Effects of Backpack Types on Kinematics and Plantar Pressure in College Students During Stairs Walking / 医用生物力学

Objective To analyze the influence of different backpack types and loads on kinematics and plantar pressure of college students during stair climbing, so as to provide references for choosing the appropriate backpack and carrying mode. Methods The Nokov infrared light point motion capture system and Podome plantar pressure system were used to analyze the differences in the range of motion ( ROM) of the trunk and lower limb joints, the kinematic parameters at the peak time, the peak pressure of each plantar partition, the contact time, the maximum pressure of the whole foot, the average pressure and the maximum contact area for 15 male college students during the support period of stair climbing. Results The 5% BW and 10% BW backpack loads reduced ROM of trunk rotation, increased ROM of ankle flexion/ extension and varus / valgus. The 10% BW backpack loads increased the peak pressure of the 1st and 3rd metatarsals bones and the maximum pressure of the whole foot ( P < 0. 05). Single-shoulder bag and handbag reduced ROM of trunk tilting and rotation, and increased ROM of ankle flexion and extension, hip flexion angle, peak pressure of foot arch and medial heel (P<0. 05). The double-shoulder bag loads increased peak pressure in the toe area (P<0. 05). Conclusions During walking on the stairs, the 5% BW and 10% BW backpack loads limited trunk rotation and increased ankle ROM. The 10% BW loads also increased the load in metatarsal area. The unilateral weight-bearing mode would make the trunk tilt to the unload side and rotate to the weight-bearing side. The pressure in toe area was higher when carrying double-shoulder bag, while single-shoulder bag and handbag mainly increased the pressure of arch foot and medial heel. It is suggested that college students choose symmetrical backpack scheme, and wisely allocate back weight to avoid the injury of foot area.

Análisis del peso de las mochilas en estudiantes de enseñanza básica: estudio de corte transversal / Analysis of the weight of backpacks in basic education students: cross-sectional study

INTRODUCCIÓN: La mayoría de los establecimientos educacionales tienen una jornada escolar completa, generando que el estudiante transporte mayor cantidad de útiles escolares en su mochila. OBJETIVO: Analizar el peso promedio de las mochilas de espalda en estudiantes de educación básica de la comuna de Copiapó. METODOLOGÍA: se realizó un estudio descriptivo de corte transversal con alcance correlacional, la muestra estuvo constituida por 286 estudiantes (139 varones y 147 mujeres) de educación básica, de un establecimiento escolar de la comuna de Copiapó. Se analizó el peso corporal, la altura y el peso de las mochilas durante una semana, mediante una plataforma de fuerza y estadiómetro. RESULTADOS: Se encontró que entre los días lunes a jueves los estudiantes llevaban en su mochila un peso que sobrepasaba el 10/ de su peso corporal. Asimismo, las mochilas de espaldas son las más utilizadas en comparación con las mochilas con ruedas, con un 88,1% de la muestra. Sin embargo, las mochilas de espalda presentaron menor peso al compararlas con las mochilas con ruedas, las cuales tuvieron valores cercanos al 20% del peso corporal. CONCLUSIÓN: La mayoría de los estudiantes transportaban en sus mochilas, pesos que superan el 10% de peso recomendado, siendo las mochilas con rueda las de mayor peso. Se recomienda desarrollar normas establecidas dentro de los colegios, para evitar el traslado de dichas cargas y prevenir alteraciones posturales, biomecánicas y fisiológicas.

INTRODUCTION: Most educational establishments have a full school day, causing the student to carry a greater number of school supplies in their backpack. OBJECTIVE: To analyze the average weight of backpacks in basic education students of the Copiapó district. METHODOLOGY: a descriptive cross-sectional study with correlational scope was carried out, the sample consisted of 286 students (139 men and 147 women) of basic education, from a school in the district of Copiapó. Body weight, height and backpack weight were analyzed for one week, using a force platform and stadiometer. RESULTS: It was found that between Monday and Thursday the students carried a weight in their backpack that exceeded 10% of their body weight. Likewise, backpacks on the back are the most used compared to backpacks with wheels, with 88.1% of the sample. However, the backpacks presented less weight when compared to the backpacks with wheels, which had values close to 20% of body weight. CONCLUSION: Most of the students carried weights in their backpacks that exceed 10% of the recommended weight, with wheeled backpacks being the heaviest. It is recommended to develop established norms within the schools, to avoid the transfer of said loads and prevent postural, biomechanical and physiological alterations.

