Jurnal UMP Social Sciences and Technology Management
Vol. 3, Issue. 3,2015
Kyphosis and Its Relationship with the Weight of Backpack
and Bag of Female Students1
Karim Salehzadeh,
Assistant Professor, Department of Physical Education, Faculty of Educational Sciences,
Azarbaijan Shahid Madani University, Tabriz, Iran
Corresponding author: [email protected] `
Roghaiye Poursafar Bonab
M.A Student of Department of Physical Education, Malekan Branch, Islamic Azad University, Malekan, Iran
Abstract
Defining the factors affecting spinal disorders in female students and the direct effects of
carrying heavy loads, their weight and type during school years is the main reasons behind
conducting such studies. In order to do so, the paper attempts to investigate the relationship
between Kyphosis disorder and the weight of schoolbags and backpacks in female primary
and high school students. Statistical population of this study included all 10324 female
students aged between 7 and 17 in Bonab. Using Morgan table, 370 students were selected
through random cluster sampling and the rate of their Kyphosis was measured using the
checkerboard. SPSS 21 computer application was used to do statistical calculations and the
data were analyzed through independent T and Chi-square tests. The study revealed that
weight and type of a bag could affect creation and development of Kyphosis disorder.
Moreover, the rate of Kyphosis in primary school students was much higher in girls carrying
backpacks compared to the ones carrying handbags. Yet, the study failed to find a significant
relationship between Kyphosis disorder and weight and type of bags in high school students.
It seems as if, choosing proper type and weight for the backpack along with the time a female
primary school student carries it must be reconsidered, decent corrective exercises ought to
be prescribed and the proper basis for their physical activities has to be provided.
Keywords: Corrective exercises; Female students; Kyphosis; Backpack; Schoolbag
Introduction
The level of individuals' health in a society is an important index of development in countries. The future of
a country greatly depends on dynamism and health in both mental and physical way of the adolescents and
youth in that country so that healthy and strong individuals are the biggest national capital of a society
(Xiangrong et al., 2014).Among all social institutions, school is one of the best officially organized
institution which can flourish the kids and adolescent of a society by providing a healthy mental and
physical context (Sankarson et al., 2014). All along school years the kid experiences physical, intellectual,
emotional and social changes and if the environment is not ready for their perfection, various growth
disorders and diseases may emerge (Emerson et al., 2014). Various models of bags available in the market
encourage students to use different types without worrying about muscular and physical problems they
may cause. Backpacks, front packs, double packs, front backpacks, low back packs, shoulder bags, hand
bags and wheeled bags are only some of their types. Daily carrying of these bags impose heavy loads on
spinal cords of young students and is the main reason for their disorders (Charles et al., 2014 &
Daneshmandi et al., 2011).Several studies in different countries on bags, body posture change while carrying
them and neglecting ergonomic principles in their design and their effect on children’s health. Some of
these studies have concluded that improper carrying of bags, their heavy weight, bad form and size of them
and the duration of their carriage are important reasons for lower back pains (Haselgrove et al., 2008).
