Postural and subjective responses to realistic schoolbag carriage

Neglected problem: Influence of school bag on lumbar segment in children

BACKGROUND AND OBJECTIVES

School bag (SB) load causes significant changes in the height and symmetry of the intervertebral discs at each level of the spine from T12-L1 to L5-S1. This study aims to determine the change in the size of the lumbar segment angle at a particularly critical point L3-L4 of the spine in relation to the load of the average weight of SB in healthy male children (students) at standing and after 2-minute gait.

METHODS

47 boys, aged 12.2 ± 0.92 years, underwent photogrammetric measurements in the sagittal plane in statics and dynamics, walking on a laboratory treadmill. Measurements were repeated with the weight of SB with a constant load of 6,251 kg, which represents 13.78% of the average body weight of our sample. The lumbar angle (LA) connecting the point of the big toe, the lumbar point L3-L4 and the processus spinosus C7 was measured. In gait, LA was measured in the phases of the middle support and the initial contact of the heel.

RESULTS

T-test of paired samples was used to estimate the change in LA at standing from 4.953° and walking phases from 6.295° to 7.332° in relation to the unloaded state, and the value of the effect size (ES) indicates that the impact of SB load is significant.

CONCLUSIONS

Cumulatively, microtraumas caused by SB load significantly affect the increase in intervertebral pressure at the L3-L4 point, which is susceptible to degenerative processes and which can be the cause of lumbar syndrome (LS). Preventive measures are needed in order to lighten SB in this population and introduce up to 10% of students' body weight into the safe zone.

Non-specific low back pain: cross-sectional study of 11,423 children and youth and the association with the perception of heaviness in carrying of schoolbags

Background

Carrying a schoolbag is a daily activity for most children and adolescents.The perception of a schoolbag’s weight depends upon the individual and is a relevant theme in schoolchildren. Describing the association between the perception of heaviness in carrying a schoolbag and NLBP can facilitate the planning of preventive programs, quite different from those based on specific weight limits for schoolbags in children and youth.

Objective

To determine the prevalence of non-specific low back pain (NLBP) and to analyse the association between the perception of heaviness in carrying of schoolbags and NLBP in Polish children and youth aged 10–19.

Methods

This study included 11,423 children and youth (6,252 girls and 5,171 boys) from Poland. An original questionnaire was used to assess NLBP prevalence.

Results

Among 11,423 of the respondents, 41.5% of the respondents admitted that they had experienced NLBP in the period of the last 12 months. The percentage of individuals reporting NLBP increased with age of participants, p < 0.001. Girls reported NLBP more often than boys (p < 0.001). Students with NLBP declared that their school backpack was heavy more often than students without LBP. Students who thought that their backpacks weighed too much manifested a 1.44 (95% Cl [1.33–1.55]) times higher probability to experience NLBP.

Conclusion

In the examined group of schoolchildren a frequent occurrence of NLBP (41.5%) was noted. Its occurrence was related to female sex and age. Students who thought that their backpacks weighed too much manifested higher probability to develop NLBP.

Parents' knowledge and attitudes when choosing their children's school bag: An introductory study

Background/Aim: A school bag is a device whose purpose is to store things that are necessary for a child in performing daily productive activities. The aim of the research was to examine how much parents are informed about the school bag and which specifications are crucial when choosing a school bag for their children. Material and methods: The prospective study included 150 parents of students aged 11 to 12 from Banja Luka. For the purposes of the research, a questionnaire with closed and open questions was used. Results: More than 97 % of the surveyed parents belonged to the age range of 30 to 49 years. The largest number of surveyed parents have had secondary education 44 %, but the number of university-educated parents was also very high 39.3 %. Ninety-six percent of students used a backpack. School bags in 97.4 % of cases were purchased in stores. Only in 10 % of cases, school bags fully meet the basic criteria. In the remaining 90 % of cases, there was an absence of at least one or more desired characteristics. Using the Chi-squared test (ch2 = 245.45; p < 0.001), a significant difference between the desired and the achieved result was statistically proven. 77.3 % of parents did not receive information about the school bag. Salespeople (11.3 %), other parents and friends (9.3 %) were the main source of information before purchasing a school bag. In the future, 54 % of parents would like to get information about the school bag through lectures and practical workshops for children and parents. Conclusion: Greater information enables adequate selection and reduces the possibility of marketing tricks and influences on consumers when choosing the desired product such as a school bag. Parents have an important role to play in ensuring unhindered growth and development during the educational process and in raising children's awareness and supervision of the proper use of the school bag.

