Abstract
BACKGROUND:
Students use a school bag to carry their school supplies which may not have the required standards and ergonomic factors.
OBJECTIVE:
This study was aimed to examine the ergonomic factors of schoolbags and their adaptation to the weight of elementary school students.
METHODS:
This cross-sectional study was carried out on 721 primary schoolchildren. To collecting data a checklist, which its final version was approved by the experts, was designed by researchers. Data were analyzed by using SPSS ver. 22 and Chi-square test, One-Way ANOVA, and univariate and multivariate logistic regression models.
RESULTS:
In this study, about 90.1% of students used a backpack to carry their items and most students carried backpacks with a weight up to 10% of their body weight. In 43.5% of the students, waist width was appropriate with backpack width at the bottom, and in 96.6% shoulder width was appropriate with backpack width at the top. Multivariate logistic regression showed that girls in compared to boys were more likely tolerated ratio of backpack weight to body weight, and also had more likely proportion of waist width and the backpack width at the bottom. The grades of the first, second, and fourth used more heavy backpacks. Students who their mothers were employee compared to housewives, carried heavier backpacks and had more likely proportion of waist width and the backpack width at the bottom. As the mother’s age increased, the proportion of waist width and the backpack width at the bottom is diminished.
CONCLUSION:
The schoolbags weight of many students was more than the standard weight, and their schoolbags did not have the required standards. Educational interventions can increase the knowledge of students and parents about the ideal weight of a schoolbag and the criteria for choosing a proper school bag.
Introduction
Students use different school bags to carry their belongings [1]. One of the best types of school bags to be carried by students is the use of a backpack, because of the appropriate distribution of weight between different organs of the body and lesser pressure [2]. It is necessary to be careful in choosing the type of backpack because the wrong type of backpack contributes to back pain and shoulder pain in students, while backpacks with two shoulder straps have more ergonomic design and exert less pressure to the body [3]. Using the backpack with two shoulder straps even if it weighs less than 10% body weight, will have a negative impact on the spine and cause pain [4]. An ergonomic and standard backpack should have lightweight, adjustable shoulder straps, wide and well-padded waist straps, and included many compartments to put on various items. The top of the backpack should not be higher than the shoulders and its bottom should not be lower than the upper part of the hip bone [1, 5–7].
Schoolbags weight up to 10% of the body weight increase energy consumption, bending head and trunk forward, thereby reducing the volume of lungs and increasing cardiovascular parameters such as heart rate, systolic and diastolic blood pressure [8, 9]. Carrying heavy backpacks improperly can increase the pressure on the joints and ligaments of the students and ultimately cause awkward posture, and pain in spinal, ankles, back, neck, and shoulder [1, 10–12]. Its unfavorable effects can affect the musculoskeletal system of primary school students, and its continuity will even affect the health of persons body structure in adulthood [13].
While most experts recommend that the maximum allowable portable load by students should not up to 10% of their body weight [2, 14]. The results of Paula study indicated that about 60% of students carrying schoolbags with the weighting of up to 10% of their body weight and about 25% of them complained of waist and shoulder pains [15]. As well the study results by Dockrell et al. showed that 70% of primary school children carried schoolbags up to 10% of their body weight [11]. The study of Roodbandi et al. revealed that 50% of primary school students used heavy backpacks and the prevalence of musculoskeletal problems was higher in them [16].
According to the results of previous studies in Iran, most of the students use a backpack to carry their school supplies; while in most of the backpacks, ergonomic factors have not been applied and do not have the required standards [7, 18]. Unfortunately, due to the lack of comprehensive anthropometric information in various Iranian populations especially students, the proper design of school bags is problematic. Most school bags are usually produced by copying foreign products, and importers are also due to lack of knowledge or unknown reasons distributed poor-quality products. It should be noted that students are forced to carry their school supplies between school and home on a daily because the closets are not provided in schools in Iran. At the same time, students carry food dishes and snacks in addition to their educational tools. Accordingly, with regard to carrying schoolbags from the early year of school and the extensive use of backpacks by students, this study aimed to investigate the ergonomic factors of schoolbags and their adaptation to the weight of elementary school students.
Materials and methods
Study participants and setting
This cross-sectional study was carried out on elementary school students in the Gonabad, a city in the southeastern province of Khorasan Razavi, Iran in 2017. At first, all primary schools of the city were identified and then two private schools and four public schools were randomly selected. Subsequently, all students of the 6 schools (n = 271) entered the study.