Backpacks are of special popularity among different groups of individual specially students of young ages
1
Acknowledgments
This paper is extracted for an MA thesis by Roghaye Poor-Safar supervised by Dr. Karim Salehzadeh in the Malekan Branch, Islamic Azad University, and
Malekan, Iran. Hereby, the authors would like to offer their heartiest gratitude form the head of the department of school education in Bonab and all
school principals and head masters and mistresses whose contribution made this research possible
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(Hussaini et al., 2012). Nonstandard body posture in students while carrying heavy bags to school have
raised concerns in parents, teachers and health authorities in the society and have made researchers
interested in adverse effects of bad bags ([Hussaini et al., 2009). Long-term effects of carrying bags on body
are not yet discovered; however, loads imposed by these bags may have essential roles in skeletal-muscular
disorders in students (Tarkeshwar et al., 2009). Two main disorders thought to be induced by carrying bad
backpacks are kyphosis and scoliosis (AL–Khabaz and Shimada, 2008 & Gray et al., 2007). Researchers have
found that carrying backpacks weighing over 10% of the body weight ends in kyphosis and lower pulmonary
capacity in individuals (Mihailova et al., 2014 & Dorostimotlag et al., 2009).Studies have revealed that heart
rate, blood pressure and energy used increased in 10 year old students carrying bags of weights over 10 and
20% of their body weight (Hong et al., 2008). Moreover, carrying backpacks weighing over 10% of body
weight induces kyphosis and lower pulmonary activities (Mohammadi et al., 2012). Researchers have
reported that weight and length of carrying backpack induces negative changes in students’ shoulders and
necks (Cleiton et al., 2014 & Mohan et al., 2007). Skeletal disorders related to carrying bags are concurrent
effects of factors like extra weight, size, form and length of carrying bags by students (Mihailova et al.,
2014). Furthermore, they believe that the main reason for physical problems of sitting and walking or even
awkward posture must be sought in bad habits of carrying heavy loads like bags full of books, bags hanging
from one side of the body or carried by one hand (Cleiton et al., 2014). Besides, loads carried by students
may risk their health and cause muscular pains, back pains, walking problems, deformed body parts and
backaches (Mackie and Legg, 2008). Nowadays, backaches are among the most common complaints adults
have all around the world and several reasons prove the relationship between backaches in kids and
adolescents and backaches in adults (Sankarson et al., 2014). In case, a solution is offered for this long
lasting costly problem of the kids and adults, it will become an everlasting attempt (Mohammadi et al.,
2012). Researchers suggest backpacks maximum weight to be 10 or in some cases 20% of the body weight
(Denise, 2008). However, the range proposed by majority of researchers is between 10 to 15% of the body
weight (Devroey, 2007; Chow et al., 2010; Hussaini et al., 2009). Desired weight of backpack for primary
school children must not exceed 7.5 to 8% of their body weight. Yet, there should be more investigations on
the relationship between damages induced by backpacks and factors like their design, and personal factors
like physical fitness along with compatibilities while carrying them. Anal investigated female students and
observed strong connections between school bags, their carriage and backaches. Besides, the ratio of
backpack weight and students’ body weight was significant. Nevertheless, Mostafazadeh did not report any
significant relationship between bag and backpack weight with scoliosis and kyphosis disorders in his
studies on primary school boys (Mostafazadeh, 2005). Most of the students in primary and high schools use
backpacks to carry their staff most of which are heavy. Carrying these bags along with their weight and size
and the students’ posture are drawing attention from parents, teachers and physicians (Daneshmandi et al.,
2011 & Hussaini et al., 2012).some studies have found that some 50% of students have bad habits of carrying
things and bags (Daneshmandi et al., 2010). In a study on Iranian boys carrying backpacks, it was discovered
that, younger students tend to imitate from their older counterparts and the weight of their bags are equal
or sometimes heavier than that of older students carried bags (Zamanian et al., 2014). Therefore,
considering the importance of investigations on the reasons behind disorders of back, backaches (Amal,
2012) and kyphosis in primary and high school girls while carrying bags and studying and the few studies
conducted on the relationship between length of carrying bags, their weight and their type with spinal
disorders in young female students, the present study will try to pioneer investigations on prevalence of
kyphosis and the relationship between backpacks and this disorder. It will also try to give suggestions on
correct methods of carrying bags and backpacks by young female students to avoid various disorders
including kyphosis in the society.
