The association of backpack use and back pain in adolescents

Effect of Load Carriage Lifestyle on Kinematics and Kinetics of Gait

Backpacks are commonly worn by many people for multiple purposes. This study investigated the effects of habitual wearing of backpacks on lower limb kinematics and kinetics. Fourteen participants were recruited for analysis. All participants performed four randomly assigned scenarios, including running and walking at speeds of 3.5 and 1.5 m/s, respectively, with and without load carriage. The motion analysis system and force plate were used to investigate the lower limb kinematics and kinetics. A paired sample t-test was performed for statistical measurement with a significance level of α = .05. The results indicated that active force, breaking force, impact peak, loading rate, active peak, maximum braking, hip flexion, and hip range of motion were substantially higher under load carriage conditions than under walking condition, however, time to peak was lower. Conversely, during load carriage running, active force, braking impulse, time to peak, ankle plantarflexion, and ankle range of motion were all higher than those during running. Carrying a backpack weighing 10% of the body weight induced different foot strike patterns at both speeds; during load carriage walking, the hip tended to flex more; whereas, during load carriage running, the ankle tended to flex more. In conclusion, human body seems to adopt different gait strategies during load carriage walking and running. That is, the hip strategy is used during walking, while the ankle strategy is used during running.

Prevalence of Musculoskeletal Disorders among General and Technical Secondary School Students in Egypt

(1) Background: Children spend a lot of time within schools. The school setting generally has many ergonomic hazards and reinforced behavior patterns which put children at greater risk of environmental hazards than adults during their critical developmental stages. (2) Objective: The aim of the current study was to investigate the prevalence of musculoskeletal disorders (MSDs) and detect spinal deformities amongst general and technical secondary school students. (3) Methods: A total of 418 students from the second grade of secondary school in Shaquira governorate, Egypt participated in this cross-sectional study. Each student in the study was screened via Nordic Musculoskeletal Questionnaire (NMQ) and had their upper limb posture measured via RULA (Rapid Upper Limb assessment), and the deviation in their thoracic curve was measured using a scoliometer. (4) Results: There was a prevalence of MSDs amongst students as there were 69.7% of general school students and 83.8% of the technical school students suffering from MSDs with a statistically significant difference between both technical and general school students in RULA score and musculoskeletal complaints, whereas there were non-statistical differences in the scoliometer scale in both general and technical education students. (5) Conclusions: Musculoskeletal problems are prevalent among Egyptian secondary school students, with higher prevalence between technical school students. Therefore, preventive measures and strategies are recommended to overcome the future complications of these musculoskeletal disorders.

Prevalence and factors associated with low back pain in schoolchildren in Cameroon, sub-Saharan Africa

BACKGROUND

Data on the prevalence and factors associated with low back pain (LBP) in schoolchildren are scarce in Africa, particularly in sub-Saharan Africa.

OBJECTIVES

To assess the prevalence and factors associated with LBP in schoolchildren in Cameroon.

PATIENTS AND METHODS

We performed a cross-sectional study in 10 randomly selected schools (public and private) in Douala, Cameroon. Using a self-administrated questionnaire, sociodemographic, usual physical activity, and clinical data were collected and all the schoolbags were weighted. Informed consent was obtained from the parents. Statistical significance was established at P < .05. Logistic regression was performed to identify factors associated with LBP.

RESULTS

We included 1075 schoolchildren (543 boys, 50.5%). The prevalence of LBP was 12.3% (132 children: 81 girls and 51 boys). The mean age was 11 ± 1 years (range, 8-14 years). Body mass index was normal in 110 schoolchildren (83.4%). Sixteen schoolchildren had already met a physician for LBP. Among the factors evaluated, those associated with LBP were female gender, doing competitive sport, sitting position, and LBP in at least 1 parent. The mean weight of the schoolbags was 4.9 ± 1.9 kg. We had 99 children with LBP and a schoolbag weight ≥10% of their body weight. No association was found between the weight of schoolbag and LBP.

CONCLUSION

LBP is common in Cameroonian schoolchildren, where 12.3% suffer from it. The weight of schoolbags was not associated with LBP. However, female gender, competitive sport, sitting position, and parental history of LBP were significantly associated with its occurrence.

Effectiveness of a Back School and Postural Education Program on the improvement of literacy about postures and low back pain in adolescents: A 1-year follow-up study

BACKGROUND

Some health problems can be associated with the school environment and lifestyles, so it is necessary to carry out intervention actions that promote health and problem prevention. This study evaluates the effects of a Back School and Postural Education on improving short-term and long-term ergonomic knowledge of postures adopted at school and home, as well as reducing low back pain (LBP) in adolescents.

METHODS

The sample comprises 98 students, aged 10-16 years (11.61 ± 1.28 years), with 63 (64.3%) girls. The measuring instruments included a theoretical and a practical test, a low back pain (LBP) questionnaire and a scale. The tests and the scale have been applied 1 week before the intervention, 1 week following the Back School and Postural Education Program, and a 1 year later. The questionnaire was applied 1 week before of intervention and after 1 year. The intervention included three sessions of a theoretical and practical nature, each lasting 45 min, with intervals of 1 week.

RESULTS

The values of the theoretical test before the intervention, 1 week, and 1 year after the intervention were, respectively, 8.67 ± 2.64, 11.37 ± 1.93, and 11.11 ± 1.92 (p ≤ 0.001), and the practical test were 6.42 ± 2.47, 12.48 ± 2.25, and 12.83 ± 1.78 (p ≤ 0.001). The presence of LBP fell by 42.9%-25.5% after the 1-year period.

CONCLUSIONS

Our data show an improvement of ergonomic knowledge of postures adopted at school and home as a result of the education program and a decrease of self-reported LBP.

Physical and psychological effects of postural educational intervention for students experienced school refusal

Poor posture has been shown to decrease both visceral and respiratory/circulatory function as well as to increase neuro-musculoskeletal system stress. Improper postures of children at school and in daily life can affect their physical and psychological development. In particular, many children who refuse to go to school or who have experienced school refusal have physical and mental problems. Given that posture is closely related to one’s psychological state, modifying one’s posture can improve both physical and psychological health problems. This study examined the changes to school-refusing students’ physical and psychological condition after attending an intervention to improve their posture. The participants were 65 high school students who have experienced school refusal and were attending a program to modify their posture for 2 months. Their posture and psychological states were recorded both pre- and post-intervention with the following measurements: postural alignment and spinal curve according to a sagittal plane, the General Health Questionnaire 30 (GHQ), and the Subjective Adjustment Scale (SAS). Post-intervention, most of the participants saw improvement in their postural alignment (e.g., trunk inclination in standing position, P < 0.001, 95%CI [2.00, 4.00]). Participants with improved standing posture post-intervention had higher SAS scores (e.g., feeling of acceptance and trust, P < 0.05, 95%CI [−3.00, −0.00]). We found that easy-to-implement postural interventions have a positive effect on students’ mental health. Furthermore, it was suggested that their adjustment to school would also improve as their posture improved. The contribution of this study shows that it is possible to care for the physical and mental health of students without using special facilities and techniques. It is hoped that the findings of this study will lead to an improved adjustment to both school or novel environments, as well as prevent health-based school refusal.

Effects of School Backpacks on Spine Biomechanics During Daily Activities: A Narrative Review of Literature

OBJECTIVE

The purpose of this narrative review is to summarize the effects of carrying school backpacks on spine and low-back biomechanics as a risk factor for low back pain in young individuals.