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.

Does Wearing a Portable Metabolic Unit Affect Youth's Physical Activity or Enjoyment During Physically Active Games or Video Games?

Portable metabolic units (PMUs) are used to assess energy expenditure, with the assumption that physical activity level and enjoyment are unaffected due to the light weight and small size.

PURPOSE

To assess differences in physical activity level and enjoyment while wearing and not wearing a PMU.

METHOD

Youth (8-17 y; N = 73) played children's games or active video games while wearing and not wearing a PMU (crossover design). Participants wore an accelerometer and heart rate monitor and responded to questions about enjoyment on a facial affective scale. A repeated-measures analysis of variance was used to determine if accelerometer measures, heart rate, or enjoyment differed between conditions overall and by sex and weight status.

RESULTS

Steps per minute were lower while wearing the PMU than not wearing the PMU (40 vs 44, P = .03). There was an interaction between PMU condition and weight status for enjoyment (P = .01), with overweight participants reporting less enjoyment when wearing the PMU compared with not wearing the PMU (72 vs 75 out of 100). Heart rate, vector magnitude, and counts per minute were not different.

CONCLUSION

There may be psychosocial effects of wearing the PMU, specifically in overweight participants. Activity level was minimally affected, but the practical significance for research is still unknown.

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.

Do schoolbags cause back pain in children and adolescents? A systematic review

OBJECTIVE

To investigate whether characteristics of schoolbag use are risk factors for back pain in children and adolescents.

DATA SOURCES

Electronic searches of MEDLINE, EMBASE and CINAHL databases up to April 2016.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Prospective cohort studies, cross-sectional and randomised controlled trials conducted with children or adolescents. The primary outcome was an episode of back pain and the secondary outcomes were an episode of care seeking and school absence due to back pain. We weighted evidence from longitudinal studies above that from cross-sectional. The risk of bias of the longitudinal studies was assessed by a modified version of the Quality in Prognosis Studies tool.

RESULTS

We included 69 studies (n=72 627), of which five were prospective longitudinal and 64 cross-sectional or retrospective. We found evidence from five prospective studies that schoolbag characteristics such as weight, design and carriage method do not increase the risk of developing back pain in children and adolescents. The included studies were at moderate to high risk of bias. Evidence from cross-sectional studies aligned with that from longitudinal studies (ie, there was no consistent pattern of association between schoolbag use or type and back pain). We were unable to pool results due to different variables and inconsistent results.

SUMMARY/CONCLUSION

There is no convincing evidence that aspects of schoolbag use increase the risk of back pain in children and adolescents.

Guidelines for schoolbag carriage: An appraisal of safe load limits for schoolbag weight and duration of carriage

BACKGROUND

There is no global agreement on a schoolbag weight limit and little assessment of its utility. The duration of carriage is another factor yet there is no previous systematic assessment of the utility of cut-off values for it in identifying schoolbag-related discomfort.

OBJECTIVES

The objectives were to establish if there was a threshold for musculoskeletal discomfort based on (i) percentage bodyweight (% BW) of the schoolbag; (ii) duration of carriage; or (iii) combined % BW and duration.

METHODS

Using data from 462 primary school children, a novel experimental approach was used to explore the utility of conventional schoolbag weight limit guidelines and duration of carriage. A receiver operating characteristic (ROC) curve was constructed to examine the predictive performance of schoolbag weight and duration of carriage.

RESULTS

The mean schoolbag weight (4.8±1.43  kg) represented a mean 12.4±4.18% BW. Only 30.7% of the sample carried schoolbags that were ≤10% BW. The majority (76%) carried schoolbags to school for ≤10 minutes. No % BW, duration of carriage or mechanical burden criterion provided a threshold cut-off point for accurately predicting schoolbag-related discomfort.

