Effect of work station design on sitting posture in young children

Ergonomic evaluation of school furniture in Slovenia: From primary school to university

BACKGROUND:

Adequate school furniture is important to prevent musculoskeletal discomfort among students.

OBJECTIVE:

The aim of the study was to assess the suitability of school furniture compared to body dimensions of students.

METHODS:

A cross-sectional study included a total of 442 students from primary school, secondary school, and university. Nine body dimensions along with five furniture dimensions were measured and equations for mismatch criteria were applied.

RESULTS:

In primary school, differences in body dimensions were more evident among students of different age, while in secondary school and university, differences between male and female students became more apparent. The mismatch for desk height ranged from 100.0% at primary school to 48.0% at university. Similarly, the seat height mismatch was the most evident in primary school (89.7% –94.6%), lower at university (52.0%) and the lowest in secondary school (18.0%). The seat depth mismatch was present among all groups, ranging from 23.1% to 40.4%, and was in general more pronounced in males. Seat to desk clearance mismatch was the most evident among secondary school students. In primary school, seat and desk height were generally too high for most of students.

CONCLUSIONS:

Specific differences in body dimensions among groups of students of different age and gender were observed and a high student-furniture mismatch was identified in all educational institutions. Implementation of adjustable school furniture, covering at least two size marks, is needed to provide ergonomic and healthy learning conditions and to further enhance the comfort and well-being of students in the classroom.

Asymmetry and Tightness of Lower Limb Muscles in Equestrian Athletes: Are They Predictors for Back Pain?

Athletes may suffer from low back pain (LBP). Some studies have considered restricted range of motion (ROM) as a risk factor for LBP in athletes; however, ROM has not been evaluated in equestrian athletes (EAs) with LBP. The aims of this research in EAs were (I) to analyze the relationship between lower limb ROM (tightness and asymmetry) and LBP and (II) to determine the reference values for lower limb ROM indicating high risk of LBP. Forty-three young (9–18 years old) EAs were voluntarily recruited in technical training camps. The EAs were assessed for 11 passive lower limb ROMs using the ROM-SPORT I Battery. LBP data were taken at the end of a 1-year period through a questionnaire. Binary logistic regression and receiver operating characteristic curves were calculated. Sixty-seven percent of EA had suffered LBP. Hip adduction (OR = 1.347, medium; p = 0.015) and knee flexion (OR = 1.109, small; p = 0.023) were predictors of LBP in EAs. A hip adduction of 26° and knee flexion of 128° were found to be the optimal cutoff values for predictive screening of EAs at high risk of LBP.

Relevance of adding a triangular dynamic cushion on a traditional chair: A 3D-analysis of seated schoolchildren

BACKGROUND

Low back pain is highly prevalent in the general population and is even reported as early as at primary school. A poor sitting position has been suggested as an etiologic factor. This study analysed, in primary schoolchildren, the influence of a triangular dynamic cushion that aims to help children maintain their physiological lumbar lordosis and to induce movement to reduce the static effect of the sitting position.

METHODS

Thirty 8-year-old children took part in this study. A 3D analysis combined with electromyography was used to evaluate the biomechanics and the related muscle activation in two sitting positions (with and without a triangular cushion on a horizontal stool) during a 15-minute working task. In addition, the force of the feet on the ground was assessed with a force plate.

FINDINGS

The cushion improved the trunk-thighs angle, lumbar lordosis, anterior pelvis tilt, and feet support on the ground (p<0.0001). In addition, sitting on the cushion appeared to be more dynamic (p<0.05) and induced a decrease of the lumbar paravertebral muscle activity (p<0.01).

INTERPRETATION

Sitting on a dynamic triangular cushion tends to favour the "ideal" siting position usually described in the literature and to decrease the level of paravertebral muscle recruitment. Seeing that sitting position is a risk factor to develop low back pain, the cushion could be a solution to prevent it.

The Occurrence of Back Pain in School Children and Exposure to Risk Factors in Schools can they be Measured?