Kinematic analysis and self-perceived exertion during the walking gait with a backpack in Brazilian scholars

Abstract Aim: The present study aimed to investigate the effects of different backpack loads on the walking gait kinematics and ratings of perceived exertion (RPE) in Brazilian scholars. Methods: The sample was composed of 25 male children and adolescents, from 10 to 14 years. The mean body mass and height were 45.3 kg ± 10.6 kg and 1.51 m ± 0.08 m, respectively. For the walking gait assessment, a tridimensional analysis system was used. In the backpack conditions, loads of 5%, 10%, 15%, and 20% were applied according to the body weight of everyone. Kinematic variables and angular amplitudes of head, shoulders, thorax, pelvis, and knees in the sagittal plane were collected. The OMNI scale was used to assess the RPE. Results: The loads of 5%, 10%, 15%, and 20% promoted postural adjustments and alterations in the walking gait, in which the RPE presented a correlation with those alterations. The step in the left cycle altered from the baseline in the 5% (p = 0.006). The stride length altered from baseline in the 5% (p = 0.030) and 10% (p < 0.001) load conditions. The single support time was different from baseline in all conditions (p = 0.003; p = 0.012; p = 0.005; p = 0.006). The walking gait cadence was different in the comparison between baseline in the 5% (p = 0.003). Thorax amplitude altered in the 10% (p = 0.023), 15% (p = 0.033) and 20% (p = 0.005) load conditions in the left cycle. Conclusion: We concluded that the posture, RPE, and the gait kinematic altered according to the increase in the backpack load.

Evaluation of Optimal Gravity Center Position of Backpack in Half-Squat Parachuting Landing / 医用生物力学

Objective To study effects of backpack gravity center position on kinetics and kinematics of lower-extremity joints in parachuting landing and evaluate the injuries. Methods Seven participants performed parachuting landing with backpack gravity center on three positions: low-back (position 1), upper-back (position 2) and abdomen (position 3). Results The peak vertical ground reaction force (GRF) with backpack on position 2 was significantly lower than that on position 1. The joint moment on sagittal plane of the hip with backpack on position 2 was significantly higher than that on position 1 and position 3. The joint energy absorption of the hip with backpack on position 2 was significantly higher than that on position 1. The angular displacement of the hip on sagittal plane with backpack on position 2 was significantly higher than that on position 1 and was significantly lower than that on position 3. The angular velocity of the hip on sagittal plane with backpack on position 2 was significantly lower than that on position 3. Conclusions Different positions of backpack gravity center could significantly influence kinetic and kinematic parameters of the hip. Backpack gravity center on upper-back position could decrease the lower-extremity injuries. The results can provide evidences for evaluating backpack gravity center and decreasing injuries in parachuting landing.

Unusual Suicide Cases of Asphyxiation by Ligature within the Vehicle / 대한법의학회지

One of the most common methods of suicide is hanging, and suicide by ligature strangulation is quite rare. Vehicles have a confined space, making them an unusual place for committing suicide by hanging or ligature strangulation, because they are more typically the location of suicide by carbon monoxide intoxication by briquette or drug intoxication. Here, we present three cases of unusual suicide by ligature strangulation, discuss the mechanism of asphyxia in each case, and review the literature. In case 1, the victim used a backpack to perform reverse hanging by wrapping the shoulder strap of the backpack around his neck and then tossing the backpack behind the backrest of the driver's seat. In case 2, the victim did not use the internal structures of the vehicle, but pulled down on a ligature wrapped around both his knees and neck. In case 3, the victim hanged himself using a package line fixed to the roof handle grab of the back passenger seat.

Quality of life, school backpack weight, and nonspecific low back pain in children and adolescents / Qualidade de vida, peso das mochilas escolares e lombalgia não específica em crianças e adolescentes

OBJECTIVES: To describe the degree of disability, anthropometric variables, quality of life (QoL), and school backpack weight in boys and girls aged 11-17 years. The differences in QoL between those who did or did not report low back pain (LBP) were also analyzed. METHODS: Eighty-six girls (13.9 ± 1.9 years of age) and 63 boys (13.7 ± 1.7 years of age) participated. LBP was assessed by questionnaire, and disability using the Roland-Morris Disability Questionnaire. QoL was assessed by the Pediatric Quality of Life Inventory (PedsQL). Multivariate analyses of variance and covariance were used to assess differences between groups. RESULTS: Girls reported higher disability than boys (p = 0.01), and lower QoL in the domains of physical (p < 0.001) and emotional functioning (p < 0.01), psychosocial health (p = 0.02) and physical health summary score (p < 0.001), and on the total PedsQL score (p < 0.01). School backpack weight was similar in both genders (p = 0.61) and in participants with and without LBP (p = 0.15). After adjustments, participants with LBP reported lower physical functioning (p < 0.01), influencing lower physical health summary score (p < 0.01). CONCLUSIONS: Girls had higher disability and lower QoL than boys in the domains of physical and emotional functioning, psychosocial health, and physical health summary scores, and on the total PedsQL score; however, similar school backpack weight was reported. Participants with LBP revealed lower physical functioning and physical health summary score, yet had similar school backpack weight to those without LBP. .