Methodology
This descriptive field study is a quasi –experimental one, the hypotheses of which were evaluated through
independent t and X2 tests. The statistical population of the study included all 10324 female students aged
between 7 and 17 years (5954 primary school and 4370 high school students) studying in Bonab in the
school year 2014-15. Statistical sample was selected through stratified cluster sampling put into different
classes via randomly. These students were divided based on their family income and region of residence to
far rural, near rural, suburb, downtown, well off families and low income families. Then with proper
assignment from each class, samples were selected. Sampling from each class was conducted randomly and
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according to the table of random sampling. Overall number of samples from each class had to be equal to
the number of overall sample needed. Considering the size of the statistical population and according to
Morgan table, statistical sample was decided to include 213 student of primary school and 157 students of
high school making an overall of 370 subjects. Morgan table calculates the size of the statistical sample
using the following equation:
S=
Where S is the size of the sample, N is the number of individuals in the society, d is the population ratio
taken as 0.5 and P is the X2 value with one degree of freedom in confidence level of 0.95. Since some of the
variables and collected data were of gradable nature, non-parametric X2 was used along with descriptive
statistical methods and independent t test and the data acquired were analyzed using SPSS 21 computer
application. In order to evaluate the condition of spinal cord, following devices were utilized. A
checkerboard along with a vertical line with confidence level of 95% and reliability was used to measure
kyphosis disorder in students (Rajabi, 2012). Digital scale with 0.1 kilogram precision capable of calibration
(ws80 model, made in Switzerland) was utilized to record weight of the subjects and a height meter with
minimum error of 0.1 cm with a broca plate (Machinen-AG, made in Switzerland) was used to measure their
heights. Investigations on spinal cord was conducted using a checkerboard with a vertical line and several
considerations were made not make any damage and observe cultural and ethical rules of each social class
the subjects had come from in the posterior and lateral:Investigating the spinal cord from the posterior: the
subjects stood beside a checkerboard wearing tight clothes and not wearing shoes and the vertical line
hanging evaluated and examined the condition of shoulders (asymmetry of shoulders), deviation of spines
(diagonal back), condition of the scapula (asymmetry of lower angels). In normal condition, vertical line
was parallel with occipital bone, the seventh cervical vertebrae, along with shock frills and between two
lobes of thigh. The vertical line on the lateral view had to be parallel with the middle of auricle, middle of
shoulder, the big frill on thigh bone, on the side of patella, and front of the ankle (Letafatkar and
Abdolvahabi, 2010). In the first stage, all the equipment needed were installed in the prayer hall and
healthcare office of the school and then subjects were informed about different stages of the study along
with physical disorders. Later on, their spinal cord condition was examined in front of the checker board
with tight clothes on and finally, weight, size, and type of backpacks were measured without prior notice
and the weight and height of the subjects were recorded as well.
Results
In order to evaluate the significance in the difference of backpack weight of primary school students in both
healthy subjects and the ones suffering kyphosis, independent t test was applied. Results for the t test for
both groups are represented in table 1.
Table 1. independent t test and descriptive statistics on backpacks’ weigh in primary schools in
healthy and kyphosis cases
Disorder
average
Standard
Levine test, Variance
t statistics
Level of
deviation
equality
significance
Disordered
2.671
0.56
F
Sig
5.61
0.000
Healthy
2.177
0.50
2.58
0.109
5.26
0.000
According to table 1, t test on comparing the backpack weight of primary school kids in both healthy and
kyphosis groups revealed that there is a significant difference in the weight of backpack for both groups
under study (P=0.000). Average weight of backpack for kids suffering kyphosis was 2.671 while average
weight of backpack for healthy students was 2.177. The difference between bags of these two groups was
0.494 gram and statistically speaking this difference is significant (table 1).
In order to evaluate the significance in the difference of backpack weight of high school students in both
healthy subjects and the ones suffering kyphosis, independent t test was applied. Results for the t test for
both groups are represented in table 2.