Back pain is a significant financial burden on industry and the economy, but more importantly it is the cause of suffering and disability to countless individuals. Therefore if the symptoms and risk factors of back pain could be identified at an early stage, the opportunities for remedial action would be improved. The study aims to identify the extent of back pain experienced by 11 to 14 year old school children, and establish the intensity, duration and frequency of exposure to mechanical risk factors present in schools. The following criteria were formulated to meet the study objectives, The method should record the intensity, duration, and frequency of the exposure, be continuous, unobtrusive, valid, reliable and feasible. None of the existing methods satisfied all the criteria, therefore new methods must be developed, or those methods which came closest to fulfilling the criteria, might be adapted to suit the participants and the research setting.

Does Using a Chair Backrest or Reducing Seated Hip Flexion Influence Trunk Muscle Activity and Discomfort? A Systematic Review

OBJECTIVE

This paper systematically reviews the effect of chair backrests and reducing seated hip flexion on low back discomfort (LBD) and trunk muscle activation.

BACKGROUND

Prolonged sitting commonly exacerbates low back pain (LBP). Several modifications to seated posture and chair design have been recommended, including using chairs with backrests and chairs that reduce hip flexion.

METHOD

Electronic databases were searched by two independent assessors. Part 1 of this review includes 26 studies comparing the effect of sitting with at least two different hip angles. In Part 2, seven studies that compared the effect of sitting with and without a backrest were eligible. Study quality was assessed using the PEDro scale.

RESULTS

Significant confounding variables and a relatively small number of randomized controlled trials (RCTs) involving people with LBP complicates analysis of the results. There was moderate evidence that chair backrests reduce paraspinal muscle activation, and limited evidence that chair backrests reduce LBD. There was no evidence that chairs involving less hip flexion reduce LBP or LBD, or consistently alter trunk muscle activation. However, participants in several studies subjectively preferred the modified chairs involving less hip flexion.

CONCLUSION

The limited evidence to support the use of chairs involving less seated hip flexion, or the effect of a backrest, is consistent with the limited evidence that other isolated chair design features can reduce LBP.

APPLICATION

LBP management is likely to require consideration of several factors in addition to sitting position. Larger RCTs involving people with LBP are required.

Effect of Cognitive Load on Seating Posture in Children

Although children are frequently required to sit upright, it is often difficult to maintain this posture when performing cognitive tasks. Information about the relationship between a cognitive tasks and postural seating control is important for children to complete tasks more effectively. To determine the muscle activity and body sway of children in a seated posture while performing a cognitive task, changes in muscle activity and center of pressure (COP) were recorded while 4(th) grade children performed arithmetic tasks. Electromyography was recorded from the internal oblique and lumbar multifidus muscles, and the COP was recorded using a baropodometer placed on the stool. These variables were measured during easy (EA) and difficult (DA) arithmetic tasks. EMG activity decreased during the EA and DA tasks, while the COP was displaced in the DA task. The results of the arithmetic tasks were not related to the EMG or COP changes. Attention to maintain a seated posture may be reduced when children perform cognitive tasks. Therefore, it may be better to allow children to alter their posture especially when they are performing difficult tasks. In this research, we only used arithmetic tasks as the cognitive exercise, and therefore, other types of tasks should be examined.

Harnessing an Ergonomic Solution for Prolonged Sitting in Flight

Low-back pain is one of the consequences of sitting. Muscular fatigue leads to shifting from a straight posture into a slumped one. We believe that corrective supports to the pelvis and lumbar spine must be complemented with restraining shoulder straps to bypass muscle fatigue. This ergonomic design “formula” could potentially improve prolonged passive sitting conditions, such as on long-haul flights, in which most passengers sit in cramped surroundings. Our study’s results confirm this hypothesis. Further studies are required concerning cardiac and circulatory responses to the use of this device.