CONCLUSIONS

Guidelines for safe schoolbag carriage that are based on mechanical factors alone could not be upheld. The association between duration of carriage and back discomfort warrants further investigation.

Backpack-back pain complexity and the need for multifactorial safe weight recommendation

The study analysed backpack-related back pain in school children by investigating the possibility of multiple interactions among causative factors, which may be responsible for the non-conclusive findings on the issue. Using data from 444 prepubescent schoolchildren, a mixed method design combining survey, observation and direct measurement strategies was implemented. Using a multivariate structural equation modelling approach, the study investigated interactions among anthropometry, posture, backpack volume, rating and back pain constructs, with each construct made of 2-4 indicators. Additionally, regression analysis was used to determine the feasibility of considering the two additional factors of age and body mass index along with the globally accepted recommendation of a load of 10-15% of body weight. Our model demonstrated an acceptable model fit and revealed direct and indirect effects of the factors. Obese children were recommended to carry a one-third lighter load than other children. The application of systematic/multiple strategies provided an explanation for some of the issues associated with school children's backpack-related back pain.

Schoolbag carriage and schoolbag-related musculoskeletal discomfort among primary school children

Schoolbag carriage is a common occurrence and has been associated with musculoskeletal discomfort in children. The current study investigated the relationship between schoolbag-related musculoskeletal discomfort and individual, physical and psychosocial risk factors in primary school children in Ireland. A cross-sectional survey and pretest-posttest quasi-experimental design was used. The site and intensity of musculoskeletal discomfort was assessed before and after schoolbag carriage to provide a dose-response assessment of schoolbag-related discomfort for the first time. Objective measurements of the children, schoolbags and other additional items were made, and a researcher assisted questionnaire was completed on arrival at school. A total of 529 children (male 55.8%: female 44.2%) with a mean age of 10.6 years ± 7.14 months were included. The majority had backpacks (93.8%) and 89.7% (n = 445) carried the backpack over 2 shoulders. The mean schoolbag weight (4.8 ± 1.47 kgs) represented a mean % body weight (%BW) of 12.6 ± 4.29%. Only 29.9% carried schoolbags that were ≤10%BW. A significantly greater proportion of normal weight children carried schoolbags that were >10%BW compared to overweight/obese children (p < 0.001). The mean %BW carried was 18.3 ± 5.03 for those who had an additional item. The majority (77.5%) carried schoolbags to school for ≤10 min. The prevalence of baseline musculoskeletal discomfort was high (63.4%). Schoolbag-related discomfort was reported more frequently in the shoulders (27.3%) than in the back (15%). The dose-response assessment indicated that both statistically and meaningfully significant increases in discomfort were observed following schoolbag carriage. Multiple logistic regression models indicated that psychosocial factors and a history of discomfort were predictors of schoolbag-related back discomfort, while gender (being female) and a history of discomfort were predictors of schoolbag-related shoulder discomfort. None of the physical factors (absolute/relative schoolbag weight, carrying an additional item, duration of carriage, method of travel to school) were associated with schoolbag-related discomfort. This study highlights the need to consider the multi-factorial nature of schoolbag-related discomfort in children, and also the need to identify background pain as its presence can inadvertently influence the reporting of 'schoolbag-related' discomfort if it is not accounted for.

Short-term effects of backpack carriage on plantar pressure and gait in schoolchildren

PURPOSE

To assess the effects of backpack carriage on plantar pressure distributions and spatio-temporal gait parameters among children.

PARTICIPANTS

Two hundred-eighteen schoolchildren, aged 6-13, and attending primary and secondary schools in the city of Cagliari (Italy).

METHODS

Participants were tested at school, during regular days. A pressure plate and wearable inertial sensors were used to measure plantar pressures and spatio-temporal parameters of gait. Measures were obtained during both quiet standing and walking, and both with and without a backpack. The latter contained those items a child had on the testing day.

RESULTS

Participants carried a mean mass in their backpacks of 5.2 kg, and more than half had a backpack/body mass ratio higher than 15%. While spatio-temporal gait parameters were not affected by backpack carriage, significant increases (up to 25%) in plantar pressures were found during both static standing and walking, especially in the forefoot.

