• Child Health Nursing Research
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• v.14 no.2
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• pp.176-185
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• 2008

Purpose: The purposes of this study were to investigate extent of backpack use and incidence of musculoskeletal pain, and to identify the relationship between backpack use and musculoskeletal pain. Method: A descriptive correlational study was conducted in one elementary school and one middle school in D city. Participants were 273 children, aged 12-14, who completed a self-administered questionnaire. Body weight, height, and backpack weight of participants were measured. Results: Mean backpack weight was 3.78 Kg and relative backpack weight (RBW) was 7.42%. Of backpack users, 23.8% carried more than 10% of their RBW and 9.2% carried more than 15%. Only 44.3% organized the contents in their backpack correctly. For more than three fourth of the students (76.2%), the bottom of backpack in the standing position drooped more than 10 cm below the waistline, and 46.3% complained of musculoskeletal pain. Use of a waist belt was significantly related to musculoskeletal pain. Conclusions: A considerable proportion of school children were not following guidelines for safe backpack use. Although the relationship between backpack use and musculoskeletal pain in this study was not significant, the fact that 46.3% of the students experienced musculoskeletal pain is very meaningful information. Further research is required to identify the risk factors of musculoskeletal pain among children.

• Physical Therapy Korea
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• v.27 no.1
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• pp.45-52
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• 2020

Background: A backpack is available equipment for moving some objects. Most studies have found that the appropriate weight limit of backpack for students is between 10% to 15% of their body weight (BW). However, Some students should carry a backpack heavier than 15% of BW. Therefore, It is associated with abnormal shoulder and neck posture on students. Objects: This study tested the effects that various amounts of weight carried by university students in their backpacks had on their cervical posture and electromyography of neck muscle. Methods: The subjects consisted of 12 students (6 male, 6 female) in university. There were three loading conditions tested: no backpack, a backpack that weighed 10% and 15% of the student's BW. The dependent variables were the craniovertebral angle (tragus to C7) and the neck muscle activities (sternocleidomastoid, upper trapezius). All 12 subjects were asked to walk while wearing a backpack for 5 minutes and were then instructed to rest for 2 minutes. Results: When assessing the craniovertebral angle, the results of this study were significantly decreased in the order of 0%, 10%, and 15%. And then, there were significantly increased electromyography of neck muscles that comparison of the weight of 10% and 15% on 0%. It was found that as the weight of the backpack increased, the craniovertebral angle decreased (p < 0.05) and the muscle activities increased (upper trapezius p = 0.012, sternocleidomastoid p = 0.013). Conclusion: Our study recommended that some students shouldn't carry on over the 15% backpack of own weight, and also they should distribute backpack load to equal on body for optimal posture.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.35-40
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• 2006

The purpose of this study was to investigate the relationships between weights of backpack and back and shoulder pains of elementary school students in Korea. A cross-sectional sample of 278 boys and 233 girls aged between 7 and 12 years were analyzed for this study. 49.1% of the participated children reported their backpacks were felt heavy, and the weights of their backpack were grater than 13.3% of their body weight. About 65.4% of students carried greater than 10% of their body weights. The weight of the backpack showed significant positive relationship with shoulder pain but not with their back pain. The results of this study suggested that overweighed backpack could cause the musculoskeletal pain to the elementary school students. Therefore, an effective backpack safety program for parents and students is necessary to educate them how to prevent possible musculosketal pain related to the weight of backpack within the perspective of the ergonomical approach.

• Journal of Korean Physical Therapy Science
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• v.18 no.4
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• pp.81-85
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• 2011

Purpose : The purpose of this study was to investigate the changing plantar foot pressure by the backpack load of 0, 10, 15, and 20% of their body weight while level walking in flat foot and so to recommend suitable backpack weight limitations for flat foot subjects. Method : 14 young flat foot subjects($24.29{\pm}2.16yrs$) participated in this study. the subjects were assigned to carry backpack load and there was four level walking modes : (1) unloaded walking(0%), (2) 10% body weight(BW) load, (3) 15% BW load and (4) 20% BW load. Repeated ANOVA was used to compare each region data of foot according to different backpack weight. Results : As backpack load became increased, the contact area of midfoot was significantly increased, and contact area of forefoot and rearfoot were significantly decreased. maximum pressure at each region during walking tended to be greater as the load increased, but a significant difference was found only for the heel medial and lateral regions Conclusion : Based on this data, the weight of backpack could influenced structure and function of the foot in flat foot.

• Fashion & Textile Research Journal
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• v.12 no.3
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• pp.364-371
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• 2010

The purpose of this study is to weigh the students' backpacks of middle school in daily use and to analyse their physiological responses and subjective senses when carrying backpack in order to promote healthy and comfort school life of girl middle school students. Two female students were subjects who answered the questionnaires on two types of backpack and their metabolism, perspiration and the changes of skin temperature were measured in constant environment chamber, $25{\pm}1$ and $49{\pm}10$% RH. They walked on the treadmill carrying the backpack with the increment of backpack weight, 2 kg, 4 kg to 6 kg. When the backpack increases to 6 kg, the discomfort parameters and responses increases rapidly. Comparing with general type, improved type of backpack showed good results in physiological responses, but not in subjective senses, such as the ease of movement, pain, or total preference, specially in 2 kg and 4 kg. The girl students prefer the general type of backpack which is of fashion and small, when it weighs light such as 2 kg or 4 kg, while they prefer the improved bag which is functional when it is heavy as 6 kg. The longer wearing time of the medium weight, for example, 4 kg without feeling or recognition of any discomfort due to fashion style, might cause the students' posture and health weaker or more vulnerable to the problems.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.1
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• pp.33-43
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• 2013

