The Correlation between Position and Duration Use of Laptops with Musculoskeletal Disorders (MSDs)

TYPE OF ARTICLE: Research Abstract: The pandemic period forces all learning processes to be carried out online by utilizing internet facilities with a laptop. The position of using a laptop that is not ergonomic can cause musculoskeletal disorder. This study aims to determine the correlation between position and duration of student use of laptops during online learning with Musculoskeletal Disorders (MSDs). This research is analytic observational with a cross-sectional approach. The research was conducted on active students of the Medical Study Program, Muhammadiyah Palembang University, with 416 respondents. Primary data collection was taken using a questionnaire with a Nordic Body Map score. The analysis technique used the ChiSquare test. The results showed that the respondents had a high duration of laptop use (48.8%), with a not good position (42.3%).Most musculoskeletal disorders were felt in the neck (75.5%). There was a correlation between the position of using a laptop and musculoskeletal disorders (p 0.652). However, there was no correlation between the duration of laptop use and musculoskeletal disorders (p 0.002). It can be concluded that the position of using a laptop that is not ergonomic caused musculoskeletal disorders.


INTRODUCTION
The pandemic period forces all activities to be carried out remotely from home. Activities, including student learning, were carried out online by utilizing internet facilities. Students use laptops by utilizing internet facilities as a learning tool. 1 The use of laptops, which have only been used in tracing the learning literature, is now the primary medium for learning at home. The duration of using laptops increases during online learning.
Using a laptop that is not ergonomic can cause complaints to the back, shoulders, or other organs that lead to musculoskeletal disorders. According to Riskesdas, the prevalence of MSDs disease based on the diagnosis of health workers mainly was in Bali 19.3%, East Java 26.9%, while the highest one was NTT 33.1%. The prevalence of MSDs can occur with increasing age. At productive age, the risk of experiencing MSDs complaints is generally among students whose age range is 15-24, namely 1.5-7%. 2 Based on research conducted by Wicaksono et al.,91.7% of architectural engineering students have experienced MSDs due to the use of laptops. Meanwhile, the results of work posture of 78.3% made changes in posture while working. It revealed that 6.7% of students used laptops> 2 hours every day and 63.3% used laptops with a frequency of> 5 days. 3 The use of a laptop makes the space for the hands to type narrow, wrists that do not fit, the position of the elbows is not suitable, the wrong sitting position is bent, and the head is bent forward. When sitting using a laptop, the body position is an upright chest and not bending over; the laptop is placed on a table with an inappropriate table height and a chair without a backrest. 4 It can lead to health problems of MSDs. If the muscles continue to receive static loads repeatedly, there will be musculoskeletal complaints in muscles, joints, tendons, intervertebral discs, peripheral nerves, and the acute to the chronic vascular system. The frequent complaints include mild to severe pain, swelling, redness, tingling, heat, soreness, numbness, muscle and joint stiffness, weakness and loss of hand coordination. 5 According to some experts, several factors cause MSDs, namely occupational factors, work factors, environmental and psychosocial factors. Work factors include work posture, duration, workload, frequency, and coupling tools. Meanwhile, worker factors include age, gender, working time, years of service, exercise habits, and Body Mass Index. 6 Based on the research by Sari, age is associated with musculoskeletal disorders in laundry workers with a pvalue < 0.005. In addition, the work is done using high muscle strength and repetitive movements. It is similar to the research from Prawira revealing a relationship between age and musculoskeletal complaints in students in Bali. The complaints were primarily felt in the back and waist because they had to sit for 5-6 hours a day. 7,8 A study on students of the Department of Informatics found no significant relationship between the duration of using a laptop and the musculoskeletal complaints experienced. Thus, based on the results of previous studies, researchers are interested in conducting research to identify the correlation between the position and duration of using laptops with musculoskeletal disorders in medical students during online learning.