Evidence-based guidelines for the wise use of computers by children: physical development guidelines

Computer use by children is common and there is concern over the potential impact of this exposure on child physical development. Recently principles for child-specific evidence-based guidelines for wise use of computers have been published and these included one concerning the facilitation of appropriate physical development. This paper reviews the evidence and presents detailed guidelines for this principle. The guidelines include encouraging a mix of sedentary and whole body movement tasks, encouraging reasonable postures during computing tasks through workstation, chair, desk, display and input device selection and adjustment and special issues regarding notebook computer use and carriage, computing skills and responding to discomfort. The evidence limitations highlight opportunities for future research. The guidelines themselves can inform parents and teachers, equipment designers and suppliers and form the basis of content for teaching children the wise use of computers. STATEMENT OF RELEVANCE: Many children use computers and computer-use habits formed in childhood may track into adulthood. Therefore child-computer interaction needs to be carefully managed. These guidelines inform those responsible for children to assist in the wise use of computers.

Complaints arising from a mismatch between school furniture and anthropometric measurements of rural secondary school children during classwork

OBJECTIVES

The present investigation aimed to evaluate the extent of mismatch between different dimensions of school furniture and the respective anthropometric measures of school children. Assessment of health problems as well as postural pattern among the school children while attending their classes in relation to the classroom furniture was the other aim of this study.

METHODS

For this purpose, 621 male school children (age range 10-15 years) were selected at random from rural secondary schools (n = 20) in nine districts in the state of West Bengal, India. The subjective evaluation of health problems of the school children was made by questionnaire technique. Postural analysis of the children during classwork was made by video-photographic method as well as direct observation method. Anthropometric measures of the school children were taken by an anthropometer.

RESULTS

School children suffered from various discomforts/problems during classwork because of the school furniture. Anthropometric dimensions of the school children were found to increase with age, but most of the dimensions of the school furniture in different grades (V to X) remained more or less the same. The school children were found to change postures frequently while using such classroom furniture.

CONCLUSIONS

Mismatches between the dimensions of school furniture and body dimensions might be the reason for the occurrence of discomfort/problems in various parts of school children's bodies. It can be concluded that an ergonomic intervention is required to redesign the classroom furniture for school children of different age groups in order to reduce furniture-related health complaints.

Do ergonomically designed school workstations decrease musculoskeletal symptoms in children? A 26-month prospective follow-up study

Workstations at school are among several factors that contribute to musculoskeletal symptoms among school-aged children. The aim of this study was to investigate the effects of ergonomically designed workstations on schoolchildren's musculoskeletal symptoms as compared to conventional workstations. In the first 14-month phase of the study (2002-2003, two schools), 42 from the intervention and 46 from the control school participated. In the total follow-up of 26 months (2002-2004), 23 in the intervention group and 20 in the control group participated. Anthropometrics and musculoskeletal symptoms were measured. In general, the ergonomically designed school workstations did not decrease present neck-shoulder, upper back, low back and lower limbs strain and pain, compared to conventional ones during follow-ups.

Survey of faulty postures and associated factors among Chinese adolescents

OBJECTIVE

This study investigates the prevalence of common faulty postures among adolescents and identify if significant relationships existed among the number of faulty postures, psychologic distress, and musculoskeletal symptoms.

METHODS

The Musculoskeletal Questionnaire and Chinese Health Questionnaire were randomly distributed to 300 high school students in the Tainan area. On-campus postural screening, which included digital photography, manual muscle tests, and flexibility tests, was also performed.

RESULTS

Two hundred eighty-seven participants completed all of the evaluations. The most common faulty posture was uneven shoulder level (36%), followed by forward head posture (25%). There was a sex difference between groups. The incidence of forward head posture for the male students was higher than that of the female students (P < .0001). In addition, the high psychologic distress group tended to have a higher prevalence of uneven shoulder height than that of the low psychologic distress group (P < .0001). As for the correlation analysis, the researchers did not find a high correlation among the scores of the faulty posture, psychologic distress, and musculoskeletal symptoms.

