laptop. Through the Kruskal-Wallis
H-Test, it has been found that mechanical keyboards are the optimal choice for all
students and typing-related workers to increase their typing speed and accuracy and
alleviate wrist/hand-related pain. Other than using a mechanical keyboard in the virtual
workplace, it is also recommended that the users’ hands move freely and be elevated
above the wrist rest while typing to enhance the wrist’s mobility.
Keywords: Keyboard design, Mechanical keyboard, Productivity, Ergonomics
INTRODUCTION
Carpal tunnel syndrome (CTS) is one of the most reported work-related
musculoskeletal disorders due to posture-based issues and work-related
factors (Necio et al. 2019; Shults et al 2020). Long hours of computer use
give a higher risk of the upper extremity symptoms of work-related muscu-
loskeletal disorders, evident with its high incident rates (Loh et al. 2018).
Due to the prolonged computer use and working without breaks, young
office workers have a relatively high prevalence of work-related wrist and
hand issues, including clinically proven CTS (Feng et al. 2021). In addition,
repetitive movements in keyboard typing harm people’s wrist and hands due
to the excessive pressure on the nerves (Wheeler, 2019). Thus, (De Putter
et al. 2012) mentioned that hand and wrist related injuries are one of the
most expensive injuries, constituting an average of US$740 million annu-
ally. Likewise, economic, and social pressures brought by musculoskeletal
© 2022. Published by AHFE Open Access. All rights reserved. 531

532 Lugay et al.
disorders among working-age population are immense that employers spend
at least US$103,000 for every 100 employees annually. In the United States
alone, 29% of the recorded injuries resulting from days of work attributed
to work-related musculoskeletal disorders (Daneshmandi et al. 2017).
Keyboard design has shown to influence wrist and hand postures that
affects median nerve deformation (Yeap et al. 2017). The abnormal flexion-
extension posture of the wrist joint, repetitive movements throughout the
day, and use of vibratory items were tagged as potential causes for the deve-
lopment of CTS (Bibi & Khan, 2019). Also, keyboard key spacing suggests
comfortability and productivity based on the International Organization for
Standardization (ISO). According to (Pereira et al. 2013), the optimal keybo-
ard key spacing length lies between 17mm to 19mm, and touch typing may
be a challenge for keyboard with key sizes less than 16 mm (Kim et al. 2014).
This paper investigates the effects of different keyboards on users’ pro-
ductivity and hand muscle strain. Specifically, this study identifies which
keyboard produces most words with fewer typographical errors in each time
frame and which keyboard has the slightest wrist and finger discomfort when
typing. The results of this study will benefit the working people considering
that office workers that use computers constitute a good percentage of Phi-
lippine labor (Philippine Statistics Authority, 2020). Moreover, the findings
are expected to improve the keyboard design, which will enhance the task
efficiencies of people and prevent the possibility of injuries.
METHODS
The researchers have collected the necessary data through actual data gath-
ering from invited participants; however, due to the COVID-19 restrictions
imposed in Metropolitan Manila, Philippines, only sixty-four participants
have voluntarily participated in this study. The participants were provided
with keyboards and asked to navigate the website application in the test con-
ducted. The application includes a five-minute fixed timer and immediately
starts when a person presses any key. With the test provided by the resea-
rchers, the test subjects were asked to type a random text as fast as possible
without stopping for the allotted five minutes. After the typing test, the par-
ticipants are required to answer a pain level questionnaire using a Likert
scale from 1 (no pain) to 5 (worst possible pain). Moreover, typing speed
and accuracy results were automatically shown on the application. Most
employers solely recognize certification results from a 5-minute typing test
(Meshulam, 2019).
During the data gathering, the participants were provided time to practice
the touch-typing method, as all participants do not have a background of
typing-related jobs or experiencing musculoskeletal disorders symptoms on
their hands, wrists and shoulders (see Figure 1). The manual typing test was
performed using a computer and a stopwatch; thus, a typing test application
was utilized in the study. Furthermore, this paper used the pain scale to deter-
mine the pain level experienced by participants. It is a tool that physicians use
to determine a patient’s level of discomfort as it can be used during a hospital
stay, a doctor’s visit, physical activity, or post-surgery (Weatherspoon, 2018).