OBJETIVOS: Descrever o grau de incapacidade, as variáveis antropométricas, a qualidade de vida (QV) e o peso das mochilas escolares em meninos e meninas com 11-17 anos. Também são analisadas as diferenças na QV entre os que relataram ou não lombalgia (LBP). MÉTODOS: 86 meninas (13,9 ± 1,9 anos) e 63 meninos (13,7 ± 1,7 anos) participaram. A LBP foi avaliada por um questionário e a incapacidade pelo Questionário Roland-Morris. A QV foi avaliada pelo Questionário Pediátrico sobre Qualidade de Vida (PedsQL). As análises de variância e de covariância multivariadas foram usadas para avaliar as diferenças entre os grupos. RESULTADOS: As meninas relataram maior incapacidade do que os meninos (p = 0,01) e menor QV nos domínios de funcionamento físico (p < 0,001) e emocional (p < 0,01), no escore sumário de saúde psicossocial (p = 0,02) e saúde física (p < 0,001) e no escore total no PedsQL (p < 0,01). O peso das mochilas escolares era semelhante para ambos os sexos (p = 0,61) e para os participantes com e sem LBP (p = 0,15). Após ajustes, os participantes com LBP relataram menor funcionamento físico (p < 0,01), o que influenciou um menor escore sumário de saúde física (p < 0,01). CONCLUSÕES: As meninas tiveram maior incapacidade e menor QV do que os meninos nos domínios de funcionamento físico e emocional, nos escores sumários de saúde psicossocial e física e no escore total no PedsQL; contudo, foi relatado um peso semelhante das mochilas escolares. Os participantes com LBP revelaram menor funcionamento físico e escore sumário de saúde física, mesmo carregando mochilas escolares de mesmo peso do que aqueles sem LBP. .

THE WEIGHT OF SCHOOLBAGS AND MUSCULOSKELETAL SYMPTOMS IN SCHOOL STUDENTS, ULAANBAATAR, MONGOLIA / Шинэ санаа Шинэ нээлт

There is a little information about weight excess of school materials in Ulaanbaatar, Mongolia. The aim of this study was to study of the weight of backback and the ergonomic effects of backpack carriage on school students in Ulaanbaatar. This cross-sectional study was performed in the city of Ulaanbaatar in 2015. Two hundred fourteen school students participated in study. Nordic Musculoskeletal Questionnaire was used, asking about complaints of neck, shoulders, upper and lower back. Length and weight of the children were determined. Backpacks were weighed and the relative weight of the backpack was calculated.In this study, first and second grades students carried proportionately heavier backpacks than older students and more than 10% of their weight. Musculoskeletal complaints were reported by about 79% of school students. The (relative) weight of backpacks was not related to complaints of neck, shoulders, upper and lower back.

Effects of different load distribution modes on human physiological parameters during walking / 医用生物力学

Objective To investigate the effects of unevenly-distributed backpack loads on human physiological parameters as compared to the traditional centrally-placed load at the backpack bottom. Methods For the unevenly-distributed load mode, the backpack was divided into four spaces including top right, top left, bottom right and bottom left. The loads were divided into two parts proportionally (1/2∶1/2, 1/4∶3/4 and 3/4∶1/4) and placed at the bottom left and top right of the backpack, respectively. The remaining two spaces were filled with the plastic foam. Ten healthy volunteers performed 30-min walking trials on the treadmill at the speed of 1.1 m/s with the backpack load equal to 10% body weight (BW). The changes of subjects’ body posture, muscle fatigue, heart rate, blood pressure before and after the trial, as well as the electromyography (EMG) changes at 0, 5, 10, 15 min after the trial were measured by the Bortec AMT-8 and the NDI Optotrak Certus. Results The muscle fatigue of right upper trapezius and forward-leaning angle increased as the loads at top right of the backpack increased. However, the muscle fatigue in the new mode of backpack load distribution showed no significant differences as compared to the traditional mode under the same backpack loads. The new mode with the load ratio of 3/4∶1/4 had no significant effects on posture. The new mode with the load ratio of 1/2∶1/2 could contribute to the decrease of heart rate and blood pressure as compared to the traditional mode. Conclusions Adopting a new and more reasonable load distribution mode can guarantee the body posture unaffected by the backpack loads, and decrease heart rate and blood pressure. Therefore, the cross and evenly distributed load mode is recommended for the backpack design.