CONCLUSION

The results of this study show that the incidence of faulty posture was high for the adolescent group, especially for the uneven shoulder level. Subjects' awareness about being assessed might decrease the incidence for some faulty posture. However, the relationships among the number of faulty postures, psychologic distress, and musculoskeletal symptoms were low. We suggest that there are multiple factors that might contribute to musculoskeletal symptoms; faulty posture could be one important factor that causes symptoms.

Children have less variable postures and muscle activities when using new electronic information technology compared with old paper-based information technology

Children now have considerable exposure to new information technologies (IT) such as desktop computers. A reported association between computer use and discomfort in children has prompted concerns about the musculoskeletal stresses associated with computer use. There were no detailed data on children reading and writing, nor any evidence on the variability of postures and muscle activity whilst children use IT. Twenty-four children (10-12 years old; 12 male) performed a reading and writing task using new IT (computer/keyboard/mouse with high display and mid height display) and old IT (book/paper/pen). Spinal and upper limb 3D posture and muscle activity were recorded and estimates of mean and variation calculated. The mean postures for children reading and writing with computers were more neutral than when they read and wrote with old IT. Similarly, mean muscle activity levels were lower during computer use than old IT use. However, new IT use also resulted in less variable, more monotonous postures and muscle activities. Moderate differences in computer display height had little effect on posture and muscle activity variation. Variation in musculoskeletal stresses is considered an important component of the risk of musculoskeletal disorders. Children should therefore be encouraged to ensure task variety when using new IT to offset the greater posture and muscle activity monotony.

A cross-sectional study of self-reported back and neck pain among English schoolchildren and associated physical and psychological risk factors

This study set out to identify the associations between ergonomics and other factors with back and neck pain among schoolchildren. Self-reported questionnaires were used to record health outcomes and potential risk factors in state schools. Six hundred and seventy-nine schoolchildren from Surrey in the United Kingdom aged 11-14 years took part. Twenty-seven percent of children reported having neck pain, 18% reported having upper back pain, and 22% reported having low back pain. A forward stepwise logistic regression was performed with pain categories the dependent variables. Neck pain was significantly associated with school furniture features, emotional and conduct problems, family history of low back pain and previous treatment for musculoskeletal disorders. Upper back pain was associated with school bag weight (3.4-4.45 kg), school furniture features, emotional problems and previous treatment for musculoskeletal disorders. Low back pain was associated with school furniture features, emotional problems, family history and previous injury or accident. It is important to recognise the influence of physical, psychological and family factors in children's pain.

Classroom postures of 8-12 year old children

This study examined classroom postures of 8-12 year old school children in Flanders and related the outcomes to self-reported back or neck pain. Postural behaviours using the portable ergonomic observation (PEO) method and self-reported one-week back and neck pain were studied in 105 children from 41 different class groups. Pupils sat statically for 85% of the time, 28% of which the trunk was bent or flexed forward. For 9% of the time, children sat dynamically and for 36% they used a back rest. Children who spent more time sitting with a flexed trunk reported significantly more thoraco-lumbar pain compared to pain-free children and to children with cervical pain (p < 0.05). Children reporting pain stood for a longer period of time than pain-free children (p < 0.05). It is concluded that prolonged static kyphotic sitting without use of a backrest is common in elementary school children in Flanders.

Are the desks and chairs at school appropriate?

The aim of the current study was to find out how the measures of chairs and desks match with the anthropometrics of schoolchildren and how schoolchildren sit during a lesson in their classroom. This paper reports the baseline measurements of an intervention study. Participants of this study were 6th and 8th grade (12 and 14 year old) schoolchildren from two comprehensive schools in Finland (N = 101, 57 girls and 44 boys). The main outcome measures were the differences between desk height and elbow-floor height, and chair height and popliteal height. Forty-three participants were randomized for sitting posture analysis by video recordings. The study showed that desks were on average 13 cm above elbow-floor height and chairs 2 cm below popliteal height. For 56% of time participants sat with their backs flexed >20 degrees and/or rotated >45 degrees . For 70% of time they sat with their necks flexed >20 degrees or rotated >45 degrees. The results indicate that there is a mismatch between school furniture and the anthropometrics of schoolchildren. Schoolchildren sit in disadvantaged postures for a substantial part of school lessons.