METHODS
This research is analytic observational with a cross-sectional approach. The study has received approval from the research ethics committee in Unit Bioetika dan Humaniora Kedokteran Islam (UBHKI) Faculty of Medicine Universitas Muhammadiyah Palembang. The research was conducted on students of the Medical Study Program, Faculty of Medicine, Muhammadiyah Palembang University, who met the inclusion and exclusion criteria with a total sample of 416 respondents in February-March 2021. The inclusion criteria were active students of the medical study program and willing to participate in research with informed consent. Meanwhile, exclusion criteria included having a history of and suffering from musculoskeletal diseases such as Rheumatoid arthritis, osteoarthritis, and spinal disorders (kyphosis, lordosis, scoliosis).
Primary data collection was carried out using a questionnaire. The process of distributing questionnaires was carried out by giving questionnaires to respondents online through a google form. The research variables in the form of the duration of using the laptop and the laptop's position were determined by using a questionnaire of using the laptop and its body position. Musculoskeletal complaints were measured using a Nordic Body Map questionnaire, including scoring of complaints in the neck, shoulders, elbows, upper and (NBM) lower backs and arms, thighs, knees, hands, and feet which were categorized into 4, namely; no pain got a score of 0, a mild pain got a score of 1, moderate pain get a score of 2, and severe pain get a score of 3. The level of MSDs complaints was considered non-existent if the total NBM score was less than 28 and mild if the total NBM score was 28-49. Moreover, it was moderate if the NBM score is 50-70 and severe if the NBM score is 71-111. 6. The collected data were processed in univariate form with the frequency distribution and bivariate analysis using the Chi-Square test with a significance level of 0.05.

RESULT
There were a total of 429 respondents who filled out the questionnaire and obtained 416 respondents who met the inclusion and exclusion criteria with the characteristics of the respondents as shown in Table 1.   Table 2 shows that most respondents, namely 203 people (48.8%), used laptops with high duration, and most respondents, namely 176 people (42.3%), used laptops in a not good position.   Table 4 shows the frequency distribution of respondents based on the severity of the musculoskeletal disorders felt in each body part due to using a laptop. The mildest complaints were felt in the neck (56.9%), while the most moderate and severe pain complaints were felt by respondents in the lower back, with a total of 25.7% and 3.9%, respectively.  Table 5 shows the frequency distribution of respondents based on the presence or absence of complaints based on the calculation of the total score. If the total score is <28, it is categorized as no complaints. Moreover, if it is > 28, which is included in moderate and severe complaints, it is included as the complaint category. Based on the results of the study, it was found that the majority of respondents of 254 people (61.1%) had musculoskeletal disorders. * Chi-square analysis Table 6 shows that the respondents with a high duration of laptop use had musculoskeletal disorders. Statistically, the results showed a p-value of 0.652 (p > 0.05), indicating that there was no significant relationship between the duration of laptop use and musculoskeletal disorders. In the case of respondents with a poor laptop usage position, the majority had musculoskeletal disorders, and statistically, the results showed a p-value of 0.002 (p < 0.05), indicating that there was a significant relationship between the position of laptop use and musculoskeletal disorders.