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Table 2. independent t test and descriptive statistics on backpacks’ weigh in high schools in
healthy and kyphosis cases
Disorder
average
Standard
Levine test, Variance
t statistics
Level of
deviation
equality
significance
Disordered
3.58
0.84
F
Sig
0.39
0.695
Healthy
3.52
0.79
0.52
0.46
0.38
0.70
Average weight of backpacks in subjects suffering kyphosis is 3.58 and for healthy students it is 3.525. The
difference in the weight of bags is 0.055 gram and the difference is not statistically significant. According to
table 2, t test for comparing backpack weight in high school students suffering kyphosis and the healthy
ones it can be concluded that the relationship between backpack weight in healthy and kyphosis high
school students is not significant (P=0.695). In order to test the significance of the relationship between
2
carrying backpack by primary school girls and the possibility of kyphosis disorder, X test was applied (table
3).
Table 3. investigating the cross relationship between carrying bags in primary school levels
with the possibility of kyphosis
2
Carrying
kyphosis
total
X
Degree
Two-tailed
backpac disordered healthy
value
of
level of
k
freedom significance
2
Hand
0
3
3
Pierson X
10.711
2
0.005
One5
61
66
Ratio of possibility
12.662
2
0.002
sided
Backpac
38
106
144
Line to line continuity
10.466
1
0.001
k
total
43
170
213
Number of credible
213
cases
Considering the results from cross table on carrying backpack by primary school girls and the possibility of
kyphosis, from among all 213 students under study, 170 subjects were healthy and 43 were suffering
kyphosis. Three students were carrying hand bags all of whom were healthy. 66 students used one-sided
backpacks 61 of whom were healthy and 5 were suffering kyphosis. 144 students were carrying backpacks
2
106 of whom were healthy and 38 were suffering kyphosis. According to the results from table 3, on X test
on the relationship between carrying backpacks by primary school students and the possibility of kyphosis
disorder, it can be concluded that there is a significant relationship between carrying backpacks and
possibility of kyphosis disorder in primary school girls (P=0.05). In order to test the significance of the
2
relationship between carrying backpack by high school girls and the possibility of kyphosis disorder, X test
was applied (table 4).
Table 4. investigating the cross relationship between carrying bags in high school levels with
the possibility of kyphosis
2
Carrying
kyphosis
total
X
Degree
Two-tailed
backpac disordered healthy
value
of
level of
k
freedom significance
2
Hand
15
29
44
Pierson X
3.051
2
0.217
One15
47
62
Ratio of possibility
3.090
2
0.213
sided
Backpac
20
31
51
Line to line continuity
0.371
1
0.542
k
total
50
107
157
Number of credible
157
cases
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Considering the results from cross table on carrying backpack by primary school girls and the possibility of
kyphosis, from among all 157 students under study, 107 subjects were healthy and 50 were suffering
kyphosis. 44 students were carrying hand bags 29 of whom were healthy and 15 of them suffered kyphosis.
62 students used one-sided backpacks 47 of whom were healthy and 15 were suffering kyphosis. 51 students
were carrying backpacks 31 of whom were healthy and 20 were suffering kyphosis. According to the results
2
from table 4, on X test on the relationship between carrying backpacks by primary school students and the
possibility of kyphosis disorder, and considering the 0.217 level of significance, it can be concluded that
there is no significant relationship between carrying backpacks and possibility of kyphosis disorder in high
school girls (P=0.05).
Table 5. description of the percentage of the ratio of backpack weight and the weight of
students divided by school level
variable
Primary school
High school
Ratio of backpack to
10 years <
10- 15
15 >
total
10 years <
10- 15
15 >
total
subject’s weight
Frequency
161
40
12
213
153
4
0
157
Percentage
75.6
18.8
5.6
100
97.5
2.5
0
100
Mean
8.698
6.704
Standard deviation
3.318
1.741
variance
11.006
3.033
18.8% of students in primary schools and 2.5% of students in high school had the ratio of 10 -15 for their
backpack weight and the weight of their body. 5.6% of students in primary schools and 0% of students in
high school had the ratio of over 15 for their backpack weight and the weight of their body. An overall
24.4% of the primary school students had a ratio of backpack weight and the weight of their body which is
much higher compared to the 2.5% of high school students. Mean of the ratio between backpack weight
and the weight of the body in primary school girls was 8.698 and this variable was 6.704 in high school
students. Standard deviation of backpack weight to the weight of students in primary school girls was 3.318
whereas this number was 1.741 in high school girls.