The working postures among schoolchildren--a controlled intervention study on the effects of newly designed workstations

BACKGROUND

School workstations are often inappropriate in not offering an optimal sitting posture. The aim of this study was to investigate the effects of individually adjustable saddle-type chairs with wheels and desks with comfort curve and arm support on schoolchildren's working postures compared to conventional workstations.

METHODS

Ninety-seven participants aged 12-16 years were followed for 1 year, 47 at an intervention school and 50 at a control school. Anthropometrics and workstation dimensions were measured and working postures analyzed for a part of each group (n = 21, both groups) by means of video recording at baseline, before new workstations were introduced, and during follow-up.

RESULTS

There was a significant increase in upright back (p= .012) and neck (p= .019) postures in the intervention group compared to controls during follow-up. The saddle-type chairs allowed significantly greater trunk-thigh angles (p < .001) among participants than conventional chairs.

CONCLUSIONS

In schoolchildren, using individually adjustable saddle-type chairs and desks with comfort curve, a better match between workstations and anthropometric dimensions and improved working postures are obtained than using conventional workstations.

Postural development in school children: a cross-sectional study

Background

Little information on quantitative sagittal plane postural alignment and evolution in children exists. The objectives of this study are to document the evolution of upright, static, sagittal posture in children and to identify possible critical phases of postural evolution (maturation).

Methods

A total of 1084 children (aged 4–12 years) received a sagittal postural evaluation with the Biotonix postural analysis system. Data were retrieved from the Biotonix internet database. Children were stratified and analyzed by years of age with n = 36 in the youngest age group (4 years) and n = 184 in the oldest age group (12 years). Children were analyzed in the neutral upright posture. Variables measured were sagittal translation distances in millimeters of: the knee relative to the tarsal joint, pelvis relative to the tarsal joint, shoulder relative to the tarsal joint, and head relative to the tarsal joint. A two-way factorial ANOVA was used to test for age and gender effects on posture, while polynomial trend analyses were used to test for increased postural displacements with years of age.

Results

Two-way ANOVA yielded a significant main effect of age for all 4 sagittal postural variables and gender for all variables except head translation. No age × gender interaction was found. Polynomial trend analyses showed a significant linear association between child age and all four postural variables: anterior head translation (p < 0.001), anterior shoulder translation (p < 0.001), anterior pelvic translation (p < 0.001), anterior knee translation (p < 0.001). Between the ages of 11 and 12 years, for anterior knee translation, T-test post hoc analysis revealed only one significant rough break in the continuity of the age related trend.

Conclusion

A significant linear trend for increasing sagittal plane postural translations of the head, thorax, pelvis, and knee was found as children age from 4 years to 12 years. These postural translations provide preliminary normative data for the alignment of a child's sagittal plane posture.

Human factors engineering and patient safety

The pediatric population has features different from those of adults and that are dynamic during the pediatric age range. Pediatric-specific issues result in potential risks for harm during medical care. Basic and applied human factors research has resulted in improvements in the performance of health adults and those adults who have functional limitations. Future work should focus on systematically understanding the human factors needs of children with the goal of redesigning systems of health care to optimize the safety of children and the performance of their care providers.

Back pain in school children--where to from here?

Back pain is now recognised to occur early in childhood and is associated with high prevalence rates when estimated by survey. This review paper considers the risk factors associated with back pain in children aged 11-14 years, and particularly those present in a school setting. The risk factors most significantly associated with back pain are primarily characteristics of the individual with less strong associations with factors present in the school environment. The majority of intervention studies undertaken in a school setting have focussed on the effect of school furniture on posture and comfort and were of short-term duration. There is a need for further research in order to achieve a better understanding of the risk factors present in a school environment and to address ways to reduce the currently recognised perceived problem of back pain among school children. A strategy for an evidence-based longitudinal intervention study is proposed, with the content outlined under the headings: policy, school equipment and furniture, individual and family.