BACKGROUND

Backpacks constitute a considerable daily load for schoolchildren. Consistently, a large number of children attribute their low back pain experience to backpack use.

METHOD

A literature search was conducted using a combination of keywords related to the impact of carrying backpacks on lower back biomechanics. The references of each identified study were further investigated to identify additional studies.

RESULTS

Twenty-two studies met inclusion criteria. A total of 1,159 people aged 7 to 27 years were included in the studies. The added load of a backpack and the changes in spinal posture when carrying a backpack impose considerable demand on internal tissues and likely result in considerable spinal loads. The findings included results related to the effects of backpack weight and position on trunk kinematics and spine posture as well as trunk muscle activity during upright standing, walking, and ascending and descending stairs.

CONCLUSION

Backpack-induced changes in trunk kinematics for a given activity reflect alterations in mechanical demand of the activity on the lower back that should be balanced internally by the active and passive responses of lower back tissues. Although the reported alterations in trunk muscle activities and lumbar posture are indications of changes in the active and passive response of the lower back tissues, the resultant effects on spinal load, that is, an important causal factor for low back pain, remains to be investigated in the future. A knowledge of backpack-induced changes in spinal loads can inform design of interventions aimed at reduction of spinal load via improved backpack design or limitation on carrying duration.

APPLICATION

This narrative review is intended to serve as an educational article for students and trainees in ergonomics and occupational biomechanics.

Effects of Backpacks on Ground Reaction Forces in Children of Different Ages When Walking, Running, and Jumping

Backpacks for transporting school loads are heavily utilized by children, and their mechanical advantages have been allowing children to transport heavy loads. These heavy loads may increase ground reaction forces (GRFs), which can have a negative effect on joints and bone health. The aim of this study was to investigate the effect of backpacks on the GRFs generated by children during walking, running, and jumping. Twenty-one children from the fifth (G-5, n = 9) and ninth (G-9, n = 12) grades walked, ran, and jumped over a force plate. When walking, the G-5 had GRF increments in the first (17.3%; p < 0.001) and second (15.4%; p < 0.001) peak magnitude, and in the total integral of the vertical force (20%; p < 0.001), compared to the control condition (i.e., no backpack), and the G-9 had increments of 10.4%, 9%, and 9% (p < 0.001), respectively. The G-9 did not prolong their total stance time (p > 0.05), unlike the G-5 (p = 0.001). When running, total stance time increased 15% (p < 0.001) and 8.5% (p < 0.001) proportionally to the relative load carried, in the G-5 and G-9, respectively. Peak GRF did not increase in any group when running or landing from a jump over an obstacle. It was found that GRF was affected by the backpack load when walking and running. However, when landing from a jump with the backpack, schoolchildren smoothed the landing by prolonging the reception time and thus avoiding GRF peak magnitudes.

Potential risk factors and triggers for back pain in children and young adults. A scoping review, part II: unclear or mixed types of back pain

Background

Back pain is a global problem in terms of disability and financially, with a large burden both to the individual and to society. Back pain was previously believed to be uncommon in children. However, there is a growing body of evidence that this is not the case.

Objective

Part I of this scoping review studied risk factors of incident and episodic back pain. In this part II we aimed to identify all risk factors and triggers with unclear or mixed type back pain in young people and to identify any gaps in the literature.

Methods

A scoping review design was selected to summarise the evidence, as there are many studies on “risk factors” for back pain. The scoping review followed the PRISMSA-ScR guidelines. We considered all studies that tested potential risk factors and triggers for thoracic and/or lumbar spine pain, in children, adolescents, and young adults (≤ 24 years). PubMed and Cochrane databases were searched from inception to September 2018, to identify relevant English language articles. The results regarding potential risk factors were separated into temporal precursors and bidirectional risk factors and the studies were classified by study design.

Results

Our comprehensive search strategy identified 7356 articles, of which 83 articles were considered eligible for this review (part II). There were 53 cross-sectional studies and 30 cohort studies. Potential risk factors for back pain were: female sex, older age, later pubertal status, positive family history of back pain, increased growth, and a history of back pain, most of which are temporal precursor variables. There was limited research for the illness factors, spinal posture, and muscle endurance in the development of back pain.

Conclusion

Many of the included studies approached risk factors in similar ways and found factors that were associated with back pain but were not obvious risk factors as causality was uncertain. Future research should be more rigorous and innovative in the way that risk factors are considered. This could be through statistical approaches including cumulative exposures, or longitudinal approaches including multi-trajectory methods. Additionally, data on proposed risk factors should be collected before the onset of back pain.

Effects of carrying school bags on cervical and shoulder posture in static and dynamic conditions in adolescent students

Background Neck and Back Pain in Students is closely related to the school bags that they carry. There is a dearth of literature in terms of postural changes due to school bags in adolescents, especially those discussing postural changes in static and dynamic loading conditions. Objective To assess the effects of weight, position, and time of school bag carriage in static and dynamic conditions on cervical and shoulder posture in adolescent students. Subjects Seventy adolescents (35 Females, 35 Males) between 10 and 15 years of age. Methods: Craniohorizontal Angle, Craniovertebral Angle, Sagittal Shoulder Posture, Anterior Head Alignment were assessed in 7 different conditions using Photographic Method and MB Ruler. Results and Conclusion Significant changes in Sagittal Shoulder Posture and Craniohorizontal Angle were found with unilateral school bag carriage as compared to minimal significant postural changes with bilateral carriage. Maximal significant postural changes, in terms of all outcome measures were noted during loaded dynamic activity. Craniovertebral Angle kept significantly reducing with time. Immediate assessments taken with a school bag weighing 13.5% of the body weight showed a significant decrement in the Craniohorizontal Angle. Even a bag weighing less than 10% of the body weight proved to bring about biomechanical changes, when assessments were taken during the activities that a child has to perform with a school bag (Post Standing, Post Walking, and During Walking).

Back pain and school bag weight - a study on Indian children and review of literature

Back pain in children is a complex phenomenon, which has been shown to be associated with physical and psychosocial factors. None of the studies on Indian children have investigated the possible association between back pain and psychosocial factors. We decided to determine the prevalence of back pain in students and association with both physical and psychosocial factors. A cross-sectional study was conducted on 163 students from two city schools. Physical factors were evaluated using a structured questionnaire. Strengths and difficulties questionnaire was used to assess psychosocial factors. The studied sample consisted of 49.7% boys and 50.3% girls. Mean school bag weight was 6.1±2.4 kg (range: 2.2-15.6 kg). Mean weight of school bag as a percentage of body weight was 13.5±6.2%. Approximately 76% students carried more than 10% of their body weight. The prevalence of back pain (over last 1 month) was 53.9%. No associations were found between back pain and weight of school bag, weight of school bag as a percentage of body weight and physical activities. Significant associations were found between back pain and number of hours spent watching television [odds ratio (OR): 3.3, 95% confidence interval (CI): 1.5-7.5; P=0.003], history of injury to the back (OR: 4.8, 95% CI: 1.47-15.8, P=0.003), presence of a family member complaining of back pain (OR: 1.98, 95% CI: 1.25-3.14, P=0.002), conduct (P=0.042) and hyperactivity problems (P=0.045). Thus, there appears a need to consider psychosocial factors along with physical factors when evaluating a young student with back pain.