Discussion
Findings of the present study revealed that there is a significant relationship between weight of the
backpack and kyphosis disorder in primary school girls (table 1). This finding concord with findings of
Mohammadi, Dorosti Motlagh et al., and Mackiea and Leeg. They demonstrated that as the ratio of
backpack weight exceeds 10% of student’s body weight, kyphosis possibility increases and pulmonary
capacity decreases. They believed that carrying bags from primary school years imposes negative effects on
skeletal muscular system of students of those schools and its continuance induce physical problems later in
adulthood (Dorostimotlag et al., 2009 & Mohammadi et al., 2012). In the present study, 24.4% of students
carried bags and backpacks weighing more than 10% of their body weight (table 5). Carrying these bags in
primary school years has caused the hypothesis to be significant. Yet, this finding differs from findings of
the studies conducted by Kathleen et al., Ramprasad et al., Zamanian et al., and Rajabi et al., They found
that backpack weight has the greatest impact on shoulder pressures and since primary school children are
in the age of growth, these problems are more serious. Carrying heavy backpacks in childhood causes bad
physical condition in adulthood (Ramprasad et al., 2010). It seems as if weak skeleton of the subjects at early
ages and not being able to carry heavy loads are the main features of this age (Cleiton et al., 2014). Body
organs are still growing and are not strong enough at these ages; therefore, imposing heavy loads in the
growth age will change and even block the epiphysis plate (Chow et al., 2010). Thus, ideal backpacks have
two straps, air cushion and a belt to prevent damages to the shoulders (Mohammadi et al., 2012). Besides,
results from this study revealed that the relationship between backpack weight and kyphosis disorder in
high school girls is not significant (table 2). This finding does not concords with findings from studies by
Xiangrong et al., Al-Khabaz & Shimada, Gray et al., Ramprasad et al., They revealed that heavy weight of the
backpack drops the shoulders and bends the chest box or the back ending in hunch in the back. Yet, the
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findings concord with results from studies conducted by Mihailova et.al. Hussaini et.al. Chow et.al. And
Mostafazadeh. Descriptive results from this study showed that only 2.5% of high school girls carry bags
weighing more than 10% of their body weight (table 2). On the other hand, 67.5% of students in high school
carried one-sided bags that did not have the effects of backpacks (table 4). It seems as if lower weight of the
backpack along with correct carrying methods has caused the hypothesis of the study to be insignificant.
Besides, modern technologies and transportation including car pool may have decreased the negative
effects of backpack weight and ended in contradictory results from this study compared to previous ones
(Hussaini et al., 2012 & Mihailova et al., 2014). Moreover, this study found that there is a significant
relationship between type of carrying bags and kyphosis possibility in primary school girls (table 3). This
findings concord with findings from studies by Norimitsu et al., Tarkeshwar & Michael, Dorosti Motlagh
et.al. Daneshmandi & Hussaini and Daneshmandi et al., They believe that backpacks weighing over 10% of
body weight end in kyphosis (Daneshmandi et al., 2011 & Daneshmandi et al., 2010), negative impact on
bone growth (Tarkeshwar et al., 2009) and lower pulmonary capacity of the individual (Ramprasad et al.
2010). However, this contradicts with findings from studies conducted by Charles et al., Olubayo-Fatirgun
and Hussaini et al., They demonstrated that backpacks weighing over 10% of body weight do not have
significant effects on skeletal condition heart rate, blood pressure, calorie usage and pulmonary ventilation
(Charles et al., 2014 & Olubayo-Fatiregun et al., 2014). It seems as if the reason for this contradiction is the
lower weight of backpacks and different lifestyles the subjects had. In this regard, 67.6% of subjects used
backpacks (tables 3 & 4) and since at early ages the body tends to bend forward, upper limbs bend forward
as well and as a result kyphosis emerges gradually (Daneshmandi et al., 2011 & Haselgrove et al., 2008).