An Analysis on the Effects of Different Types of Keyboards 533
Figure 1: Picture of one participant doing the 5-minute typing test.
Table 1. Variables used in the study.
Types of tests Independent
Variable
Dependent
Variables
Measurement
Unit
Measurement
Instrument
Pain Level Type of
Keyboard
Wrist/hand
pain level
5-Point Likert
Scale
Typing test
application
Typing Speed Type of
Keyboard
Typing Speed Words Per
Minute (WPM)
Typing test
application
Accuracy Type of
Keyboard
Typing
Accuracy
Percentage of
Accuracy (%)
Typing test
application
The independent variable used is thept different keyboards commonly used
in the Philippines. The dependent variables are pain level (ordinal), typing
speed (continuous), and accuracy (continuous) (see Table 1). The researchers
used a comparative research design to observe the impact caused by the inde-
pendent variable on the dependent variables. Since the factors involved were
continuous and ordinal, the Kruskal-Wallis H test was used. Kruskal-Wallis
H test (also known as the one-way ANOVA on ranks) is a nonparametric
rank-based test used to discover statistically significant differences among
groups of independent variables comprised of continuous and ordinal depen-
dent variables [Lund, 2020]. As the test was done using one-way ANOVA,
the parametric analyses for 2 to 9 groups were done by each group contai-
ning more than 15 [Minitab, 2019]. In the experiment, four groups had four
types of keyboards, each composed of 16 participants. Before starting the
data gathering, all Kruskal-Wallis H test assumptions were met and further
interpreted and analyzed using the SPSS 23 statistical software.

534 Lugay et al.
Table 2. Descriptive statistics of the study (N =64).
Variable N Minimum Maximum Mean Standard Deviation
Pain Level 64 1 5 2.83 1.432
Typing Speed 64 28.00 75.00 44.9688 11.66458
Typing Accuracy 64 91.00 99.00 96.0938 1.87480
Figure 2: Histogram of pain level test.
RESULTS
The descriptive statistics shown in Table 2 show that the overall pain level
mean is 2.83 with a standard deviation of 1.432. The overall typing speed
mean is 44.9688, with a standard deviation of 11.66458. Lastly, the overall
typing accuracy mean is 96.0938, with a standard deviation of 1.87480. The
64 respondents are grouped based on the 4 keyboard types (1 =Standard
Keyboard, 2 =Laptop Keyboard, 3 =Mechanical Keyboard, 4 =Foldable
Keyboard).
Based on Figure 2, the histogram of the pain level test showed the shape of
distribution scores from all the keyboard types. Based on the normal curves
presented, the forms are not similar across all the groups. With this, the Kru-
skal Wallis H-test cannot compare the median of the keyboard types; thus,
the mean ranks will be compared.
Figure 3 presents the histogram of typing speed test and typing accuracy
test, and it showed the distribution scores shape from all the keyboard types
considered. The shapes are not similar for all the groups from the normal
curves. Therefore, the Kruskal Wallis H-test cannot compare the median
of the keyboard types, which is the same as above, the mean ranks will be
compared.
Table 3 summarizes the hypotheses tests performed by the researchers,
the test used its significance value, and the decision based on the results.
In determining for the hypotheses to be concluded, the significance values
(p-values) will be utilized (Kurata & Matias, 2018; Kurata et al., 2015).
Based on the results, the typing speed test (p-value =0.000), typing speed