Prevalence of back pain and the knowledge of preventive measures in a cohort of 11619 Polish school-age children and youth-an epidemiological study

The study sought to characterize back pain (BP) (in the period of 12 months) in children and youth aged 10 to 19 from eastern Poland.The study included 11619 children and youth (6254 girls and 5365 boys) aged 10 to 19 from eastern Poland. An original questionnaire was applied as a research tool. Before the study, the reliability of the questionnaire had been assessed. The Kappa coefficient value for all the analyzed variables was equal to or higher than 0.91.Over 74.4% of the respondents admitted that within the last 12 months, they had experienced BP which was usually located in the lumbar spine (55.8%). The percentage of individuals reporting BP increased with age of participants. Girls reported BP more often than boys (82.8% vs 64.3%). The main circumstances in which BP occurred included lifting heavy objects, carrying school backpack and maintaining a sedentary position (70.7% vs 67.4% vs 67.8%). Over 67% of the respondents declared they did not know ergonomic principles.High prevalence of BP was noted. The declared BP was mainly located in the lumbar spine. Girls reported BP more often than boys. The students presented a very low level of knowledge about ergonomics. Therefore, the appropriate education should be included at school.

The Impact of Backpack Loads on School Children: A Critical Narrative Review

Background: Backpack loads of school students during school days have been suggested to range from 10% to as high as 25% of their body weight and may have a negative impact on their body. The aim of this review was to identify and review studies that have examined impacts of contemporary backpack loads on school children. Methods: A systematic search was conducted of the literature using key search terms. After relevant studies published in recent years were selected using strict inclusion and exclusion criteria, the studies were critically appraised and relevant data were extracted and tabulated prior to conducting a critical narrative synthesis of findings. Results: Twenty-one studies were included, ranging in methodological quality from poor to good (critical appraisal scores 22% to 77%). Students carried on average over 15% of their own body weight, which caused biomechanical and physiological adaptations that could increase musculoskeletal injury risk, fatigue, redness, swelling and discomfort. Conclusion: Considering the limited methodological quality and variations in foci across studies, further research is needed to elucidate: (1) the loads students carry around on a school day in their school backpacks and; (2) the biomechanical, physiological and physical effects of load carriage on students.

The effects of backpack type on lumbo-pelvic coordination during trunk bending and return tasks

Backpacks with ergonomic features are recommended to mitigate the risk of developing low back pain due to carrying a heavy school backpack. A repeated measure study was conducted on 40 college-age students to investigate the immediate changes in magnitude and timing aspects of lumbo-pelvic coordination when carrying an ergonomically modified vs. a normal backpack relative to no backpack condition during trunk forward bending and backward return tasks. We found a smaller reduction in the thoracic range of rotation, an increase vs. a decrease in pelvic range of rotation and a larger reduction in lumbar flexion for a modified vs. a normal backpack. Furthermore, during the forward bending, a less in-phase motion for the modified backpack was observed. Our results suggest that participants have likely experienced larger spinal loads with the modified backpack; a conclusion that should be investigated in future to determine whether ergonomic backpacks can reduce the risk of low back pain in children. Practitioner summary: Research participants performed trunk bending and return closer to their habitual way under modified versus normal school backpack. From an equilibrium point of view, therefore, individuals are likely experiencing larger spinal loads during activities of daily living with a modified backpack. However, such a conclusion may change when considering stability requirements.

Effects of an improved biomechanical backpack strap design on load transfer to the shoulder soft tissues

The aim of the present study was to characterize shoulder strap structure and mechanical properties that may alleviate strains and stresses in the soft tissues of the shoulder. Utilizing a finite element model of the shoulder constructed from a single subject, we have quantified skin stresses exerted by backpack straps and the strains at the subclavian artery (SCA). For this end, standard shape straps with stiffness of 0.5, 1.2, and 5 MPa, were compared to the effects of optimized straps; a double-layered (soft outer layer and reinforced internal supporting layer) and newly-designed anatomically-shaped strap. Compared to the standard 0.5 MPa strap, the 5 MPa strap resulted in 4-times lower SCA strains and 2-times lower Trapezius stresses. The double-layered strap resulted in 40% and 50% reduction in SCA strains and skin stresses, respectively, with respect to the softer strap. The newly-designed anatomical strap exerted 4-times lower SCA strains and 50% lower skin stresses compared to the standard strap. This demonstrates a substantial improvement to the load carriage ergonomics when using a composite anatomical strap.

The Influence of Backpack Weight and Hip Belt Tension on Movement and Loading in the Pelvis and Lower Limbs during Walking

The introduction of hip belts to backpacks has caused a shift of loading from the spine to the hips with reported improvements in musculoskeletal comfort. Yet the effects of different hip belt tensions on gait biomechanics remain largely unknown. The goal of this study was to assess the influence of backpack weight and hip belt tension on gait biomechanics. Data from optical motion capture and ground reaction forces (GRF) during walking were acquired in nine healthy male subjects (age 28.0 ± 3.9 years). Six configurations of a commercial backpack were analyzed, that is, 15 kg, 20 kg, and 25 kg loading with 30 N and 120 N hip belt tension. Joint ranges of motion (ROM), peak GRF, and joint moments during gait were analyzed for significant differences by repeated measures of ANOVA with Bonferroni post hoc comparison. Increased loading led to a significant reduction of knee flexion-extension ROM as well as pelvis rotational ROM. No statistically significant effect of hip belt tension magnitudes on gait dynamics was found at any backpack weight, yet there was a trend of increased pelvis ROM in the transverse plane with higher hip belt tension at 25 kg loading. Further research is needed to elucidate the optimum hip belt tension magnitudes for different loading weights to reduce the risks of injury especially with higher loading.

Effects of backpack load and positioning on nonlinear gait features in young adults

Overloaded backpacks can cause changes in posture and gait dynamic balance. Therefore, the aim of this study was to assess gait regularity and local dynamic stability in young adults as they carried a backpack in different positions, and with different loads. Twenty-one healthy young adults participated in the study, carrying a backpack that was loaded with 10 and 20% of their body weight (BW). The participants walked on a level treadmill at their preferred walking speeds for 4 min under different conditions of backpack load and position (i.e. with backpack positioned back bilaterally, back unilaterally, frontally or without a backpack). Results indicate that backpack load and positioning significantly influence gait stability and regularity, with the exception of the 10% BW bilateral back position. Therefore, the recommended safe load for school-age children and adolescents (10% of BW) should also be considered for young adults. Practitioner summary: Increase in load results in changes in posture, muscle activity and gait parameters, so we investigated the gait adaptations related to regularity and stability. Conditions with high backpack loads significantly influenced gait stability and regularity in a position-dependent manner, except for 10% body weight bilateral back position.

Low Back Pain in Adolescents: A 1-Year Analysis of Eventual Diagnoses

BACKGROUND

Back pain in adolescents is very common and often seen in the office for evaluation of potential spinal pathology. Pediatric back pain has often thought to be from serious identifiable causes such as spondylolysis, spondylolisthesis, tumor, or infection. A follow-up analysis of adolescents initially presenting with back pain to their eventual subsequent diagnosis within 1 year has not been reported on a large scale with a national sample.

METHODS

A national insurance database (PearlDiver Patient Records Database) was queried for ICD-9 codes to identify patients aged 10 to 19 years with back pain from 2007 to 2010. These patients were tracked for imaging obtained, and eventual development of subsequent associated spinal pathology diagnoses using CPT and ICD-9 codes for up to 1 year after initial presentation.