Sitting habits in elementary schoolchildren: a traditional versus a "Moving school"

This study evaluated differences in sitting habits in the classroom between the project "Moving school" and a traditional school in 8-year-old children. Twenty-two children, since 1.5 years involved in the project were compared to 25 children in a traditional school. Making use of the Portable Ergonomic Observation (PEO) method, it was observed that children from a traditional school spend an average of 97% of the lesson time sitting statically, from which one-third with the trunk bend over 45 degrees. In the "Moving school" this posture was replaced by dynamic sitting (53%), standing (31%) and walking around (10%), while trunk flexion over 45 degrees was nearly not observed. Children from the "Moving school" also showed significantly less neck and trunk rotation. Additionally, accelerometric data showed significantly more physical activity in lessons of the "Moving school". Rates of self-reported back or neck pain did not differ significantly between both study groups. Results show that sitting habits are more favourable in a "Moving school". Further research is needed to study the impact of implementing "Moving school" concepts in traditional schools on sitting habits.

Classroom furniture dimensions and anthropometric measures in primary school

The purpose of this study was to compare students' dimensions to the dimension of school furniture, in primary school, and determine whether this type of furniture is well-designed and promotes good sitting posture at school by taking into account the dimensions of the children. A total of 180 (90 male and 90 female) students, from three primary schools in Thessaloniki, Greece, participated in the study. Their ages ranged from 7 to 12 years. The following human body dimensions were measured: stature, elbow height, shoulder height, upper arm length, knee height, popliteal height and buttock-popliteal length. In addition, the dimensions were measured for four different types of chairs and five types of desks prevalent in classrooms. Finally, the anthropometric measures of the students and the furniture dimensions were compared in order to identify any incompatibility between them. The data indicate a mismatch between the students' bodily dimensions and the classroom furniture available to them. The chairs are too high and too deep and desks are also too high for the pupils. This situation has negative effects on the sitting posture of the children especially when reading and writing.

Classroom posture and self-reported back and neck pain in schoolchildren

The study reported here aims to identify the extent of back pain experienced by 11-14 year old schoolchildren, and establish the intensity, duration and frequency of exposure to physical risk factors present in schools. This paper considers the sitting postures of schoolchildren in the classroom. The sitting postures of 66 children were recorded in normal lessons using the Portable Ergonomic Observation Method (PEO). The study found significant associations between flexed postures and low back pain. Static postures and neck and upper back pain were also associated. This study has implications for schools, designers and people in the field of work related musculoskeletal disorders. Further research is required to examine the association between sitting posture and pain reported at different spinal locations.

Comparing the effect of different design of desks with regard to motor accuracy in writing performance of students with cerebral palsy

This study was conducted to examine the effect of ergonomic desk design for improving motor accuracy in the writing performance of cerebral palsy students. Thirty-two cerebral palsy students were tested in four workstations. The test order was randomized. Work surface design involved a regular work surface and a cutout work surface, and desk angle design included a horizontal desk top and a 20 degrees inclined desktop. The height of the desk and chair were adjusted relatively to each subject's height and popliteal height. Writing performance while using the four workstations were compared by administering the Motor Accuracy Test. Motor writing accuracy adjusted for speed was significantly better at the cutout work surface than at the regular work surface. Students with athetoid quadriplegia benefited more from the cutout surface. Although the inclined desktop was more appropriate for better vision and less neck flexion, there were no differences in accuracy scores and adjusted scores between the horizontal desk and the inclined desk. These findings support the hypothesis that the cutout work surface, which was accommodated to the anterior trunk, facilitates trunk control and provides forearm support in addition to improving writing performance.

