Relative weights of the backpacks of elementary-aged children

Load modulation affects pediatric lower limb joint moments during a step-up task

Performance in a single step has been suggested to be sensitive measure of movement quality in pediatric clinical populations. Although there is less information available in children with typical development, researchers have postulated the importance of analyzing the effect of body weight modulation on the initiation of stair ascent, especially during single limb stance where upright stability is most critical. The purpose of this study was to investigate the effect of load modulation from -20% to +15% of body weight on typical pediatric lower limb joint moments during a step-up task. Fourteen participants between 5-21 years with no known history of neurological or musculoskeletal concerns were recruited to perform multiple step-up trials. Peak extensor support and hip abduction moments were identified during the push-off and pull-up stance phases. Linear regressions were used to determine the relationship between peak moments and load. Mixed effects models were used to estimate the effect of load on hip, knee, and ankle percent contributions to peak support moments. There was a positive linear relationship between peak support moments and load in both stance phases, where these moments scaled with load. There was no relationship between peak hip abduction moments and load. While the ankle and knee were the primary contributors to the support moments, the hip contributed more than expected in the pull-up phase. Clinicians can use these results to contextualize movement differences in pediatric clinical populations including cerebral palsy and highlight potential target areas for rehabilitation for populations such as adolescent athletes.

Assessment of the elementary school students’ schoolbag weight in the urban environment in Poland: A cross-sectional study carried out as a part of the ‘Lightweight Schoolbag’ and ‘Let’s Get the Kids Moving’ projects

BACKGROUND: Carrying a properly weighted schoolbag is an important factor in preventing the occurrence of muscular skeletal disorder in early school age children. OBJECTIVE: The purpose of this cross- sectional observational study was to examine the schoolbag weight and to determine the percentage of children were carrying overloaded schoolbag. METHODS: The study group included pupils from five primary public schools in Wrocław, Poland. Anthropometrical measurements such body weight (BW) and height were conducted on 650 children (51.1% of boys). Children’s age, gender, Cole’s Index was juxtaposed with schoolbag weight. The mean age of the examined students was 8.7±0.8 years (range 7 to 10 years). RESULTS: The mean schoolbags weight was 3.7±0.92 kg, which represented 13.0±3.8% of pupils’ BW. The percentage of pupils carry the schoolbags weighing more than 10% of their BW was 77.9%. More than a quarter of Polish children carry school backpack above 15% of their BW. The majority (96.8%) had schoolbags which may be carried on both shoulders. A significant negative correlation was observed between relative schoolbag weight and Cole’s Index (rho = –0.44, p < 0.05). CONCLUSIONS: The problem of overloaded schoolbags among elementary school children was frequent. Pupils ought to be educated in the proper packing of their school backpacks. Additionally, parents and teachers should pay attention regarding the contents carried by children in their respective schoolbags.

Normative values for relative schoolbag weight in primary school children aged 6-14 from Czech Republic: A pilot study

Little evidence from observational studies has been provided regarding ‘optimal’ relative schoolbag load during primary education. Also, no study to date has provided reference-based standards for relative schoolbag weight. Therefore, the main purpose of the study was to establish normative values of relative schoolbag weight in a sample of children. In this cross-sectional study, we recruited 584 primary school students aged 6–14 (mean_age±SD = 9.6±2.4 yrs, mean_height±SD = 1.4±0.2 m, mean_weight±SD = 37.5±13.3 kg, mean_{body-mass index}±SD = 17.6±3.1 kg/m², 44.4% girls) chosen from five schools in the city of Brno. Schoolbag weight and child’s body weight were objectively measured by using digital scale. Relative schoolbag weight was calculated by dividing schoolbag weight with child’s body weight and the result was expressed in percentage. Lambda, Mu and Sigma (LMS) method was used to create sex- and age-percentile curves. Boys carried slightly heavier schoolbag, compared with girls (mean difference 0.2 kg, p = 0.020). No significant differences between sexes in relative schoolbag weight were observed (p = 0.240). Median values (P50) for boys and girls were similar and the largest observed between ages 6–9 in boys (15–17%) and 6–8 in girls (16–18%). The percentage of children carrying relative schoolbag weight beyond 10% of their body weight was very high, especially between ages 6–10 in boys (85.1–100%) and 6–11 in girls (86.8–95.4%). This study provides first sex- and age- relative schoolbag weight normative values in primary school children. Future studies should use similar methods for generating comparable data.