RESULTS

A total of 215,592 adolescents were identified presenting with low back pain (LBP) from 2007 to 2010. Over 80% of adolescents with LBP had no identifiable diagnosis within 1 year. The most common associated subsequent diagnoses were lumbar strain/spasm (8.9%), followed by scoliosis (4.7%), lumbar degenerative disk disease (1.7%), and lumbar disk herniation (1.3%). The rates of all other diagnoses including spondylolysis, spondylolisthesis, infection, tumor, and fracture had <1% association with LBP.

CONCLUSIONS

In conclusion, adolescent LBP is a common diagnosis for which underlying serious pathology is rare. The most common diagnosis aside from strain or muscle spasm associated with LBP are scoliosis and degenerative disk disease. Pediatric orthopaedists often are consulted on patients with LBP and should always have high suspicion for potential serious spinal pathology, but should recognize the most common etiologies of back pain in adolescence.

LEVEL OF EVIDENCE

Level IV-case series.

Parental awareness of schoolbag carriage: A comparative study of Irish and United States parents

BACKGROUND

Given the global nature of schoolbag carriage, there has been extensive research on schoolbag weight and use with resultant guidance on many aspects of carrying a schoolbag. However, there is limited evidence of knowledge translation or parents' awareness of schoolbag carriage.

OBJECTIVE

This study investigated parental awareness of factors related to schoolbag carriage.

METHOD

A cross-sectional survey using an anonymous 30-item questionnaire and purposive sampling was used. Questionnaires were distributed to parents of primary school children through the schools. Descriptive statistics of frequencies and percentages were used and associations were tested using Chi-square analysis in SPSS v23.

RESULTS

A total of 700 parents in Ireland (Ire) and the United States (US) participated in the study (n = 444 [Ire] and n = 256 [US]). Generally, parents had satisfactory awareness of appropriate schoolbag type and carriage. The majority of children owned a backpack (89.9% [Ire] vs. 93.7% [US]), although fewer parents considered this to be the most suitable bag for their child (69.6% [Ire] vs. 88.2% [US]). More Irish parents (29.2%) favoured a wheeled schoolbag compared to US parents (6.2%) (p < 0.001). The majority (70.8% [Ire] vs. 55.7% [US]) wanted more information. The preferred platforms for receiving information were a handout (78.1% [Ire] vs. 71.6% [US]) and on-line (44.6% [Ire] vs. 53.9% [US]).

CONCLUSIONS

Despite gaps identified, parents had good awareness of factors relating to schoolbag carriage, but this study shows that they would like more information. The preferred platform for knowledge translation was a handout. Parents are the best advocates for safety promotion and represent the group most likely to improve schoolbag carriage among children.

Validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage

Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R²>0.5) in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt, were assessed. The mechanical parameters were measured in the shoulder and the hip region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg), combined with four different hip belt tensions (30N, 60N, 90N, and 120N). Through the significant (p<0.05) correlation of the mechanical parameters measured on the dummy with the corresponding values of the subject study, the dummy was validated for all static measurements and for dynamic measurements in the hip region to accurately simulate the interaction between the human body and the load carriage system. Multiple linear regressions with the mechanical parameters measured on the dummy as independent variables and the corresponding subjective discomfort scores from the subject study as the dependent variable revealed a high predictive power of the instrumented dummy. The dummy can explain 75% or more of the variance in discomfort using average pressures as predictors and even 79% or more of the variance in discomfort using strap forces as predictors. Use of the dummy enables objective, fast, and iterative assessments of load carriage systems and therefore reduces the need for labor-intensive subject studies in order to decrease the mechanical aspects of discomfort during load carriage.

Postural habits and weight of backpacks of Portuguese adolescents: Are they associated with scoliosis and low back pain?

BACKGROUND

The adoption of incorrect postures or carrying overweight backpacks may contribute to the development of musculoskeletal disorders in school children.

OBJECTIVE

This study evaluated the weight of backpacks and the postural habits adopted in schools by Portuguese adolescents, and their association with scoliosis and low back pain (LBP).

METHOD

The sample comprised 966 Portuguese students, aged between 10 and 16 years. The instruments included a questionnaire to characterize the presence of LBP and the postural habits adopted by students, the weighing of backpacks and a scoliometer to evaluate scoliosis.

RESULTS

No association was observed between assuming incorrect postures and carrying overweight backpacks, in students with scoliosis. Students who adopted incorrect sitting postures had 1.77 times the risk (95% CI: 1.32-2.36; p < 0.001) of developing LBP; those positioned incorrectly whilst watching TV and playing games had 1.44 times the risk (95% CI: 1.08-1.90; p = 0.012) of developing LBP; and those standing incorrectly had 2.39 the risk (95% CI: 1.52-3.78; p < 0.001) of developing LBP.

CONCLUSIONS

The results revealed that students who sat with the spine positioned wrongly, as well as those who were standing incorrectly, were more likely to present with LBP.

Effect of variable backpack load and strap option on the pulmonary function of children: A simulation using treadmill walking

BACKGROUND

The restrictive effect of backpack loads on chest expansion has been widely reported but little is known whether pulmonary function in children is affected by the placement of the straps of the backpack.

OBJECTIVE

To determine the effects of strap configuration and backpack loads on pulmonary function among school age children.

METHODS

Eighteen children (mean age of 12±1.68 years) participated in this study. Pulmonary functionwas assessed using spirometryat baseline and during five test conditions. Two strap configurations were compared: double straps with the backpack worn midline on the back with one strap over each shoulder and single strap with the backpack worn laterally with one strap over the shoulder.

RESULTS

A marginal increase was shown in all measures of pulmonary function during standing and walking, and as the backpack weight increased. However, all the marginal changes in pulmonary function tests across different weights and strap patterns were not statistically significant.

CONCLUSION

Variable backpack loading and strap options appear to influence changes to the pulmonary function of children. Although the observed changes are marginal, it could not be determined if they have a long term effect. Further investigations of larger sample size are required to inform practice.

Effect of Backpack Strap Patterns on Gait Parameters in Young Adults at Self-Selected Normal and Fast Walking Speeds

BACKGROUND

The effects of backpack load on young adults' gait parameters have received little attention. We previously reported that with a backpack load within 15% body weight (BW), young adults maintain their gait parameters at the expense of increased exertion during a 6-minute walk at self-selected normal walking speed. However, the effect of backpack strap pattern on gait parameters during faster walking or longer stride length has not been evaluated.

OBJECTIVE

To determine the effect of different backpack strap patterns on gait parameters during a 12-minute walk test in young adults at self-selected normal and fast walking speeds.

DESIGN

A crossover, self-controlled experimental study with repeated measures.

SETTING

Department of Medical Rehabilitation, University of Nigeria.

PARTICIPANTS

A convenience sample of 24 healthy young adults (21.29 ± 1.20 years) who voluntarily signed an informed consent form, were able to wear a backpack on 1 and on both shoulders, were able to walk independently, and passed the physical activity readiness screening participated in this study.

METHODS

Using a validated method of an observational gait analysis, each participant carried out a 12-minute walk test at self-determined normal and fast walking speeds, respectively. The effect of the following test conditions on the selected gait parameters was evaluated: normal and fast walking without load, and normal and fast walking with 10% and 20% BW backpack carried each on 1 and both shoulders.

MAIN OUTCOME MEASUREMENT

Stride length, stride time, velocity, cadence, and base of support were assessed by the equation definitions method of the velocity field diagram.