An Analysis on the Effects of Different Types of Keyboards 535
Figure 3: Histogram of typing speeding test and typing accuracy test.
Table 3. Hypotheses test summary.
Null Hypothesis Test Significance
Value
Decision
The mean ranks of the
groups in the Pain level
Test are the same.
Independent
Samples Kruskal
Wallis-H test
0.000 Reject the null
hypothesis
The mean ranks of the Pain
Typing Speed Test groups
are the same.
Independent
Samples Kruskal
Wallis-H test
0.000 Reject the null
hypothesis
The mean ranks of the
groups in the Typing
Accuracy Test are the same.
Independent
Samples Kruskal
Wallis-H test
0.037 Reject the null
hypothesis
test (p-value =0.000), and the typing accuracy test (p-value =0.037) all
are less than the alpha level of 0.05. Thus, it is concluded that the mean
ranks of the groups across the pain level test, typing speed test, and typing
accuracy-test differ from one another.
The mean rank of the types of tests done to the keyboard types used is
summarized in Table 4. It is evident on the results that the lowest mean rank
in the pain level is the mechanical keyboard (mean rank =19.47), followed
by the standard keyboard (mean rank =25.19), foldable keyboard (mean
rank =41.91), and laptop keyboard (mean rank =43.44) as the highest. It
determines that the participants experience the slightest pain level in using
the mechanical keyboard.
Second, typing speed has been measured by the researchers. The mech-
anical keyboard garnered the highest mean rank with a value of 48.81,
followed by the laptop keyboard, standard keyboard, and foldable keybo-
ard with mean rank values of 31.63, 27.66, and 21.91, respectively. Hence,
it is found out that most Filipinos can type faster using mechanical keybo-
ards rather than other options available. Finally, the highest mean rank is

536 Lugay et al.
Table 4. Kruskal wallis H-test mean ranks for different
keyboard type groups from pain level test, typing
speed test, and typing accuracy test.
Type of Test Keyboard Type Mean Rank
Pain Level Standard Keyboard 25.19
Laptop Keyboard 43.44
Mechanical Keyboard 19.47
Foldable Keyboard 41.91
Typing Speed Standard Keyboard 27.66
Laptop Keyboard 31.63
Mechanical Keyboard 48.81
Foldable Keyboard 21.91
Typing Accuracy Standard Keyboard 36.47
Laptop Keyboard 31.81
Mechanical Keyboard 39.31
Foldable Keyboard 22.41
Figure 4: Proper hand and body posture while typing (Adapted from Muller, 2020).
the most optimal among the keyboards in determining the ideal typing accu-
racy. From the results, the mechanical keyboard garnered the highest mean
rank (value =39.31), followed by standard keyboard (value =36.47), laptop
keyboard (value =31.81), and foldable keyboard (value =22.41). Overall,
it has been found that the mechanical keyboard is the optimum keyboard
across the three criteria considered in the study.
CONCLUSION
This paper investigates the effects of different keyboards on users’ producti-
vity and hand muscle strain. Specifically, this study identifies which keyboard

An Analysis on the Effects of Different Types of Keyboards 537
produces most words with fewer typographical errors in each time frame and
which keyboard has the slightest wrist and finger discomfort when typing.
Based on the results, the mechanical keyboard type is the most preferable
among the four types of keyboards available and based on the criteria used
(pain level, typing speed, and typing accuracy). This type of keyboard may
pose an excellent substitute for the available ergonomic keyboards in the
market based on the criteria considered.
Along with considering the use of the mechanical keyboard, the researchers
also recommend that the hand and body postures be improved while users
are using a computer keyboard. [Muller, 2020] highlighted the measurements
that computer users must apply while working (see Figure 4). In addition,
users’ hand should move freely and be elevated above the wrist rest while
typing to enhance the wrist’s mobility. Frequent short breaks also help the
users relax their hands and reduce the risk of having wrist injuries [Health
and Safety Executive 2018]. Finally, it is advisable that one avoid resting their
wrists on the desk, as this puts strain on an individual’s tendons and reduces
blood flow.
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