DISCUSSION
Many factors influence musculoskeletal complaints, including unnatural work attitude, long and static sitting, repetitive activities, and individual factors such as age, gender, body size, and body organization. Noor's research showed a correlation between age and years of service with musculoskeletal complaints in brick craftsmen. Putri also mentioned a relationship between age, work period, and work posture with complaints of musculoskeletal disorders. Furthermore, Fathoni et al. (2009) also stated there was a relationship between age and length of work with Low Back Pain for Nurses in Purbalingga District hospital. [9][10][11][12] Based on the research results, it was found that the duration of student use of laptops was high during the pandemic. In addition to making lecture assignments, laptops are a routine activity in supporting the learning process online. Moreover, the study also revealed that the musculoskeletal disorders experienced by students of the Faculty of Medicine, Muhammadiyah University of Palembang, were not related to the duration of using a laptop. The results of this study are in line with research conducted by Wijaya, Kurniasari, Lahdji, and Ali on students of the Department of Informatics, Yogyakarta State University, denoting that there was no significant relationship between the duration of using a laptop and the musculoskeletal complaints experienced. Besides, Lahdji's research also found no relationship between the length of work and Musculoskeletal Disorders in Laundry workers. Ali's research found that there was no significant relationship between the duration of using a laptop and the health complaints that were felt due to the use of a laptop. [13][14][15] In addition, Tjahayuningtyas's research (2019) showed work period has a relationship with the musculoskeletal disorder (p 0.019). 16 The maximum duration of each laptop use is two hours. In theory, a longer duration can lead to greater exertion, abnormal posture, and static posture. The duration of work for a person determines the level of work efficiency and productivity. 5,6 Based on the study results, the musculoskeletal disorders experienced by students of the Faculty of Medicine, Muhammadiyah University of Palembang were related to the position of using a laptop. The results of this study are in line with what was done by Ali to the employees of the Subang District Health Office. 14 It was found a significant relationship between body position when using a laptop and perceived health complaints. Furthermore, the results of this study are also in line with the results of research by Wicaksono et al. on students of the Faculty of Engineering, Department of Architecture, Diponegoro University, who found a relationship between work posture and musculoskeletal complaints with a p-value of 0.030. 3 Besides, complaints on the lower and upper back are common complaints. It can occur due to bad sitting posture, such as an unstable body position, forming an angle of 90-100 0 . In addition, it can also be caused by sitting without leaning on a chair, and the respondent rarely stretches the two parts of the body. 6 Many respondents also felt complaints about the neck. The position of the head when using the laptop is looking down or looking up, which also causes the muscles to become tense quickly. This bowing position can be caused by the low table position so that it is not under the anthropometry of the body. The position with the high table also causes the neck to be raised more so that it is not under the anthropometry of the body. 7 In addition, neck pain was also caused by the respondent not stretching his body every two hours for 15 minutes while using a laptop. These results are in line with Situmorang's research where there is a relationship between overall posture and use of the neck with complaints of Neck Pain in education personnel from the Faculty of Public Health, Diponegoro University. 5 Furthermore, there are also many complaints about the shoulder. It can happen as the respondent does not lean on the chair when using the laptop. The position of the table is too high so that the elbows do not form 900 and do not stretch the body, causing the shoulder muscles to become tense and sore. 18 The subsequent most common complaint is on the hips/thighs. It can occur since the position of the respondent's feet when using the laptop is not under ergonomic principles such as hanging one thigh to another, hanging legs (not tread on the floor), folding the legs, both on the floor and in the chair while sitting. These positions cause the unsmooth flow of blood to the lower body. Thus, to prevent a static body position, stretching the body is necessary. It functions to improve blood circulation in the body so that the oxygen supply throughout the body is fulfilled. 19,20 In Dinar's research, there was a significant relationship between the ergonomics of the chairs used when working and musculoskeletal complaints, namely the length of the chair and buttocks-popliteal (p 0.04). In line with the research, Jalajuwita and Indriyati's research in 2015 also found a significant relationship between the work position and musculoskeletal complaints in welding workers and showed a moderate level of correlation. Daika's research also concluded that the working postures have a mild correlation (r 0.407) with musculoskeletal disorder complaints. [21][22][23] Based on the explanation above, respondents who used laptops for more than six hours and in improper positions had the possibility of experiencing moderate to severe musculoskeletal complaints. In static muscle work, blood vessels are compressed by the increased pressure in the muscles due to contraction, causing blood circulation in the muscles to be disturbed. In dynamic muscle work, it increases 10-20 times of the static muscle work. Muscles need energy when they contract. The energy comes from the breakdown of ATP (Adenosine Triphosphate) molecules into ADP (Adenosine Diphosphate) in the muscles. If the contraction continues, energy is taken from glucose compounds due to the obstruction of blood circulation that channels oxygen, food materials, and metabolic waste. Glucose will undergo glycolysis into pyruvic acid and ATP, which will be used for muscle contraction. Pyruvic acid in muscle cells can be converted into lactic acid. Lactic acid built up in muscles can cause soreness, pain, or fatigue. 6,24 In terms of limitation of this study, there is no measurement of the ergonomics of the chairs used so that it cannot simultaneously assess the correlation of chair ergonomics and musculoskeletal disorders.

CONCLUSION
Based on the result of this study, it is concluded that there was no correlation between the duration of using laptops during online learning and musculoskeletal disorders. However, there was a correlation between the position of using laptops during online learning and musculoskeletal disorders.