RESULTS

At self-selected fast walking speed with 10% BW backpack load, stride time (P = .004) and cadence (P = .006) were significantly decreased when participants wore a double-strap backpack. At self-selected normal walking speed with 20% BW backpack load, cadence was significantly decreased with double-strap backpack carriage (P = .008). Cadence (P < .001), velocity (P < .001), and stride time (P < .001)were also significantly decreased at both conditions of single and double-strap backpack carriage of 20% BW respectively at fast walking speed.

CONCLUSION

Backpack strap patterns do not affect the gait parameters of young adults in a 12-minute bout of normal walking speed, provided that the load is less than 20% BW. However, a load up to 10% BW carried on a double strap causes a decrease in stride time and cadence when these individuals walk fast.

LEVEL OF EVIDENCE

Not applicable.

The relationship between back pain and schoolbag use: a cross-sectional study of 5,318 Italian students

BACKGROUND CONTEXT

Back pain at a young age is considered to be predictive of chronicity. Several studies have investigated the relationship between the use of a schoolbag and back pain, although some aspects are still unclear.

PURPOSE

The aim of this study was to evaluate back pain due to schoolbag use in terms of (1) prevalence and intensity, (2) differences between male and female pupils, and (3) predisposing factors.

STUDY DESIGN

This is a cross-sectional study.

PATIENT SAMPLE

The sample was composed of 5,318 healthy pupils aged 6 to 19 years (classified according to three age groups: children, younger adolescents, and older adolescents).

OUTCOME MEASURES

Schoolbag-related pain was assessed by means of an ad hoc questionnaire. The intensity of pain was assessed using the Wong scale.

METHODS

Subjects underwent a face-to-face interview using an ad hoc questionnaire. The intensity of pain was assessed using the Wong scale. On the basis of the prevalence and intensity of back pain, we divided our population into two groups: (1) no or mild pain group and (2) moderate or severe pain group. The "schoolbag load" (ratio between schoolbag and pupil weight multiplied by 100) was calculated for each subject.

RESULTS

More than 60% of the subjects reported pain. Although the schoolbag load decreased from children to young and older adolescents, schoolbag-related pain significantly increased (p<.001). Girls reported significantly more frequent and more severe pain than boys. The logistic model confirmed that adolescent girls are the group at greatest risk of suffering from intense pain. The schoolbag load had a weak impact on back pain, whereas the schoolbag carrying time was a strong predictor.

CONCLUSIONS

Adolescent girls have the highest risk of experiencing severe back pain, regardless of schoolbag load. This suggests that other factors (anatomical, physiological, or environmental) might play an important role in pain perception. These aspects should be investigated to plan appropriate preventive and rehabilitative strategies.

Use of a backpack alters gait initiation of high school students

We assessed how backpack carriage influences the gait initiation (GI) process in high school students, who extensively use backpacks. GI involves different dynamics from gait itself, while the excessive use of backpacks can result in adverse effects. 117 high school students were evaluated in three experimental conditions: no backpack (NB), bilateral backpack (BB), and unilateral backpack (UB). Two force plates were used to acquire ground reaction forces (GRFs) and moments for each foot separately. Center of pressure (COP) scalar variables were extracted, and statistical parametric mapping analysis was performed over the entire COP/GRFs time series. GI anticipatory postural adjustments (APAs) were reduced and were faster in backpack conditions; medial-lateral COP excursion was smaller in this phase. The uneven distribution of the extra load in the UB condition led to a larger medial-lateral COP shift in the support-foot unloading phase, with a corresponding vertical GRF change that suggests a more pronounced unloading swing foot/loading support foot mechanism. The anterior-posterior GRFs were altered, but the COP was not. A possible explanation for these results may be the forward trunk lean and the center of mass proximity of the base of support boundary, which induced smaller and faster APA, increased swing foot/support foot weight transfer, and increased load transfer to the first step.

Differences in personal and lifestyle characteristics among Zimbabwean high school adolescents with and without recurrent non-specific low back pain: a two part cross-sectional study

BACKGROUND

Recurrent non-specific low back pain (NSLBP) is increasingly becoming common among adolescents worldwide. A recent study in Zimbabwe showed a relatively high prevalence (28.8 %) among high school students. Influential associated factors, however, remain unclear. This is a significant shortcoming. The aim was to determine personal or lifestyle-related factors associated with recurrent NSLBP among high school adolescents in Harare, Zimbabwe.

METHODS

This study was part of a large epidemiological study conducted in two continuous parts. Part one sought to determine self-reported associated factors among 532 participants (mean age =16 ± 1.72 years) drawn randomly from selected government schools using a reliable and content-validated questionnaire (Kappa coefficient, k = 0.32-1). Part two purposively identified adolescents (N = 64, median age =17 years, interquartile range, IQR = 15-18 years) with a history of 'severe' recurrent NSLBP from part one based on a specific eligibility criteria and compared body mass index, relative school bag weight and hamstring flexibility with matched adolescents without NSLBP. Data was analysed using Statistica version 11. Independent t-tests or χ2 tests of association were used for continuous and categorical data, respectively. The statistical significance was set at p < .05.

RESULTS

Recurrent NSLBP was associated with self-reported factors such as perceptions of a heavy school bag [χ2 (1) = 85.9, p < 0.001]. A significant proportion of adolescents with recurrent NSLBP spent over 30 min carrying the school bag to and from school [χ2 (1) =32.2, p < 0.001]. It was also associated with prolonged sitting (p < 0.001), not playing sports [χ2 (1) =5.85, p = 0.02] and tight hamstrings [χ2 (1) =7.6, p = 0.006].

CONCLUSIONS

Although conclusions from this study are hesitant because of the cross-sectional nature of the study and the relatively small sample size in follow-up study, recurrent NSLBP is associated with perceptions of a heavy school bag, duration of school bag carriage, no sports participation, prolonged sitting on entertainment activities, and tight hamstrings. These findings add to the importance of promoting physical activity at school or home especially aimed at improving muscle flexibility.

Mechanical Predictors of Discomfort during Load Carriage

Discomfort during load carriage is a major issue for activities using backpacks (e.g. infantry maneuvers, children carrying school supplies, or outdoor sports). It is currently unclear which mechanical parameters are responsible for subjectively perceived discomfort. The aim of this study was to identify objectively measured mechanical predictors of discomfort during load carriage. We compared twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt. The pressure distribution under the hip belt and the shoulder strap, as well as the tensile force in the strap and the relative motion of the backpack were measured. Multiple linear regression analyses were conducted to investigate possible predictors of discomfort. The results demonstrate that static peak pressure, or alternatively, static strap force is a significant (p<0.001) predictor of discomfort during load carriage in the shoulder and hip region, accounting for 85% or more of the variation in discomfort. As an additional finding, we discovered that the regression coefficients of these predictors are significantly smaller for the hip than for the shoulder region. As static peak pressure is measured directly on the body, it is less dependent on the type of load carriage system than static strap force. Therefore, static peak pressure is well suited as a generally applicable, objective mechanical parameter for the optimization of load carriage system design. Alternatively, when limited to load carriage systems of the type backpack with hip belt, static strap force is the most valuable predictor of discomfort. The regionally differing regression coefficients of both predictors imply that the hip region is significantly more tolerant than the shoulder region. In order to minimize discomfort, users should be encouraged to shift load from the shoulders to the hip region wherever possible, at the same time likely decreasing the risk of low back pain or injury.

Effects of carrying a backpack in an asymmetrical manner on the asymmetries of the trunk and parameters defining lateral flexion of the spine

OBJECTIVE

The aim of this study was to examine changes in the body posture parameters defining asymmetry of the trunk and lateral flexion of the spine in children while carrying a backpack weighing 10% of a child's weight.