CONCLUSION

Under realistic conditions, the impact of backpack carriage was more evident on foot-ground interaction than on gait features. However, long-term consequences of altered plantar pressure need to be assessed in future work, considering the actual durations typically spent carrying school items.

Backpack-related musculoskeletal symptoms among Nigerian secondary school students

Musculoskeletal discomfort in schoolchildren is significantly related to the weight and mode of carrying backpack to school. Prevalence and patterns of musculoskeletal discomfort among Nigerian secondary school students carrying backpack was investigated. Systematic sampling technique was used in the selection of the participating junior secondary schools for this study. Participants comprised 1,785 students aged 10-15 years. Standardised Nordic musculoskeletal questionnaire was used to collect information on musculoskeletal pain. Backpack weight and participants' body weight were measured using a weighing scale. The visual analogue scale was used to assess pain intensity. Gender differences in backpack weight, backpack percentage and musculoskeletal discomfort were studied using Mann-Whitney U test; Kruskal-Wallis test was used to study the influence of backpack carrying style on musculoskeletal discomfort; and Spearman rho correlation to determine the relationships between backpack weight, backpack to body weight ratio, age and pain intensity. There were 882 boys and 903 girls recruited into the study. Shoulder pain was the most prevalent discomfort (63.5 %), and pain was significantly higher in girls (p = 0.013). There were weak relationships between pain intensity, body weight and backpack to body weight ratio (r range 0.433-0.442; p < 0.001), and a weak negative relationship between pain intensity and age [r = -0.135; p < 0.001; 95 % confidence interval (CI) -0.168, -0.075]. There was a strong relationship between backpack weight and age (r = 0.892; p < 0.001; 95 % CI -0.129, -0.013); however, there was a weak relationship between backpack weight and body weight (r = 0.136; p < 0.001). Prevalence of shoulder pain was high, particularly among the girls, in this sample. We suggest that factors other than the weight of backpack may predispose to musculoskeletal pain. Parents, teachers and clinicians can influence the mode of carrying backpack by secondary school students.

Effect of backpack load on the head, cervical spine and shoulder postures in children during gait termination

Twelve boys with an average age of 9.9 years were instructed to carry backpacks that weighed 0%, 10% and 15% of their body weights (BWs) to complete planned and unplanned gait termination experiments. The craniohorizontal, craniovertebral and sagittal shoulder posture angles at the sagittal plane as well as the anterior head alignment and coronal shoulder posture angles at the coronal plane were analysed. Results revealed significantly smaller craniohorizontal and sagittal shoulder posture angles during planned gait termination and a significantly smaller sagittal shoulder posture angle during unplanned gait termination under loaded conditions compared with those at 0% BW backpacks. Furthermore, the coronal shoulder posture angles at 10% and 15% BW during planned and unplanned gait terminations were significantly larger than those at 0% BW. Therefore, subjects were more likely to have a forward head posture, rounded shoulder posture and increased lateral tilting of the shoulders during gait termination as backpack loads were increased. However, gait termination, whether planned or unplanned, did not elicit a remarkable effect on posture.

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.

Relative weights of the backpacks of elementary-aged children

The purpose of the study was to describe the range of relative backpack weights of one group of elementary-aged children and the extent to which they exceeded recommended levels. A second purpose was to explore whether gender and age help predict the relative weight of children's backpacks. Ninety-five 8- to 12-year-old elementary school students (56% girls; 88% car or bus riders) participated. Their school backpacks were weighed, and their age, gender, and mode of transportation to school were recorded. Only 40% of the sample carried backpacks that were less than 10% of their body weights. Five percent of the students' backpacks exceeded 20% of their body weights. Neither age group nor gender significantly predicted relative backpack weight or relative weight levels. Recommendations are made for ways to reduce the weight these young children carry.

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.

The use of schoolbags and musculoskeletal symptoms among primary school children: are the recommended weight limits adequate?