Schoolbag weight carriage in Portuguese children and adolescents: a cross-sectional study comparing possible influencing factors

BACKGROUND

Schoolbags and the consequences of carrying them, particularly those associated with overload, are often studied as a health concern. Modifications in gait and posture were reported when children carried loads that corresponded to more than 10% of their body weight (BW). The aims of this study were to verify the load that is carried by Portuguese students and how it is influenced by factors such as school grade, school schedule, lunch site, physical education, sex and body mass index (BMI). Acquiring a more specific knowledge of the Portuguese context and understanding the influence of these factors may allow us to generate proposals to control them in ways that benefit students.

METHODS

The load carried by students in the 5th grade (10.6 ± 0.4 years) and 9th grade (14.7 ± 0.6 years) were weighed with a luggage scale on all days of the week, resulting in 680 evaluations. Data related to the school day were also collected, such as the student's lunch site, how he or she got to school and his or her school schedule for that day. Individual height and weight were also assessed.

RESULTS

The 5th grade students carried greater loads than the 9th grade students, resulting in a substantial difference relative to their BW. The school loads of the 5th grade students were mostly greater than 10% of their BWs. Girls tended to carry heavier loads than boys, and overweight students also tended to carry heavier loads. Students who could eat lunch at home carried less weight, and on physical education days, the total load carried increased, but the backpacks of the 5th grade students were lighter.

CONCLUSIONS

The results of the current study describe excessive schoolbag weight among Portuguese students and expound on some of the factors that influence it, which can help researchers and professionals design a solution to decrease children's schoolbag loads.

Effect of backpack carrying on forced vital capacity in cystic fibrosis: A randomized crossover-controlled trial

BACKGROUND

Backpack carrying impacts lung function in healthy children but the effect in children with cystic fibrosis (CF) is unknown.

METHODS

Three backpack positions were tested: no backpack (NB), a 12.5% body-weight backpack carried bilaterally (BB) or unilaterally (UB), at rest and during a 10 minute walk. Primary outcome was forced vital capacity (FVC). Secondary outcomes included comparison of cardio-respiratory variables within and between groups.

RESULTS

Nine children with CF (13.3±2.6 years; FEV1 66±22%) and 18 healthy children (13.8±1.8 years; FEV1 107±30%) were included. FVC was reduced with UB compared to NB (68.5±23.3% vs 72.1±24.3%, p = 0.024) in children with CF. FEV1, MIP and MEP decreased more with UB in children with CF than in healthy peers. Increases in VO2, VCO2 and minute ventilation with UB were greater in the CF group during walking.

CONCLUSIONS

Unilateral backpack wearing affects FVC in children with CF and requires greater cardio-respiratory adjustments compared to healthy peers.

Ergonomics evaluation of school bags in Tehran female primary school children

BACKGROUND

More than 90% of the elementary school students in the world and most of the Iranian students use backpacks. Heavy school bags, failure to apply ergonomics standards in student's backpacks, and also mismatch between anthropometrics dimensions and schoolbag size are important issues for children's health.

OBJECTIVE

The purpose of this study was to gather baseline information on the average weight carried by female primary students. It also aimed to evaluate ergonomics standards for student backpacks.

METHODS

A cross-sectional study was conducted on 212 Iranian girl students aged 6- 11 years. Body weight and bag weight were measured with electronic scales and body mass index calculated with WHO software 2007. A questionnaire was constructed to gather information about the backpacks. Body dimensions were measured with VICON motion Analyze system (460). Ergonomics factors were recorded using a checklist.

RESULTS

80.8% of the students used a backpack at a higher weight than recommended by the standards of 10% of body weight. The most common type of schoolbag used was double strap packs (92.5%). The majority of the students carried packs on their backs; however, most of them did not make any adjustments (79.8%). The results have shown a mismatch between the anthropometric measures and the student's backpack dimensions.

CONCLUSIONS

Parents, students and school staff should be informed about these critical issues as well as suitable controls should be implemented in buying and using the bags.

Current Backpack Weight Status for Primary Schoolchildren in Colima, Mexico

The purpose of the study was to identify the current status of backpack weight in primary schoolchildren in Colima, Mexico, in relation to gender, school grade level, and body mass index. A cross-sectional study was conducted on 240 randomly selected children from 20 primary schools. The participating children's parents signed statements of informed consent. Descriptive statistics, the χ(2) test, Student's t-test, and Kruskal-Wallis test were used. The mean age was 8.55 ± 2 years (range: 5-12 years). Seventy-eight percent of the schoolchildren presented with a backpack overload that was greater than 10% of their body weight. No significant differences were found in relation to gender. Four out of every five schoolchildren presented with backpack overload, exposing them to a potential health problem. Education and public policy prevention strategies for this situation should be implemented in Mexico and other regions of the world with the same problem.