BACKGROUND

Carrying a backpack may negatively affect the posture of schoolchildren and contribute to spinal pain.

METHOD

The study involved 162 primary school students ages 11 to 13 years. The parameters describing body posture were assessed with a backpack carried on the right or left shoulder as well as without a load. To assess the predefined parameters, we used the CQ Elektronik System, employing the photogrammetric method.

RESULTS

Trunk inclination shifted significantly in the opposite direction to the shoulder the backpack was carried on, and an increase in shoulder asymmetry was also found. We also observed a more pronounced right-side lateral flexion of the spine when the backpack was carried on the right shoulder and an analogous relationship for the left side.

CONCLUSION

The results of this study show that carrying a backpack in an asymmetrical manner negatively affects spine, even if the backpack weight constitutes 10% of the child's weight, which has been previously recommended as a safe load for a child's shoulders.

APPLICATION

We suggest that the issue of safe backpack weight be reassessed and that students be taught basic ergonomic principles on how to carry loads. Changes to the management pattern of carrying textbooks to and from school also should be considered.

Non-specific low back pain in adolescents from the south of Portugal: prevalence and associated factors

BACKGROUND

Low back pain (LBP) is a common condition in children and adolescents, and the prevalence has been increasing over the years. Most cases of LBP are due to non-specific causes; however, the role of these risk factors is still controversial. This study determined the prevalence of LBP in Portuguese adolescents and characterized the associated factors.

METHODS

The design of this study was observational, analytical and cross-sectional. The sample included 966 adolescents from southern Portugal, aged between 10 and 16 years. The assessments included a questionnaire to characterize the presence of LBP, postural habits, body mass index (BMI) and backpack weights and to use a scoliometer to evaluate the presence of scoliosis.

RESULTS

One hundred fifty-two (15.7 %) students had LPB at the present time, 456 (47.2 %) had experienced it in the last year, and 600 (62.1 %) had lifetime prevalence of LBP. Girls have 2.05 more probability of presenting LBP than boys (95 % CI 1.58-2.65; p < 0.001), and older students have a 1.54 greater probability (95 % CI 1.19-1.99; p = 0.001). Students who sit with the spine incorrectly positioned presented 2.49 greater probability of having LBP (95 % CI 1.91-3.2; p < 0.001), students using improper positions for watching TV or playing games have 2.01 greater probabilities (95 % CI 1.55-2.61; p < 0.001), and those who adopt an incorrect standing posture have a 3.39 greater chance of experiencing LBP (95 % CI 2.19-5.23; p < 0.001).

CONCLUSIONS

This study found a high prevalence of LBP in adolescents, with higher values in older students, female students and those who adopted incorrect positions when sitting or standing.

Neck, shoulder and low back pain in secondary schoolchildren in relation to schoolbag carriage: should the recommended weight limits be gender-specific?

The occurrence of neck, shoulder and low back complaints in relation to schoolbag carriage and other potential risk factors were investigated in a cross-sectional study of 586 Iranian schoolchildren aged 12-14 years. The average load carried by schoolchildren was 2.8 kg. Neck, shoulder and low back complaints during the preceding month were reported by 35.3%, 26.1% and 33% of the students, respectively. Gender was an independent factor predicting musculoskeletal symptoms in schoolchildren. Girls were more likely than boys to suffer from neck, shoulder and low back complaints, although there was no significant difference between genders in terms of schoolbag carriage variables. The findings suggest that the recommended weight limit for schoolbag carriage may need to differ between boys and girls. The associations between schoolbag variables and reported symptoms are also discussed. The results provide evidence that the current weight limit should consider a broader combination of factors that influence the use of schoolbags.

Altered disc compression in children with idiopathic low back pain: an upright magnetic resonance imaging backpack study

STUDY DESIGN

This study is a repeated measures design to measure the lumbar spine's response to common backpack loads in children with idiopathic low back pain (ILBP) using upright magnetic resonance imaging (MRI).

OBJECTIVE

The purpose of this study is to analyze the lumbar spine's response to backpack loads with upright MRI in children with ILBP to compare their results with previously published normal child data under the same conditions. We hypothesize that typical backpack loads will have a different effect on the lumbar spine of normal children and children with ILBP.

SUMMARY OF BACKGROUND DATA

Research in normal children shows that backpack loads compress the lumbar intervertebral discs (IVDs), increase lumbar coronal deformity, and increase pain.

METHODS

Fifteen pediatric and adolescent patients with ILBP were selected. Patients were excluded if a spinal deformity, an underlying pathology, or known injury was identified. A 0.6-T upright MRI scanner imaged the subjects while in supine and standing positions wearing 0-kg, 4-kg, and 8-kg backpacks. IVD height, lumbar lordosis, lumbar coronal deformity, and pain score were recorded after each condition and compared using analysis of variances. We compared the above-mentioned variables between ILBP and normal subjects using generalized least squares models.

RESULTS

The cohort's mean age was 13 ± 3 years. The 4-kg and 8-kg backpacks only compressed the L5-S1 IVD relative to upright with no load. Subjects experienced increasing pain with increasing load. Load had no effect on lumbar lordosis or lumbar coronal deformity. Compared with normal children, children with ILBP experience significantly less disc compression at T12-L1 to L4-L5, less lumbar lordosis, and more pain with increasing load.

CONCLUSION

In children with ILBP, increasing backpack load compresses only the L5-S1 IVD. Compared with normal children, children with ILBP experience less lumbar IVD compression, less lumbar lordosis, and more pain due to increasing load suggesting altered mechanisms for load tolerance in children with ILBP.

LEVEL OF EVIDENCE

3.

Primary prevention of disc degeneration-related symptoms

INTRODUCTION

It has been shown previously that a history of low back pain often begins in childhood or adulthood. Indeed, the prevalence of severe back symptoms among schoolchildren is not insignificant. Possibilities for the primary prevention of intervertebral disc degeneration-related conditions are poorly reported in the literature despite the assumed socio-economical impact of the prevention of these conditions.

METHODS

In this review, the authors have collated published data on the prevalence and risk factors of childhood low back pain as well as the structure and results of published primary prevention programs.

RESULTS

The prevalence of self-reported low back pain is 7-65% among children and it increases with age. Several lifestyle factors have been reported as significant risk factors for back pain, many of which are related to the schools. Current educational primary prevention programs in schools show no clear or long-term stable effect.

CONCLUSION

Considering the growing evidence about the importance of normal and bad posture, an exercise-based posture correction program is suggested as a school-based primary prevention of disc degeneration-related symptoms. Further, prospective randomized studies with more than 20 years follow-up, however, are strongly required to confirm it.

Association of Parental Awareness of Using Schoolbags With Musculoskeletal Symptoms and Carrying Habits of Schoolchildren

The association between parental awareness of using schoolbags and the occurrence of musculoskeletal symptoms and carrying habits of children was investigated in a cross-sectional study in Tabriz, Iran. Data on 454 students aged 11−14 years and their parents ( n = 358) were analyzed. The awareness of the recommended weight limit, appropriate method of carrying schoolbags, and schoolbag strap adjustments was generally low among the respondents. A higher parental awareness of the schoolbag weight was associated with a lower prevalence of upper back and shoulder complaints among children and carrying loads less than 10% of their body weight. The findings suggest that parental awareness should have a more prominent role in changing the schoolbag carrying habits of children and particularly in reducing the weight of loads carried by them. This highlights the need to incorporate guidelines and recommendations into practice to ensure that the health and safety of schoolchildren are not compromised when using schoolbags.