Development and application of modular handling platform for field medical chest or backpack / 医疗卫生装备

To develop a handling platform for loading, unloading, fixation, deployment, withdrawal and etc of medical materials in field conditions. Classified handling was performed for different function units with the de-vice developed, which was composed of a trolley, a railroad, a hydraulic handling board, a fixation belt and a vehicle-mounted tractor. The platform could enhance the efficiency of materials handling, which behaved well in the hos-pital without any handling device. The modular handling platform is easy to unload, carry, transport, fix and maintain, and thus is worthy popularizing practically.

Kinetics analysis on gait termination for children with backpacks / 医用生物力学

Objective To understand kinetics characteristics of gait termination for children with backpacks， and compare the difference between planned gait termination (PGT) and unplanned gait termination (UPGT) as well as effects of backpack carrying by children at the moment of gait termination. Methods Twelve boys (age (9.85±1.34) years old, height (140.89±11.57) cm, weight (34.96±9.62) kg) were recruited in this study. The gait termination scene in real life was simulated in the lab by the subjects who were required to carry different backpacks, while the parameters of ground reaction force and center of pressure (COP) during PGT and UPGT were recorded by two 3D force plates. Results There were significant differences in the peak ground reaction force curve between gait termination and normal walking. Meanwhile the peak ground reaction force and COP shifting during PGT and UPGT were both significantly larger than those during normal walking， and the values were increased with the increase of backpack load. The maximum ground reaction force and COP shifting were found during UPGT while the subject was carrying backpack equal to 15% of the body weight (15% BW). Conclusions The change of ground reaction force was useful for gait termination，but children will suffer much more impact force during both PGT and UPGT, and make the control on postural balance more difficult, which could be dangerous with the increase of backpack load. It is advised that children should lighten their backpack loads, which will be helpful to prevent accidental injuries during suddenly external disturbance.

Transporte do material escolar por escolares da rede municipal de ensino fundamental de Porto Alegre - RS / School supplies transportation for municipal elementary school children in Porto Alegre - RS

Transportar carga é uma ação realizada diariamente por todos os escolares. Mochilas, bolsas, pastas são as formas mais comuns observadas. Alguns desses equipamentos favorecem a manutenção de uma postura adequada, especialmente da coluna vertebral, outros, nem tanto. Além do meio como o material é transportado, seu peso (≥10% do peso corporal) é uma variável que pode interferir no deslocamento do centro de gravidade e na flexão do tronco. A associação de flexão da coluna e transporte de carga pode ser um fator desencadeante de patologias da coluna vertebral. O objetivo deste estudo foi verificar a forma como os escolares da Rede Municipal de Ensino Fundamental de Porto Alegre transportam o material escolar, bem como o peso transportado. Este é um estudo descritivo-exploratório transversal. A amostra foi composta de forma aleatória por 430 escolares, estratificados (faixa etária e sexo) pelas quatro regiões administrativas da cidade. Os participantes foram fotografados com o seu material escolar e foram pesados com e sem esses equipamentos. A diferença de peso serviu para identificar o peso transportado. Observou-se que os participantes utilizam majoritariamente a mochila nas costas com apoio sobre os dois ombros para a realização dessa tarefa, não havendo diferença entre meninos e meninas ou entre as faixas etárias. Esses resultados são equivalentes aos encontrados em estudos realizados com outras populações. Foi observado também que o peso médio do material escolar foi de 5,46% do peso corporal, sendo que 8,5% dos participantes transportavam mais de 10% do peso corporal. Esses resultados são inferiores aos observados em outros estudos com outros grupos. Apesar de valores inferiores aos dados internacionais, ações no âmbito da comunidade escolar devem ser realizadas com o objetivo de propor alternativas para diminuir a prevalência de escolares transportando uma carga que pode ser nociva a sua saúde.