Results revealed that there is no significant relationship between type of carrying backpack and popsibility
of kyphosis disorder in high school girls (table 4). This finding contradicts with findings from studies by
Dorosti Motlagh et al., Olubayo-Fatiregun et al., Al-Khbaza and Shimada, Mohan et al., And Chow et al.,
They believe that carrying backpacks weighing more than 10% of the body weight ends in kyphosis
(Norimitsu et al., 2014 & Chow et al., 2006). It seems as if using one-sided backpacks (67.5%) and lightweight backpacks compared to students’ body weight in high school (6.704) are the reasons for lack of
relationship between carrying bags and kyphosis in high school students (table 4). Another important point
at this age is that students try to keep up their appearances and therefore change their bags from hand to
hand or shoulder to shoulder constantly and do a lot of physical exercises to keep up with their peers in
their physical fitness (Dadban et al., 2013) and they hinder the process of kyphosis (Daneshmandi et al.,
2010 and Rajabi et al., 2008).On the ratio of weight carried by students and their weights, did the study find
that mean of this ratio in primary school and high school is 8.729 and 6.407 respectively (table 5). This
finding concord with findings of Alaf et al., Amal et.al. Daneshmandi & Hussaini, Hussainin et al., (2012 A &
B). They demonstrated that primary school children carry heavier bags in relation to their body weight
(Amal, 2012 & Altaf et al., 2014). Furthermore, the present study found that 24.4% of students carried bags
weighing more than 10% more weight compared to their body weight (table 5). Nevertheless, researches by
Hussaini et al., Revealed 9.5 and 11% to be the ideal and maximum extra weight compared to the body
weight in primary school years. This finding concords with findings of Hussaini et al., (2012 A & B) and
Daneshmandi et al., Who calculated the national norm for primary schools to be 9.5 to 11% or 2.10 to 3.90 kg
and for high schools to be 7 to 8.5% or 4.25 to 5.60 kg. Unlike this study, Ramprasad et al., and
Daneshmandi et al., Suggested maximum weight for primary school students to be 7.5 to 8% of the body
weight (Daneshmandi et al., 2010 & Ramprasad et al. 2010). Accordingly, results from the present study
show that primary school girls carry bags heavier than national standard weight for families normally tend
to load them with food and refreshment in order not to use the cafe at school (Mohan et al., 2007). On the
other hand parents and teachers may give general homework from whole books forcing students to carry all
their books in their bags whereas high schools have lighter expectations of this kind from their students
(Lafond et al., 2007). Findings from this study also demonstrate that average length of time primary school
and high school girls carry are 8.79 and 5.36 minutes respectively. Whereas Daneshmandi et.al. Reported
that numbers to be 10.5, 14.5 and 19.45 for primary school, secondary school and high school students
respectively. The reason for this significant difference in results from these studies may be using modern
technologies like car-pooling (Salehzadeh et al., 2011) and other transportation facilities like family cars
(Kathleen et al., 2014) along with social features and close distance of schools to homes (Mihailova et al.,
2014).
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Conclusion
Considering the results, a high percentage of girl students (20.2% primary school and 31.8% of high school
girls) suffer kyphosis. On the other hand, heavy weight of the backpacks (Primary schools 8.896 kg and
high schools 6.407 kg) and the length of carrying backpacks (8.79 minutes for primary schools and 5.36
minutes for high schools) along with weak physical fitness due to carpooling and family cars are among all
social conditions worsening condition of kyphosis disorder in female students.
Suggestions
Holding workshops and offering courses on the reasons of disorders and necessity of physical fitness and
improving methods for students, their parents and teachers on biomechanical principles, weight and
organization of staff in the backpack are all of great importance. On the other hand mass media including
TV, Radio, newspapers and other magazines and journals have to try to raise awareness on correct carrying
habits and physical disorders.
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