Differences in postural control and movement performance during goal directed reaching in children with developmental coordination disorder

Poor upper-limb coordination is a common difficulty for children with developmental coordination disorder (DCD). One hypothesis is that deviant muscle timing in proximal muscle groups results in poor postural and movement control. The relationship between muscle timing, arm motion and children's upper-limb coordination deficits has not previously been studied. The aim of this study was to investigate the relationship between functional difficulties with upper-limb motor skills and neuromuscular components of postural stability and coordination. Sixty-four children aged 8-10 years, 32 with DCD and 32 without DCD, participated in the study. The study investigated timing of muscle activity and resultant arm movement during a rapid, voluntary, goal-directed arm movement. Results showed that compared to children without DCD, children with DCD took significantly longer to respond to visual signals and longer to complete the goal-directed movement. Children with DCD also demonstrated altered activity in postural muscles. In particular, shoulder muscles, except for serratus anterior, and posterior trunk muscles demonstrated early activation. Further, anterior trunk muscles demonstrated delayed activation. In children with DCD, anticipatory function was not present in three of the four anterior trunk muscles. These differences support the hypothesis that in children with DCD, altered postural muscle activity may contribute to poor proximal stability and consequently poor arm movement control when performing goal-directed movement. These results have educational and functional implications for children at school and during activities of daily living and leisure activities and for clinicians assessing and treating children with DCD.

Evaluation of a prototype multi-posture office chair

Office chairs have often been designed to promote a single 'correct' rather rigid and upright posture, yet it is acknowledged that allowing changes in posture is good ergonomics practice. The present study investigated office worker's preferences for a standard shaped typist's chair (ST) and a prototype multi-posture (PMP) office chair designed to allow its users a variety of sitting positions. Forty-two (22 male and 20 female) telesales personnel (12), clerical staff (12) and researchers (18) used ST or PMP in their workplace for the first week of a 2-week study (with an even number in each work area). The PMP chair was introduced to participants with a brief lecture on how to use it and with an information booklet. Following this, each participant completed a chair comfort questionnaire. In the second week, participants swapped chairs and again completed the chair comfort questionnaire. At the end of the second week participants were also asked to complete a separate questionnaire about the usability of the information booklet that accompanied the PMP chair. Statistically significant differences in subject's rating of the two chairs were observed in 7 out of 19 questions. On a 100 mm scale, the ST chair was rated as having a greater mean overall acceptability, desirability and suitability for body build than the PMP chair. Participants also claimed to achieve better posture in the ST chair, that they tipped forward less and were more satisfied with its width. Although the participants generally preferred the ST chair, the PMP chair received more favourable ratings among the researchers who were quite mobile in their work, and in whom there was a trend for less neck, shoulder and upper back discomfort. More participants reported an overall preference for the PMP chair. The findings suggest that a more aesthetically acceptable PMP chair should be developed, peoples' reasons for preferring a more traditionally designed chair should be explored, and that the effect of postural stability education on personal preconceptions should be examined to obtain an optimal combination of healthy sitting habits, comfort and aesthetic qualities in an office chair.

Children's behaviour and the design of school furniture

Children spend a large part of their school days in the classroom, and yet the effect of the design of school furniture on their behaviour and health has received comparatively little attention in the UK. An experimental study is reported that compares the effects on children's behaviour and sitting position of traditional classroom furniture with a recently designed chair known as 'Chair 2000' and associated tables. It was found that children showed a modest but significant improvement in on-task behaviour and a marked change in sitting positions following the introduction of the newly-designed furniture. However, these benefits need to be considered in the light of polarized opinion for and against the new furniture, and a high level of reported incidence of back pain significantly related to the frequency of non-standard sitting. In the absence of radically redesigned furniture, it is suggested that children should be given more choice in their seating, and better guidance should be given to individuals involved in education in order to inform their decision-making about classroom furniture and the postural, anthropometric and orthopaedic aspects of sitting and related activities.