Carrying a load is action taken daily by all students. Backpacks, purses, briefcases are the most common forms observed. Some of these items help to maintain a proper posture, especially the spine, others less so. In addition, its weight (≥ 10% of body weight) is a variable that can interfere with the displacement of the center of gravity and trunk flexion. The association of spinal flexion and heavy load can be a triggering factor for diseases of the spine. The objective of this study was to determine how the students of the Municipal Elementary School in Porto Alegre carry school supplies, as well as the weight carried. This is a cross-sectional descriptive exploratory study. The sample consisted of 430 participants randomly stratified (age and sex) by four administrative regions of the city. The participants were photographed with their school supplies and were weighed with and without the equipment. The weight difference was used to identify the weight carried. It was observed that the participants mainly use the backpack with support on both shoulders to this task, with no difference between boys and girls or between age groups. These results are equivalent to those found in studies of other populations. It was also observed that the average weight of school supplies was 5.46% of body weight, and 8.5% of participants carried over 10% of body weight. These results are lower than those observed in other studies with other groups. Eventhough these results are lower than international data reported, actions within the school community should be conducted in order to propose alternatives to reduce the prevalence of students carrying a load that can be harmful to your health.

Effect of Backpack Weight on Postural Angles in Preadolescent Children.

Background: Carrying heavy backpacks could cause a wide spectrum of pain related musculoskeletal disorders and postural dysfunctions. Objective: To determine the changes in various postural angles with different backpack weights in preadolescent children. Design: Cross-sectional. Participants: Healthy male school-children (n=200), mean (SD) age: 12.5 (0.5) years, from high schools in Mangalore, India. Measurements: Bodyweight and height were measured using a forceplate and stadiometer, respectively. From the weight recorded, 5%, 10%, 15%, 20%, and 25% of the bodyweight were calculated and implemented as their respective backpack loads. The Image Tool version 3.0, digitizing software was used for analyzing photographs to determine craniovertebral (CV), head on neck (HON), head and neck on trunk (HNOT), trunk and lower limb angles. Postural angles were compared with no backpack and with backpacks weighing 5% to 25% of the subject’s bodyweight. Results: The CV angle changed significantly after 15% of backpack load (P <0.05). The HON and HNOT angles changed significantly after 10% of backpack load (P <0.05). The trunk and lower limb angle also changed significantly after 5% of backpack load (P <0.05). Conclusions: Carrying a backpack weighing 15% of body weight change all the postural angles in preadolescent children.

The Relationship between Weight of Backpack and Backpain in Primary School Children in Korea

OBJECTIVE: To investigate school children's backpack loads, its association with backpack loads and backpain, school-children's perception of their backpack loads, school conditions, and personal factors that determine backpack loads in Korea. METHOD: We weighed the backpacks of 642 school children in three elementary schools in Suwon city. A validated questionnaire evaluating backpain, features of backpack carrying and subjective perceptions of backpack loads was administered to 450 schoolchildren. The data were divided into two groups, those who had experienced backpain and those who had not. Each group was analyzed according to backpack load, perception of backpack load, school condition and personal factors. RESULTS: The mean weight of the backpack was 2.65 kg, which was 7.85% of mean body weight. The number of children whose backpack loads exceeded 15% of their body weight was 3.3%. 34.5% of children experienced backpain and backpack weight and backpack weight/body weight ratio were significantly higher in the group who experienced backpain. Time spent carrying of backpacks was longer and more students reported heaviness and fatigue when carrying backpacks in the same group. There was a difference in manners of carrying of backpacks and locker usage between the two groups. An improper method of backpack carrying, which is more than 10 cm below the waistline was noted in 85% of the school children. CONCLUSION: Carrying a heavier backpack is related to backpain in schoolchildren and a wide investigation should be performed concerning backpack loads of school children in Korea. Adequate backpack load guidelines should be determined.

A influência de duas mochilas sobre a cinemática da coluna de crianças / The influence of two backpack loads