Criteria for entering the study include family and student consent for participation in the study, the absence of orthopedic or muscle and joint diseases, no history of fracture or dislocation in the past year, and ability to carry backpack by one shoulder and both shoulders. Exclusion criteria were any orthopedic and muscular disease and spinal or foot deformities.
A week before the started the study, the goals of the research were explained to students and then parents, and the informed consent form was obtained from them and they were assured that their information will remain confidential.
Measures
According to current extant research, in order to record the students’ profiles and collecting data a checklist was designed by researchers and contains three parts: The first part was related to demographic information of the students included gender, residency location, parent’s education level, parent’s job, type of school, school grade, and status location. The second part involved checking the characteristics of schoolbags used by students. Also, the third part was the record of student’s anthropometric measurements including shoulder width, scapula width, waist width, backpack height, the width of scapula strap, backpack width in the top and backpack width at the bottom. The final version of the checklist was approved by the experts who had plentiful experience on epidemiological researches.
Students’ weight was measured by a digital scale (SECA 803) with±0.1 Kg accuracy (students were weighed without shoes, veils, jackets, coats, etc.). The weights of the schoolbag and all its contents were separately measured by the MAHAK digital scale (MAHAK SCALE MDS 15000 B) with±0.1 Kg accuracy. To measure the height, the shoulder width at top and bottom of the students, and width of the backpack at the top and bottom was used a tape meter. Moreover, the equipment carried by students investigated and recorded in terms of standards. For example, backpacks were examined in terms of whether they had two straps, pad in the shoulder strap, lumbar strap, back lower layer, pockets, and necessary spaces. For measuring the reliability of the scales, the measurements were repeated in three different times, and again. Measurements were down during one month, in the morning shift and at the beginning of classes and before the consumption of snacks by students. It should be noted that the measurements were carried out at five stations and by ten professional health experts. Due to carrying different tools and books during the week and reducing measurement errors, these measurements were conducted in two different days of the week without previously notifying students.
Data analysis
Quantitative variables were stated as Mean±SD and compared by One-Way ANOVA; while Qualitative variables were expressed as frequency (percentages) and compared via Chi-square test. Univariate logistic regression analysis was conducted to assign the ratio of backpack weight to student weight and fitness the width of the back waist with backpack width based on the demographic factors. Significant variables were sieved for Multiple logistic regression analysis to subsequent explores this connection, which provided the odds ratio (OR). Data analysis was performed using SPSS V.22 and the level of statistical significance was considered as p < 0.05.
Results
The mean of age, weight, and height of the students were 9.82±1.81 years, 32.59±10.11 kg and 136.31±12.16 cm, respectively. 404 students (56.2%) of the samples were girls and 315 students (43.8%) were boys. Frequency distribution of backpack weight to student weight based on demographic factors is shown in Table 1. In this study, about 90.1% of students used a backpack to carry their items. Most students carried backpacks with a weight up to 10% of their body weight, and about 70% of the students in the first, second, and fourth grades carried backpacks up to 10% of their body weight. Girls usually carried significantly heavier schoolbags than boys (P < 0.001). Also, students of non-governmental schools carried heavier schoolbags than those of governmental schools, which was not statistically significant.
Frequency distribution of backpack weight to student weight based on demographic factors
Frequency distribution of backpack weight to student weight based on demographic factors
*Chi-square.
Mean of backpacks weight and its contents by educational grade is presented in Table 2. The mean of empty backpack weight was 0.584±0.217 kg and total backpack weight with all items was 3.38±0.960 kg. According to the results, there was a statistically significant relationship between the total weight of the backpack and the school grade (P < 0.001).
The mean of backpacks weight and its contents base on the school grade
*One-Way ANOVA.
The results in Table 3 illustrates the characteristics distribution of school bags types used by students. About 78.4% of the backpacks had a pad on the shoulder strap, 38.6% handbags had a shoulder strap, and 62.5% of the wheeled bags had suitable and sturdy wheels.
