A case study about laptop using and ergonomic implications in a Brazilian university

Transcription

1 A case study about laptop using and ergonomic implications in a Brazilian university FRANZ, Luis Antonio dos Santos UNIPAMPA / Federal University of Pampa Bagé, RS, Brazil luisfranz@unipampa.edu.br GUIMARÃES, Iochane Garcia UNIPAMPA / Federal University of Pampa Bagé, RS, Brazil iochane@hotmail.com AREZES, Pedro Miguel Ferreira Martins University of Minho Guimarães, Portugal parezes@dps.uminho.pt ABSTRACT The continuous use of computers seems to represent an important predictor of ergonomic problems, in particular in what regards to musculoskeletal disorders. Among the available equipment, laptop computers have been growing in popularity among users in the more recent years. The current massive use of this type of computers will imply a need to carry out research focused in the potential health effects arising from its use. Thus, this study aims to identify the utilization pattern of this kind of devices and the associated ergonomics demands. This work was carried out using a sample of computers users of a university on the south of Brazil. The obtained results shown that the most frequent complaints regarding discomfort were related to cervical, lumbar and lower back, shoulders and right arm. Among those who use laptops, 46% of them use it between 2 and 5 hours daily, and 6 have their laptops for less than 2 years. 74% of the interviewed students have laptop, while amongst technical workers and teachers that rate is even greater, reaching 8 and 95%, respectively. Only 9% of respondents exclusively use laptops, with 74% of them reporting the alternate use between laptops and desktop. Additionally, it was found that almost 5 of the sample has indicated that weight as the main factor to be used for the selection of the computers in future purchases. Keywords: laptop computer, ergonomic, university users INTRODUCTION The use of personal computers has increased significantly in recent years [8]. The reduction in the cost of these devices and the emergence of alternative technologies are two examples of factors that contribute to this increase. However, and despite the advantages of these devices, its continuous use may result in ergonomic problems for its users, such as the development of musculoskeletal disorders [1]. Among the possible configuration of personal computers available in the market, laptops (or other related types such as netbooks or tablets) have physical features that can lead to the adoption of inappropriate postures during its use. Considering this, several authors pointed out, for example, that the screen position below of the eyes level and the high position of the keyboard can be important discomfort causes [1,2,4]. Additionally, the periods during which people use these

2 products for business or pleasure is also increasingly, and consequently the potential to cause health problems became a key element to be studied with more attention and emphasis. Universities, for example, are environments where this type of computers is frequently used, hence with a high probability for the occurrence of related [5]. The Federal University of Pampa (UNIPAMPA), located in southern Brazil, is an example where the use of laptops seems to be recurrent and is growing, both among students, administrative staff and teachers. This institution, comprising 10 different campuses, currently includes more than 5000 students, 392 teachers and 454 administrative staff and it is still under implementation. Hence, this place becomes an environment favourable to the study of solutions and preventive actions/behaviours in order to mitigate the risks associated to the use of laptop computers. Among the effects resulting from the continuous use of laptops, it is likely that the most discussed and frequent one may be the musculoskeletal disorders occurrence. This effect is very relevant and should worry the community, as it may affects several social players, such as the private companies, public companies and also affecting people at an individual level. Accordingly, one of the most noted loss is the absenteeism from the work activities due physical limitations imposed, for example, by Repetitive Strain Injuries (RSI) [3]. Thus, a work seeking to identify the causal factors of this kind of disorder may contribute to more adequate and effective preventive actions. It is also possible to infer that the general evolution of the characteristics of the furniture existing in educational environments was established in periods where personal computers were not an issue [6]. In recent years the available resources have different characteristics, which may cause physical additional demands comparing with those in the past. Thus, it is the authors believe that the study of these demands will help to identify some opportunities to adopt alternative and innovative improvements. Moreover, understanding the implications of the conditions and postures during the use of laptops may provide a theoretical basis for establishing an association with the teachers and students performance at the universities environments. This information may also support the proposition of solutions that will lead, ultimately, to the improvement of the academic activities. Considering the previous, this study aims to identify the utilization pattern of laptop computers and the associated ergonomics demands. METODOLOGICAL PROCEDURES This study reproduces, at least partially, a similar survey carried out at a Portuguese University, University of Minho, which occurred during the period comprised between May and July 2009 [2]. Therefore, some adjustments concerning the format of the data collection instrument and the way it was applied were adopted, aiming to adequate the survey to the local characteristics of the considered Brazilian sample. However, some care was taken in order to avoid that these differences can interfere on results. Study design This study was conducted at the Federal University of Pampa (UNIPAMPA), located in the Brazilian city of Bagé, near the south border with Uruguay. Data was collected from the application of a printed form, which was previously tested with a group of 30 individuals coming from different groups and activities within the University. Through this pilot-test it was verified the level of understanding and interpretation of the questions by the considered interviewees. At this pilot test, it was also estimated the mean answer time for each questionnaire, being approximately 5 minutes for each respondent. The survey was carried from September to December Each participant answered individually the printed form of the questionnaire.