This cross-sectional study investigated the use of schoolbags and the prevalence of musculoskeletal symptoms among a sample of 307 Iranian primary school children aged 7-12 years. The average load carried by the children was 2.9 kg (representing on average 10.1% of the child's body weight). Most children chose to carry the schoolbag across two shoulders, although significant numbers also carried it on one shoulder or in the hand. Although the amount of load carried by school children was within the currently suggested load limit of 10% to 15% of the child's body weight, the prevalence of musculoskeletal problems was very high among the study population. Multiple logistic regression models indicated that the method of carrying the schoolbag was significantly associated with hand/wrist and shoulder symptoms, and that the time spent carrying a schoolbag was associated with hand/wrist and upper back symptoms. Schoolbag weight (expressed as a percentage of body weight) was only associated with hand/wrist symptoms. The results suggest that the current recommended weight limit may not be appropriate for school children in primary school, and that guidelines ought to consider factors other than relative schoolbag weight that influence the use of schoolbags among this age group.

PRACTITIONER SUMMARY

The carrying of schoolbags by primary school children and their musculoskeletal symptoms were investigated. The results provide evidence that the current weight limit may not be appropriate for younger school children, and that such guidelines should consider a broader combination of the factors that influence the use of schoolbags.

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.

A kinetic comparison of back-loading and head-loading in Xhosa women

The purpose of this study was to compare the kinetic responses associated with ground reaction force measurements to both head-loading and back-loading in a group of Xhosa women. Altogether, 16 women were divided into two groups based on their experience of head-loading. They walked over a force plate in three conditions: unloaded or carrying 20 kg in either a backpack or on their head. The most striking finding was that there was no difference in kinetic response to head-loading as a consequence of previous experience. Considering the differences between the load carriage methods, most changes were consistent with increasing load. Head-loading was, however, associated with a shorter contact time, smaller thrust maximum and greater vertical force minimum than back-loading. Both loading conditions differed from unloaded walking for a number of temporal variables associated with the ground contact phase, e.g. vertical impact peak was delayed whilst vertical thrust maximum occurred earlier. STATEMENT OF RELEVANCE: Consideration of the kinetics of head and back load carriage in African women is important from a health and safety perspective, providing an understanding of the mechanical adaptations associated with both forms of load carriage for a group of people for whom such load carriage is a daily necessity.

Subjective perceptions of load carriage on the head and back in Xhosa women

The purpose of this study was to compare the subjective perceptual responses to both head-loading and back-loading in a group of Xhosa women. Thirty two women were divided into three groups based on their experience of head-loading and walked on a treadmill on two occasions, head-loading and back-loading, at a self selected walking speed for 4 min with a variety of loads until pain or discomfort caused the test to be terminated or a load of 70% body mass was successfully carried. After each workload there was a 1 min rest period during which the women indicated feelings of pain or discomfort in particular areas of the body via visual analogue scales. At the end of each test the women were asked to complete further questionnaires relating to pain and discomfort and on completion of the second test were also asked to compare the two loading conditions. Finally the women were interviewed to establish their history of load carriage and associated pain and discomfort. The data indicate that whilst back-loading was generally associated with more areas of discomfort than head-loading, the pain and discomfort in the neck associated with head-loading was the predominant factor in the termination of tests and that this was independent of head-loading experience. This early termination meant that, on average, the women could carry greater loads on their backs than on their heads. The study suggests that further work needs to be carried out to establish viable alternatives to head-loading for rural dwellers in Africa.

Postural sway modifications induced by backpack carriage in primary school children: a case study in Italy

The aim of this investigation is to assess modifications in sway parameters introduced by backpack carriage in Italian primary school children (6-10 years old, n = 447). Two 30-s trials (without and with backpack) were performed directly at a school on a regular school day to collect data on sway area, centre of pressure path length and maximum displacement range in antero-posterior and medio-lateral directions. The results show a significant load-induced increase in all sway parameters and the existence of a linear relationship between sway area and backpack weight. Since postural sway represents an effective indicator of balance abilities, the alterations observed suggest that backpack carriage originates balance impairment and thus may increase the risk of unintentional falls in children. STATEMENT OF RELEVANCE: Loss of balance is among the primary causes of unintentional falls and postural sway represents an effective indicator of balance abilities. In this study, sway parameters were assessed in primary school children wearing backpacks. The differences that were observed show that backpack carriage potentially increases the risk of falls.