Distribution of the characteristics of school bags types used by students
The mean shoulder width and waist width of students were 32.51±3.42 cm, and 28.4±3.71 cm respectively. The mean of the dimensions of backpack width at the top and backpack width at the bottom was 23.29±3.01 cm, 29.19±1.89 cm respectively. In terms of proportion between of backpack size and student size, in 43.5% of the students, waist width was appropriate with backpack width at the bottom, and in 96.6% shoulder width was appropriate with backpack width at the top. Distribution of anthropometric dimensions of students based on demographic factors is shown in Table 4. The results of the chi-square test showed a significant relationship between gender, parent’s education level, parent’s occupation with anthropometric dimensions of students. (P < 0.05) (Table 4).
Distribution of the anthropometric dimensions of studied students
*Chi-square.
Table 5 demonstrates associations between the ratio of backpack weight to student weight based on the demographic factors using Logistic regression analysis. Multivariate logistic regression showed that girls compared to boys were more likely tolerated ratio of backpack weight to body weight (OR = 1.806). Students who their mothers were employee compared to housewives (OR = 1.724), carried heavier backpacks. Educational grades of the first, second, and fourth used more heavy backpacks (OR = 3.009; OR = 2.420; and OR = 2.575, respectively).
Logistic regression analysis in relation to the ratio of backpack weight to student weight
Logistic regression analysis about the fitness of the back-waist width with backpack width in the bottom is explained in Table 6. Multivariate logistic regression exhibited that girls compared to boys had more likely proportion of waist width and the backpack width at bottom (OR = 2.300). As the student’s age increases, the proportion of waist width and the backpack width at the bottom is slightly reduced (OR = 0.602). Students who their mothers were employee compared to housewives (OR = 2.317), had more likely proportion of waist width and the backpack width at the bottom. As the mother’s age increased, the proportion of waist width and the backpack width at the bottom is diminished (OR = 0.951). Likewise, the results of the logistic regression analysis showed that there was no significant correlation between the shoulder width and the width of the backpack based on demographic factors (P > 0.05).
Logistic regression analysis in relation to the fitness of the back-waist width with backpack width in bottom
This study was conducted among elementary students in a city in the eastern part of Iran. The aim was studying ergonomic factors of school bags and their adaptation to the weight of students. The results showed that most of the students used a backpack to carry their belongings. in previous studies, backpacks due to the symmetric distribution of weight were addressed as a more appropriate tool to be carried for school appliances [19–22].
In this study, the backpacks of most students did not have the required standards and there was no fit between waist width and backpack width at the bottom. Mohammadi et al. indicated that the backpack size of most students was not proportionate with their body dimensions and backpacks did not have the appropriate ergonomics [18]. Similarly, the results of the Mwaka et al. and Rashidi et al. studies suggested that students’ backpacks did not have appropriate ergonomics [21, 23]. At best, the backpack width should not be greater than the shoulder width. In other words, the backpack should be positioned almost in the middle of the back, parallel to shoulders and placed at a distance of a few centimeters above the waist; this is the best way to carry a backpack [8]. The reasons of the high level of usage of inappropriate backpacks by students can be due to lack knowledge of many parents about backpack standards and lack of attention to the necessary criteria and ergonomic factors causing them to purchase non-standard backpacks. On the other hand, for most students, the appearance of the schoolbag is the only thing that matters, and parents also give up against the insistence of their children. As a result, the lack of attention to the bag standard and only caring for its appearance can affect the student’s health. A study found that parents did not have the necessary knowledge about the standards school backpacks should have [24, 25].
Based on the results, the weight of the most students’ backpack was up to 10% of their body weight and there was no proportion between the weight of the backpack and the weight of the students. This value has been very different in various studies ranging from 40% to 71% [8, 26–29]. Usually, when a backpack is heavy, the neck and trunk move in forwarding position placing abnormal forces on the body. Also, the back of the child may be pulled back too far and increase their potential lordosis, which can lead to changes in the body shape to the front or one side [9, 15]. Creating shelves in schools for putting student’s materials, offering a regular student schedule by the teacher, holding classes for students, and checking the weight of schoolchildren’s bags by their parents can help reduce the weight of schoolbags.
Here, the gender, mother’s occupation, and education grade were among factors affecting the proportion of the backpack weight to the student’s body weight. The girls used an unfit and heavier backpack in comparison than boys. The heavier weights of girls’ backpack compared to that of boys can be attributed to the fact that elementary girls carry more things, thus parents of girls choose backpacks larger than their body when shopping and do not pay attention to its proportion with their body size. Girls in elementary school seem to like to carry more personal belongings because of more sensitive and therefore they have heavier backpacks compared to boys. Similarly, In Kellis’s study, girls carried heavier backpacks than boys [30]. Also, Dianat’s study concluded that the cause of carrying heavier schoolbags by girls was suggested as a behavioral issue for children, i.e. girls tend to take more educational materials if suggested by the teacher [20]. The results of the meta-analysis study showed that girls reported excessive back pain due to carrying heavy backpacks and, with age, they experience more back pain [31].