This study aimed to analyze the effect of backpack load carriage over the spine. The studies that have investigated load carriage using backpacks have analyzed the lower limb dynamics and have not focused on the spine. In addition, the strategies applied by children may differ from adults as the relative weight differs between adolescents and adults. Methods: Ten schoolboys (13.9 ± 0.6 years-old; 1.53 ± 0.05 m; 44.9 ± 3.3 kg) volunteered to participate after their parents sign an informed consent form. Participants walked in a treadmill during approximately 15 minutes carrying a specially built backpack with a load that corresponded to 0.10 and 20 percent BW. A number of landmarks were placed over the subjects back and allowed reconstruction of the spinal profiles in the sagittal and frontal planes. The relation between the segments formed between acromium markers and the posterior superior iliac crest markers was used as a spinal rotation index. The maximum, minimal, mean and range of motion of the thoracic and lumbar regions and the whole spine were analyzed. The gait cycle was applied to normalize the gait cycle. Results indicated differences between the two loads (10 percent) BW and 20 percent BW. A number of changes in the spinal kinematics was found. In the saggital plane the range of movement was unaltered, although there was an increased in the flexion, which was interpreted as a compensatory strategy to counteract the effect of the load. These results are in line with the idea that the use of a backpack increases anterior leaning of the trunk, but are in disagreement with the notion that pronounced changes in the range of motion occur. Carrying a backpack did not produce a clear effect over the variables selected to identify thoracic and lumbar spine regions in the sagittal plane. Conclusion: Carrying a load that corresponded to 20 percent BW influences spinal kinematics in all planes of movements. These changes may impose an important change in posture and stress applied over the posterior aspect of the vertebral column. The slow walking speed used in the present study may have not induced large changes in the kinematics of the vertebral column as in other studies in which walking was performed in greater speeds. Thus, it is suggested that weight of the backpack is not the only factor that determines the movements of the vertebral column.

Este estudo visou analisar o efeito do carregamento de cargas por meio de mochilas sobre a coluna. Os estudos que investigaram o carregamento de cargas utilizando mochilas têm analisado a dinâmica de membros inferiores e não tem focado a coluna vertebral. Em adição, as estratégias aplicadas por crianças podem diferir visto que as cargas relativas podem diferir entre adolescentes e adultos. Métodos: dez escolares (13,9 ± 0,6 anos; 1,53 ± 0,05 m; 44,9 ± 3,3 kg) foram voluntários para participar do estudo após seus pais consentirem e assinarem um formulário livre e esclarecido. Os participantes caminharam em uma esteira. Durante aproximadamente 15 minutos carregando uma mochila especialmente feita que correspondia a 0,10 e 20 por cento do peso corporal. Um número de marcas corporais foi colocada nas costas dos sujeitos que permitiram a reconstrução dos perfis da coluna nos planos sagital e frontal. A relação entre os segmentos formados pelas marcas entre os acrômios e as cristas ilíacas foi usada como um índice de rotação da coluna. Os valores máximos, mínimos, médios e as amplitudes de movimento das regiões torácica e lombar e a coluna toda foram analisados. O ciclo da marcha foi normalizado pelo contato sucessivo de dois contatos do calcanhar com o solo. Resultados indicaram diferenças entre as cargas (10 e 20 por cento) PC). Um número de mudanças na cinemática da coluna foi encontrada. No plano sagital a amplitude de movimento permaneceu inalterada, todavia, houve um aumento na flexão a qual foi interpretada como uma estratégia compensatória em resposta ao efeito da carga. Os resultados estão em linha com a idéia que o uso de mochilas aumenta a inclinação anterior do tronco, mas em discordância com a noção que pronunciadas mudanças na amplitude de movimento ocorrem. O carregamento de cargas não produz um efeito claro sobre as variáveis selecionadas para identificar as alterações nas regiões lombar e torácica no plano sagital. Conclusão: o carregamento de cargas que correspondem a 20 por cento PC influenciam a cinemática da coluna em todos os planos de movimento. Essas mudanças podem impor importantes mudanças sobre a postura e o estresse aplicado sobre os aspectos anteriores e posteriores da coluna vertebral. A baixa velocidade de deslocamento usada no presente estudo podem não ter induzido grandes mudanças na cinematica da coluna vertebral, como demonstrado em outros estudos que usaram maiores velocidades de deslocamento. Desta forma, sugere-se que o peso da mochila não é o único ator que determina os movimentos da coluna vertebral.

Development of model S2000 surgeon backpack and medical corpsman backpack / 医疗卫生装备

This paper introduces the surgeon backpack and medical corpsman backpack which are newly developed for PLA.The twokinds of backpacks being waterproof,water can't penetrate intothem when they are in the rain or floating on water.The basic performance experiments,ergonomics tests and army tryout are performed.The results show that the backpacks are designed reasonably and easy touse.The burthen on the whole backpacks is distributed in the equipment uniformly due toits structure.The physical energy consumption of the person carrying the backpacks decreases due tothe same reason.The medical equipments in the backpacks can accomplish the first aid operations such as binding up,stanching,acesodyne,fastness,ventilation,infection prevention and anti-shock.