Effects of carrying a backpack in a symmetrical manner on the shape of the feet

The aim of this study was to assess changes in the shape of the feet while carrying a backpack constituting 10% of a child's weight. It was an observational, cross-sectional study involving 118 primary school children aged 11-13 years. Selected parameters of foot shape were assessed in both a normal position and with a backpack using podoscopy and a CQ-ST examination device. The study revealed significant differences in the length and width of the right and left feet between assessments. Moreover, the longitudinal arch of the foot was significantly lowered and deformity of the great toe was reported. Carrying a backpack constituting 10% of a child's weight results in lowering of the longitudinal and traverse arches of the feet and advanced toe deformities.

PRACTITIONER SUMMARY

We performed an observational, cross-sectional study examining the effect of carrying a backpack constituting 10% of a child's weight on parameters of foot shape and observed significant lowering of the longitudinal and traverse arches of the feet and advanced toe deformities.

Epidemiology of back pain in children and youth aged 10-19 from the area of the southeast of Poland

OBJECTIVE

The aim of this work was to define the prevalence of back pain in children and youth aged 10-19 from the southeast of Poland.

MATERIAL AND METHODS

The cross-sectional study included 1089 students (547 girls and 542 boys) aged 10-19. The prevalence of back pain, its intensity, location, and situations in which it occurred were assessed with a questionnaire.

RESULTS

Among 1089 respondents, 830 (76.2%) admitted that they had experienced back pain at various frequencies within the year preceding the study. Back pain was located mainly in the lumbar segment (74.8%). Mild pains were dominant, which was declared by 44.7% of the respondents. Girls experienced back pain significantly more frequently than boys (52.2% versus 47.8%, P < 0.05).

CONCLUSIONS

The research revealed that back pain is a common phenomenon. The prevalence of back pain in children and youth living in southeast Poland is similar to the frequency of occurrence of such complaints occurring in peers in other countries. It seems significant to monitor the remaining regions of Poland in order to define the scale of the problem and to look for the risk factors of back pain in children and youth to undertake efficient prophylactic actions.

Schoolbag weight limit: can it be defined?

BACKGROUND

Carrying a schoolbag is a daily activity for most children and much research has been conducted in an effort to identify a safe load limit for children to carry in their schoolbags. Despite this, there is still no consensus about guideline weight and other factors associated with carrying a schoolbag. The objective of this article is to review the literature on schoolbags with particular emphasis on the load limit guidelines and schoolbag-related musculoskeletal pain, and to suggest directions for school health and future research.

METHODS

Science Direct, PubMed, AMED, CINAHL, OVID, EMBASE, and Scopus were searched for peer-reviewed articles using combinations of the following key words: schoolbag, backpack, rucksack, knapsack, satchel, book bag, book pack and included combinations of children, pain, gait, and posture. Article references were also checked for further citations. All are in English, with the exception of one which is in German but is widely cited.

RESULTS

There are conflicting findings in the literature. The recommended load limit for schoolchildren to carry varies from 5% to 20% of their body weight, and the evidence linking backpack weight and back pain is inconclusive.

CONCLUSIONS

The shortcomings in the current literature should be addressed so that evidence-based guidelines can be provided to schoolchildren, parents, and teachers. It is suggested that general guidance may be more appropriate than a single load limit guideline.

Postural compensations and subjective complaints due to backpack loads and wear time in schoolchildren

PURPOSE

This study investigated the effects of carrying weighted backpacks of up to 20% of body weight on the posture and pain complaints of elementary-school children.

METHODS

Craniovertebral, forward trunk lean and pelvic tilt angles were measured from sagittal photographs of 62 children (8-11 years old) before and after walking while carrying backpacks containing 10%, 15%, or 20% of body weight. Pain severity after a 6-minute walk with the loaded backpack was recorded. Subjective complaints of pain were assessed using a visual analog scale after walking.

RESULTS

Repeated-measures ANOVA revealed statistically significant differences in postural angles and increased complaints of pain after walking with increased backpack loads.

CONCLUSION

These results indicate that typical backpack loads create worsening postural changes due to backpack loads and time spent carrying those loads, putting children at increased risk for injury and pain, the latter of which is a strong predictor for back pain in adulthood.

Biomechanical evaluation of different abduction splints for the treatment of congenital hip dysplasia

BACKGROUND

Abduction splints for the treatment of hip dysplasia normally operate on curbing the legs at the hip flexion and abduction. The forces are absorbed in different designs of shoulder straps and thus diverted to the shoulder and the spine. The present study is the first comparing these undesired forces of two spread orthoses and subsequently the transmitted forces to the infant's spine.

METHODS

Between March 2009 and October 2009 the hips of 290 infants were investigated by ultrasound within the first 3 days after birth. Thereof 20 infants with a hip dysplasia Graf type IIc, D or IIIa met our inclusion criteria and were investigated with a Tübinger and a Superior abduction splint. Biomechanical evaluation was performed by using a high-sensitive strain gauge sensor applied to the infant's orthoses between pelvic harness and shoulder straps.

FINDINGS

The transmitted forces to the infant's shoulders correlated significantly with their body mass (P<0.05). Maximal forces on the shoulder of the infants and subsequently transmitted forces on the spine were significantly higher (P<0.05) with the Tübinger splint (range 7.6N to 32.3N; arithmetic mean M: 13.7N) in comparison to the Superior orthosis (range 0.0N to 3.5N; M: 0.7N).

INTERPRETATION

The Superior orthosis works with primary load transmission to the pelvic bone. Using the Tübinger splint the shoulders of the newborn infants are loaded with a maximum of 93.9% of their body mass. This may influence the development of the growing infant's spine.

Postural assessment of lumbar lordosis and pelvic alignment angles in adolescent users and nonusers of high-heeled shoes

OBJECTIVE

The aims of this study were (1) to analyze the influence of wearing high-heeled shoes on lumbar lordosis and pelvic inclinations among adolescents aged between 13 and 20 years were users and nonusers of high-heeled shoes and (2) to correlate these postural angles with age.

METHODS

Fifty adolescents from the nonuser group (NUG) of high-heeled shoes and 50 from the user group (UG) were evaluated. Postural assessments were obtained by photogrammetry under 2 conditions-barefoot and with high-heeled shoes-and analyzed using the evaluation postural software. The measured angles included lumbar lordosis and the horizontal alignment of the pelvis. Descriptive analyses were carried out, with a significance level of 5%.

RESULTS

With high-heeled use, the NUG demonstrated rectification of the lumbar spine and pelvic retroversion, whereas the UG demonstrated hyperlordosis and pelvic anteversion. When barefoot, smaller lumbar lordosis angles for both groups were observed. However, the pelvic angles were lower for the UG group and higher for the NUG. The studied angles showed high reliabilities. Age was correlated with lumbar lordosis angles for the NUG in the barefoot condition and with pelvic alignments in both conditions for the UG.

CONCLUSION

For the subjects in this study, the use of high-heeled shoes is correlated with increased lumbar lordosis and pelvic anteversions. Lumbar lordosis angles are correlated with age for the NUG when barefoot.