Purpose : The study was designed to identify the change of body alignment according to surface during walking with backpack. Methods : Healthy twenty people(10 men & 10 women) participated in this study. The exclusion criteria were orthopedic and neurologic disease. Initial alignment measurements were performed. Results were evaluated by angle and range from earlobe to acromion, acromion to malleolus and earlobe to malleolus in the GPS system. Results : On the hard surface, the distance and angle from malleolus to earlobe increased after walking with backpack which is 20 % of weight(p<.05). In addition the distance from malleolus to acromion and the angle from earlobe to acromion increased(p<.05). On the soft surface, on the other hand, the distance and angle from malleolus to earlobe decreased after walking with backpack which is 20 % of weight(p<.05). There was no relationship between the change of the surface and the body's alignment(p>.05). Conclusion : Consequently, the body alignment was changed by backpack which is 20 % of weight, but body alignment wasn't changed by the surface. So more study need to be surveyed regard of this.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.191-198
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• 2015

Objective : The purpose of this study was to conduct biomechanical analysis of varying backpack loads on the lower limb movements during downhill walking over $-20^{\circ}$ ramp. Method : Thirteen male university students (age: $23.5{\pm}2.1yrs$, height: $175.7{\pm}4.6cm$, weight: $651.9{\pm}55.5N$) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked over $20^{\circ}$ ramp with four different backpack weights (0%, 10%, 20% and 30% of body weight) in random order at a speed of $1.0{\pm}0.1m/s$. Five digital camcorders and two force plates were used to obtain 3-d data and kinetics of the lower extremity. For each trial being analyzed, five critical instants were identified from the video recordings. Ground reaction force, loading rate, decay rate, and resultant joint moment of the ankle and the knee were determined by the inverse dynamics analysis. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among four different backpack weight conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results : The results of this study showed that the medio-lateral GRFs at RHC in 20% and 30% body weight were significantly greater than the corresponding value in 0% of body weight. A consistent increase in the vertical GRFs as backpack loads increased was observed. The valgus joint movement of the knee at RTO in 30% body weight was significantly greater than the corresponding values in 0% and 10% body weight. The increased valgus moment of 30% body weight observed in this phase was associated with decelerating and stabilizing effects on the knee joint. The results also showed that the extension and valgus joint moments of the knee were systematically affected by the backpack load during downhill walking. Conclusion : Since downhill walking while carrying heavy external loads in a backpack may lead to excessive knee joint moment, damage can occur to the joint structures such as joint capsule and ligaments. Therefore, excessive repetitions of downhill walking should be avoided if the lower extremity is subjected to abnormally high levels of load over an extended period of time.

• Journal of Korean Physical Therapy Science
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• v.25 no.2
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• pp.7-14
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• 2018

Purpose: This study was conducted to analyze the effect of bag type on gait kinematic factors. The purpose of this study was to compare the Cobb's angle, leg angle and foot pressure difference according to bag type among 20 university students. Methods: The bag type was applied with two kinds of bags: not wearing a bag, backpack, and an eco bag. The bag weight was 10% of subjects weight in during experiment and only bag weight was 0.5kg. Results: Knee joint angle is increased when wearing backpack or an eco bag than not wearing bag. Cobb's angle increased when wearing backpack and wearing eco back. The difference in right and left foot pressure increased when wearing eco bag than not wearing bag and wearing backpack. Conclusion: Therefore, wearing a heavy backpack or an eco bag when walking for a long time may cause scoliosis and change the walking form.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.110-116
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• 2000

The soft drink deliveries are made for a broad line of soft drink products by using a hand truck and the backpack mode of carriage. The workers usually deliver the beverages by backpack mode of carriage, because they feel safe with such a carrying method in stairways. In this study, the physiological workload of backpack carrying was investigated, especially focused on the effects of weight of load and carrying by the stairway. A laboratory experiment was conducted to measure heart rate and oxygen uptake during backpack carrying tasks, and an ergonomic guideline was proposed for such type of task based on the results of the experiment. Eight healthy male subjects performed the backpack carrying of 40kg and 60kg, (1) on the level ground, (2) upstairs and (3) downstairs. The result showed that the stairways caused the increased physiological cost, and that a carrying load of 60kg required significantly higher physiological cost as compared to carrying 40kg. Although backpack carrying has some advantages in the biomechanical aspect, it should be advised to carry a load of less than 40kg, since the task requires a very high physiological cost. During backpack carrying, it is also recommended for a delivery person to make more trips with a light load rather than to make less trips with a heavier load at one trip.

• Journal of Biomedical Engineering Research
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• v.42 no.5
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• pp.225-231
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• 2021

The purpose of this study was to investigate the effect on the activity of the upper trapezius and erector spinae according to the length difference of the backpack using electromyogram (EMG). We also conducted a study comparing the center of pressure (COP) and weight distribution before and after using Wii® balance board. Thirty individuals were randomly assigned to the experimental group (n=14) wearing a backpack with a short right strap length and a control group (n=16) wearing a backpack with the same strap length. Data were collected by dividing into groups, carring a 15% weight backpack and walking for 20 minutes on a treadmill. As a result of analyzing the EMG data, there was no significant change in the upper extremity muscle activity of the control group, but it was significantly decreased in the right upper trapezius activity of the experimental group (p<0.05). In addition, there was a significant change of COP in the experimental group (p<0.05), but there was no significant difference of the weight distribution in both groups. Recognizing mechanical changes in the body that may occur due to the asymmetry of the strap length is thought to be helpful for systematic ergonomic intervention according to changes in the external environment in the future.