• 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.

• 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.

• 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.

• 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 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.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.8
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• pp.1179-1189
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• 2008

The purpose of this study is to investigate the satisfaction of the adolescents' school backpack bag and the important criteria when purchasing for developing comfort and functional backpack. The questionnaire was composed and surveyed with 245 middle school students and the data were analyzed through SPSS 13.0. Purchasing criteria were grouped into 5: practical, shop environment, comfort, aesthetic and maintenance. Satisfaction factors were function/comfort, fashion/aesthetic and durability/A.S. 50.2% of students recognized the inappropriate wearing backpack might cause the deformation of body shape. And the wrong habit of wearing bag was found to affect the body posture of students. Main symptoms caused by wearing it for long time are ‘sweating around shoulder and back' and ‘feeling stiff in shoulders and waist'. Needs arise to develop the bag which could prevent them and to educate students how to wear bags. According to the result from MDS of purchasing criteria, one axis is product vs. environment, and other is functional vs. psychological aspects. According to the result from MDS of bag satisfaction, one axis is function/durability vs. fashion/appearance, and other is gestalt quality vs. part quality. They wanted the improvement in the aspects of shape/design, material, maintenance, comfort and usability of the bags. Specially it is required that we research the adolescent customer-oriented way and develop the new materials or shapes pursuing both shoulder comfort and characteristics.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.143-146
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• 2001

Background : Backpack palsy was described in military personnel with shoulder girdle and proximal upper extremity symptoms, predominantly motor in nature related to the use of heavy backpack. Currently, backpack were used for sports, transporting school books and child carriers. We evaluated clinical and electrophysiological feature of backpack palsy. Methods : We included 11 patients with brachial plexopathy as a result of wearing a heavy backpack on long distance marches. All patients were done routine blood sampling, chest X-ray, C-spine X-ray and electrophysiological studies. Results : All patients were right handed person and were not as having a thoracic outlet syndrome. Sensory changes were main initial symptoms and major persistent symptoms were motor weakness. 9 patients(81.8%) were damaged the brachial plexus on non-dominant side, 1 patient was dominant and 1 patient was bilateral involvement. 10 patients(90.9%) were damaged to upper trunk of the brachial plexus by EMG findings. The prognosis was good, 10 patients(90.9%) were complete recovery during 8 weeks, 1 patient was developed reflex sympathetic dystrophy confirmed by 3-phase bone scan. Conclusions : Depression of the clavicle and costoclavicular space probably plays a certain role in pathogenic mechanism. The non-dominant side is more frequently affected, probably due to underdevelopment of the musculature in that side.

• 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.

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.899-902
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• 2005

언제, 어디서, 누구나 대용량 네트워크를 사용할 수 있는 유비쿼터스(ubiquitous) 시대가 다가오면서, 카메라가 장착되어 있고 무선 통신이 가능한 PDA, 웨어러블(wearable) 컴퓨터와 같은 휴대용장치가 가까운 미래에는 일상의 한 부분이 될 것이다. 이런 상황을 반영하듯, 휴대용 장치를 이용하여 실감형 게임(augmented game)을 수행하는 다양한 연구가 진행되어 왔다. 기존의 실감형 게임들은 전통적인 ‘backpack’ 시스템을 이용하거나 패턴마커(pattern marker)를 이용하였다. ‘backpack’ 시스템은 비싸고, 거추장스러우며, 사용하기 불편한 단점을 가지고 있으며, 패턴마커를 이용하면 미리 정한 장소에서만 게임을 즐길 수 있는 단점을 가지고 있다. 본 논문에서는 Flying Cake이라는 실감형 게임을 소개하며, 거추장스러운 장비 대신, 가볍고 휴대 가능한 PDA를 이용하여 게임을 수행하며, 실제 세계에서 가상의 물체를 접목할 위치를 지정하기 위해, 미리 정해져 있는 패턴마커 대신 얼굴 영역을 이용한다. Flying Cake은 연산자원이 부족한 PDA에서 실시간으로 얼굴 영역을 찾기 위해 스킨칼라(skin-color) 모델과 CAMShift 알고리즘을 이용하며, PDA상에서 카메라를 이용하여 실제 세계와 가상의 물체 사이의 상호작용을 제공하는 새로운 게임 패러다임(paradigm)을 통해 사용자에게 새로운 즐거움을 제공한다.