The effect of school bag design and load on spinal posture during stair use by children

Thirteen male children ascending and descending stairs with loads that equalled 0%, 10%, 15% and 20% of their body weight were the subject of our research: the boys were wearing an asymmetrical single-strap athletic bag or a symmetrical double-strap backpack during our experiments with them. The maximum spinal tilt to the loading side and to the support side, and the range of spinal motions, were obtained by using a motion analysis system. Our results showed that symmetry of spinal posture was observed both when they ascended staircase with all loads and descended in a backpack. When carrying an athletic bag with 15% and 20% of their body weight while ascending the staircase, the lateral spinal tilt to the supporting side was significantly increased. We concluded that a symmetrical backpack with a load not exceeding 20% or an asymmetrical single-strap athletic bag with a load not exceeding 10% should be recommended for school children in order to promote safer staircase use. STATEMENT OF RELEVANCE: Children carrying heavy school bags may develop spinal problems. This study suggested that when they are using stairs, a symmetrical backpack with a load within 20% body weight is acceptable for them. When they are carrying an asymmetrical single-strap athletic bag, the bag's weight should not exceed 10% of the body weight in order to avoid excessive spinal tilt.

[Prevalence of idiopathic scoliosis and associated variables in schoolchildren of elementary public schools in Cuiabá, state of Mato Grosso, 2002]

OBJECTIVE

To estimate the prevalence of idiopathic scoliosis and its associated factors in schoolchildren of elementary public schools.

METHODS

Cross sectional two-phase study, the first of which in classrooms. Those considered Adams positive were invited for the second phase, which consisted of an interview for associated factors and a scoliosis exam. Those with a confirmed test in the second phase were submitted to x-rays for scoliosis and other factors. To estimate the prevalence, curves with > 5 and > 10 Cobb degrees were used as cut off.

RESULTS

In the first phase, 382 students were counted as Adams positive; of these 210 came for the second phase, 142 of which with a confirmed test. Using a chi-square test to compare the variables age, sex and color of the lost group (n = 172) to the group that accepted the invitation (n = 210), no statistical significance was observed, allowing statistical inference for the sample studied (n = 3,105). The estimated prevalence of scoliosis in the sample studied was 5.3% for curves > 5 Cobb degrees and 2.2% for curves > 10 Cobb degrees. Thoracic curves were observed in 44.8%, Risser grade 1 in 97.4%, and vertebral rotation degree I in 3.2%. Statistical significance was observed (p < 0.05) for the association of scoliosis with: physical activity, hump, and flexibility of the spine to the right.

CONCLUSION

The estimated prevalence of scoliosis in our study is comparable to those from other studies. However, its diagnosis and follow-up are important to health promotion and to the prevention of more severe disorders.

Back pain in children: a holistic approach to diagnosis and management

Back pain is a relatively common complaint presenting to the primary care practitioner and is addressed with increasing frequency in the pediatric literature. Back pain is not uncommon in adolescents and often is symptomatic of a relatively benign musculoskeletal etiology. Back pain in children less than 10 years of age and most especially less than 4 years of age can signal a more alarming underlying condition. Evaluation requires a complete history including psychosocial and cultural considerations. Additionally a thorough clinical examination, strategic lab work and judicious imaging are imperative. Management and appropriate referral is specific to the underlying disease process. A holistic, individualized plan of care with inherent involvement of the child and parent/caregiver is essential to ensure safety and enhance outcomes.

Prevalência e fatores associados à dor lombar em escolares

O objetivo foi verificar a prevalência de dor lombar em adolescentes e sua relação com a prática de esportes e atividades sedentárias. Realizou-se um estudo transversal com 1.236 escolares das 5ª a 8ª séries do Ensino Fundamental de Bauru, São Paulo, Brasil. Foram utilizados um protocolo estruturado e o questionário nórdico de sintomas musculoesqueléticos. A análise foi realizada mediante uma abordagem descritiva, bivariada e multivariada por regressão logística binária. Notou-se que a prevalência de dor lombar foi de 19,5%, sendo 7% nos meninos e 12,5% nas meninas, com diferença estatisticamente significante entre os gêneros (p < 0,00001), a faixa etária (p = 0,0057) e prática de esportes (p = 0,0001). Na análise bivariada e multivariada, observaram-se associações independentes entre dor lombar e o gênero feminino, horas na frente da TV e prática de esportes. A dor lombar em escolares pode ter consequências importantes para dores crônicas em adultos, e a compreensão das relações entre as variáveis oferecerá elementos úteis de medidas visando à manutenção, à melhora e à promoção do bem-estar dos estudantes.

School Bag Weight and the Occurrence of Shoulder, Hand/Wrist and Low Back Symptoms among Iranian Elementary Schoolchildren

BACKGROUND

Schoolchildren usually use school bags to carry their school materials. Carry-ing heavy school bags can cause several problems such as musculoskeletal problems among schoolchildren. The aim of this study was to investigate the association between the weight of school bags and the occurrence of low back, shoulder and hand/wrist symptoms among pri-mary school children.

METHOD

This cross-sectional, descriptive-analytical study was conducted among a sample of 307 elementary school children in Tabriz, Iran. Data were collected using a questionnaire and from measurement of the school bag weight, body weight and height of each participant. Data were analysed using SPSS software.

RESULTS

The average load carried by schoolchildren was 2.9 kg, representing approximately 10% of the children's body weight. Girls and lower grade children carried a greater percent-age of their body weights. Approximately 86% of the children reported some kind of muscu-loskeletal symptoms. The occurrence of shoulder, wrists/hands, and low back pain among school-children was 70%, 18.5% and 8.7%, respectively. The results of binary logistic regres-sion indicated that the school bag weight (expressed as a percentage of body weight) was only significantly associated with hand/wrist symptoms (P<0.05). Girls were more likely to com-plaint from low back pain than boys were. Age was significantly negatively associated with hand/wrist symptoms. Body mass index was also significantly associated with shoulder symptoms.

CONCLUSION

The results indicate a high prevalence of musculoskeletal symptoms among elemen-tary schoolchildren. Preventive measures and appropriate guidelines with regard to safe load carriage in schoolchildren are therefore needed to protect this age group.

Metabotropic glutamate receptor-5 and protein kinase C-epsilon increase in dorsal root ganglion neurons and spinal glial activation in an adolescent rat model of painful neck injury

There is growing evidence that neck pain is common in adolescence and is a risk factor for the development of chronic neck pain in adulthood. The cervical facet joint and its capsular ligament is a common source of pain in the neck in adults, but its role in adolescent pain remains unknown. The aim of this study was to define the biomechanics, behavioral sensitivity, and indicators of neuronal and glial activation in an adolescent model of mechanical facet joint injury. A bilateral C6-C7 facet joint distraction was imposed in an adolescent rat and biomechanical metrics were measured during injury. Following injury, forepaw mechanical hyperalgesia was measured, and protein kinase C-epsilon (PKCɛ) and metabotropic glutamate receptor-5 (mGluR5) expression in the dorsal root ganglion and markers of spinal glial activation were assessed. Joint distraction induced significant mechanical hyperalgesia during the 7 days post-injury (p < 0.001). Painful injury significantly increased PKCɛ expression in small- and medium-diameter neurons compared to sham (p < 0.05) and naïve tissue (p < 0.001). Similarly, mGluR5 expression was significantly elevated in small-diameter neurons after injury (p < 0.05). Spinal astrocytic activation after injury was also elevated over sham (p < 0.035) and naïve (p < 0.0001) levels; microglial activation was only greater than naïve levels (p < 0.006). Mean strains in the facet capsule during injury were 32.8 ± 12.9%, which were consistent with the strains associated with comparable degrees of hypersensitivity in the adult rat. These results suggest that adolescents may have a lower tissue tolerance to induce pain and associated nociceptive response than do adults.