In this study, the backpack weight of the first, second, and fourth-grade students was up to 10% of their body weight. The study results of Mansoor Bostani et al. in Iran showed that there is a significant relationship between grade and backpack weight, and students in the first, second and fourth grades carry a heavier backpack [32]. The results of Batista study on elementary school students showed that the backpack weight of the second, third and fifth-grade students was higher than other bases [33]. Whittfield’s study on New Zealand showed that students backpack weight of the third and sixth grades were heavier than other grades [34]. Also, results of the Al-Saleem’s study in elementary students showed that students in 4 and 5 grades were carried a heavier backpack than other grades [35].
The results revealed that students whose mothers and fathers were employed, more likely to use backpacks with a weight of up to 10% of their body weight. Parents who are employed do not usually control their children schoolbags regarding weight and its content, due to their occupation and lacking enough time in the morning compared to housewives. Also, mothers who are housewives usually prepare their school bag for their children and refuse to put out unnecessary equipment and check the weight of the school bag. A study by Barkhordari et al. found that only 23% of parents check their children’s’ backpacks, and students whose parents do not check their backpacks carry more books and educational materials to school and thus carry heavier backpacks [26]. Also, the study results of the Forjuoh et al. showed that 96 percent of parents never checked the weight and contents of their children backpack [36].
In the present study, no statistically significant relationship was observed between the proportion of backpack weight to student weight based on the type of school, though non-profit school students used more backpacks with a weight of up to 10% of their body weight. Spiteri et al. showed that students in non-governmental schools used heavier backpacks and lower back pain was also higher in these schools [29]. The study by Zakeri et al. demonstrated that most of the non-governmental school students had nonstandard weight backpacks [37]. Students in non-governmental schools, probably due to the economic situation and social status of their parents, as well as the extracurricular programs that these schools hold require more books and notebooks, making students of these schools use heavier backpacks. The use of heavy and inappropriate backpack can cause undesirable effects on the musculoskeletal system in adolescence. Students in nonprofit schools, probably due to the economic situation and the social status of their parents, as well as the extraordinary programs that these schools carry out requiring more books and offices, will make the students used of these heavy backpacks. The use of heavy and inappropriate collateral can cause undesirable effects on the musculoskeletal system in adulthood.
One of the strengths of this study was that the information was not self-reported by the students and all the information was completed by the researchers to reduce the error rate. To achieve this, training sessions were held for the researchers before collecting information and explanations were given on the questionnaire and how to collect the required information to avoid ambiguity. Nevertheless, this study had limitations including not checking the students’ body abnormalities, not surveying the knowledge and attitude of students, parents and teachers were not studied about of the criteria for choosing a good school bag.
Conclusion
Based on the results obtained in this study, waist width was not proportionate to the backpack width at the bottom in most students. However, in most students, shoulder width was in proportion with the backpack width at the top. Most backpacks used by students did not have the ergonomic factors, and most students did not use backpacks correctly. Accordingly, policymakers need to apply sufficient supervision on how to make backpacks, etc. and adopt policies for the production of ergonomic products. Parents also need to receive the necessary knowledge about the criteria for choosing the right backpack, and students should also obtain the necessary knowledge about the correct use of backpacks. Considering the large figure of students in Iran, observing ergonomics in choosing the type and weight of the schoolbag is of great importance and its training may be useful in maintaining the health of this massive population. Also, education should also pay more attention to this issue, and schools should also receive the necessary training in this area. Further, proper planning can prevent students from carrying unnecessary and heavy equipment. It is suggested that in future research programs, educational-interventional programs be held for students, parents, school administrators, and teachers.
Conflict of interest
None to report.
Footnotes
Appendix
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Acknowledgments
This study is based on the research project approved by Social Determinants of Health Research Center of Gonabad University of Medical Sciences with the code of ethics IR.GMU.REC.1394.101 (Proposal code: SDH/2/014). The authors would like to express their deepest appreciation to the students, teachers, school principals, and all staff of the Social Determinants of Health Research Center who assisted the authors to run this research project.