3 Participants The sample used in this study consisted of 300 people, including students, teachers and other employees of UNIPAMPA, which represents approximately of the entire population working/studying at this institution. The questionnaire was conducted after the consent of the university administration. Questionnaire The survey consisted in collecting data through the distribution of a printed questionnaire containing a total of 15 questions, divided into two sections. If the interviewee did not have laptop, he/she would only answer the first eight questions. Otherwise, he/she should answer all the 15 questions of the questionnaire. The first seven questions were related with personal information, such as age, gender, current activity, course or section of the university of the respondent, hand dominance, computer type used at home or at the university and, finally, if he/she owned a laptop. The eighth question presented a human model similar to that one proposed by the Nordic Questionnaire [7] with some separation between specific areas, where the respondents could assign values indicating the frequency of occurrence of pain, and considering that these effects may be related to the use of laptop or desktop. The pain frequency was indicated through a scale with four alternatives in a crescent order of discomfort, including the following descriptors: never, rarely, often and very often. From the ninth question onwards, the questionnaire was answered only by those individuals who referred to own a laptop. In this section of the questionnaire, some aspects were introduced, such as the information of how long the respondent owns laptop, the screen size of the laptop and the average daily use. In turn, the issues related to laptop use postures and how the device is transported manually were also addressed. For easiness purposes, the questionnaire included in this point some scales based on pictures in order to facilitate the interpretation of the questions. The other questions were regarding the use of accessories or external devices connected to the equipment and features that could influence the when changing current computer with a new one. Finally, there was a space where the respondent could to introduce your address for to receive information with the obtained results in this research. Statistical analysis The collected data were entered into MS Office Excel 2007, where was realized the summarize statistics of the obtained information and also the comparison test between sample variables. The comparison between data groups were performed using Person Correlation Coefficient, with 95% confidence interval. RESULTS The obtained data show that the average age of respondents was 26.7 ± 8.4 years. The frequency distribution of ages is shown in Figure 1. Absolute frequency for age group % 3 25% 15% 1 5% relative frequency for age group [15, 20[ [20, 25[ [25, 30[ [30, 35[ [35, 40[ [40, 45[ Age group classes Figure 1 - Frequency distribution according of age group [45, 50[ [50, 55[ [55, 60[ [60, 65[

4 According the Figure 2, the sample reveals 159 (53%) male respondents and 141 (47%) of female. Regarding the actual activity, it observes 194 undergraduate, 19 teachers and 87 technical workers, all respondents whom entered in one of three categories. Gender Male Female 53% 47% Dominant hand Left hand 1 9 High hand Atual activity Computer undergraduate teacher technical staff other 65% 6% 29% Desktop Desktop+laptop Laptop None 22% 61% 16% Figure 2 General characteristics of studied sample 1% It s also observed that only 1% of respondents do not own a computer. Among the remaining respondents, 61% own or use both laptop and desktop. Still, 16% of other respondents have only laptop, while those with desktop computer (desktop) at home or university consisting of 22% of the sample. Referring to the dominant hand, 270 (9) of participants were right-handed and 30 (1) are left-handed. It was found that 61% of respondents using the laptop computer less than two years, and approximately half of these (3) have their equipment less than one year. Only 8% of the sample reported using the laptop more than 5 years. Was noted that regardless of the time they have laptops, users mostly use this equipment in 2 and 5 hours. An interesting fact is that the average period of use of the laptop increases proportionally to the time users have this equipment. Figure 3 summarizes this information. % time of average daily use 35% 3 25% 15% 1 5% 3 31% 31% 8% 0 a 1 year 1 a 2 years 2 a 5 years > 5 years > 8h 5h a 8h 2h a 5h 0 a 2h Time that own the laptop Figure 3 Average period using according the time that owns laptop It was identified that the majority of respondents (69%) uses laptop with the screen between 12 and 15 inches. Among these, one realizes that the time it own a computer does not interfere directly in the screen size used, as is presented in Figure 4.

5 % according the screen size 35% 3 25% 15% 1 5% 3 31% 3 8% 0 a 1 year 1 a 2 years 2 a 5 years > 5 years more than 15 between 12 and 15 less than 12 Time that own the laptop Figure 4 Laptop screen size associated with time that user owns computer With regard to posture and how to use the laptops, the highest frequency observed is the use of these on the table (58%). The current activity of respondents do not presents correlation with position of use of laptops. Then there is the lying position with the laptop on thighs () and then the position has been sitting with laptop on lap (17%). A lower frequency is observed for the position seat with the laptop on the surface where the person is sitting (on floor) (4%), according to Figure 5. % according to form that uses laptop % 17% on the floor lying sit laptop on thighs Activity 58% on table Figure 5 Postures most frequently during the use of laptop other technical staff undergraduate teacher Regarding the form that users normally carry the laptop manually, it was observed that most of them (57%) used a backpack, while use a handbag (valise), 13% use the bag with the strap draped over the same shoulder that supports the weight of the laptop and 8% use the bag strap across the torso. Only 1% of respondents use other ways to carry your laptop (see the Figure 6). In this case, the screen size does not seem to be correlated to the way the user carry your laptop.

6 % according the screen size Valise 8% bag strap across the torso 13% strap of bag on shoulder As carrying the laptop 56% Backpack Figure 6 How the users carry your laptops manually more than 15 between 12 and 15 less than 12 Concerning the use of peripheral devices connected to the laptop, it was identified that 51% of respondents do not use any device, 44% use the mouse connected to your computer, 4% utilize external keyboards and only 1% use base support. The use of other peripheral devices was not reported significant results on studied sample. Another important factor to be discussed is the characteristic most relevant to the user when to replace your current laptop for a new one, without considering the costs involved. In this sense, the weight given more frequently with 49%, which may show a low level of satisfaction and discomfort caused by the weight of this equipment. Following, there is the screen size with 18% of responses, the number of input/output connectors (11%) and finally, 6% for reflection screen laptop. Other possible reasons that would lead to exchange the computer totalled 16% how, for example, processing capacity and appearance. The frequencies of respondents considering the discomfort of the different areas of the body associated with the use of laptop and desktop are represented in Figure 7. Left side os respondent Never Seldon Often Very often Right side of respondent Never Seldon Often Very often Figure 7 Percentage distribution of the responses associated of the discomfort caused by laptop and desktop using It was observed that the areas with the highest frequency of discomfort due to computer use are in the region of the cervical spine, lower back, forearms, wrists and hands. In addition, more than 5 of participants reported discomfort frequent

7 in fourteen areas of the body related to computer use. Also it was found that seven regions of the body for more than 5 of some kind of discomfort (at least rarely), as shown in Figure 7. Statistical Analysis There is some correlation between age and activity, which seems to be an important finding, since it is natural that students tend to have lower age and technicians and teachers tend to have higher age. There is some correlation between complaints of discomfort in the upper limbs on both, left and right side. For example, for left and right shoulder has r=0.623, for left and right elbow has r=0.573 and for left and right hand has r= These results indicate that there is symmetry in relation to the sagittal plane in respect to pain, that is, the conditions are not likely to discomfort caused by asymmetrical factors, such as the use of the mouse. Is more likely what looks like monitor height, keyboard position, user's position are connected with complaints of pain. Has also identified a correlation between left wrist and left forearm (r=0.567), right elbow and right forearm (r=0.612), right wrist and right forearm (r=0.617). That is, the pains resulting from computer use are not specific and, apparently, involve multiple muscle groups simultaneously. DISCUSSION Based on the results of the collected data it can be identified that the majority of respondents had some type of computer, desktop or laptop. Therefore, this study corroborates the findings of Castellucci, Costa and Arezes [2], which has identified the growing use of laptops in universities. Regard the frequency of use of the laptop, it can be verified that the usage time increases associated with the time of acquisition of the laptop. It also identifies that the most frequently used means of laptop transport is the backpack, regardless of screen size. Regarding the reason for a possible change in the current notebook with a new one, most relevant feature identified was the weight, which can be directly associated with the screen size. Most respondents have laptop computers with screen sizes between 12 and 15 inches, which make their computers largest and heaviest. As for the discomfort experienced by laptop users, it was noted that the areas of highest incidence of pain is the region of the cervical spine, middle lumbar and lower back. One of the causes of these discomforts should be possibly used position for use of the laptop, since the sitting position with the laptop on the table represents the most used by respondents. Another fact responsible for this is the time of use of the laptop, where the majority of the users (92%) usually spend 2 hours or more per day using the notebook. CONCLUSIONS This study identified the characteristics and ways of use of laptops and discomfort due to these forms of use in a public university in the southern of Rio Grande do Sul, Brazil. According to the data analysis it was verified the existence of ergonomic implications in the region of the cervical spine, lower back, middle back, wrists and hands. The majority of respondents reported the occurrence of some kind of discomfort in areas that include trunk and upper limbs. The results of this study revealed the existence of any association between postures applies for using the computer and discomfort reported by users. In addition, this study will serve as the basis to possible improvement projects in the workplace or to help the university population, not only in the university under study, but other institutions with site conditions similar to those studied.

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