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Unlabelled: Children's computer exposure is rapidly growing. Several studies have suggested children using computers may be at risk of developing musculoskeletal symptoms. General models and theories relating to the causality of negative musculoskeletal outcomes in adult workers demonstrated relationships between workplace factors and musculoskeletal outcomes. When examining children's computer exposure it is evident that their use is different. Even though risk factors may be similar, due to the nature of children and their computer environments, the potential risk factors and thus a proposed model of causal relationships between exposure and outcomes may differ., Objective: To develop a model of factors influencing computer exposure and musculoskeletal symptoms in children., Methods: 1351 children (or their parents for Year 1 children) in school Years 1, 6, 9 and 11 (ages ~ 6,11,14,16 years) from 10 schools in Western Australia were surveyed on a range of user characteristics, computer exposure and musculoskeletal symptoms., Results: Potential risk factors for childrens' computer exposure and musculoskeletal outcomes were multivariable. Factors such as age, gender, somatic complaints, flow, computer anxiety, computer, TV and physical activity exposure, and SES were related to computer exposure and children's reports of musculoskeletal symptoms., Significance: Developing a child-related computer exposure model to understand relationships between potential risk factors and musculoskeletal symptoms will assist academics, teachers and parents to develop a better understanding of the risk factors for children's computer exposure.

Background: Computer use is associated with musculoskeletal complaints among office workers. Insufficient exposure diversity between tasks is a proposed etiological factor, but little information exists on diversity of tasks and information and communication technologies (ICT) among office workers., Method: Direct observation and self-report data were collected on tasks performed and ICT used among 24 office workers, over 12 h in work and non-work environments. Self-reports were repeated on four additional days., Results: Observations were for a mean [SD] 642[40] min. Productive tasks comprised 63% of observations, instrumental 17%, self-care 12% and leisure 8%. Non-ICT tasks comprised 44% of observations; New electronic-based ICT 36%; Old paper-based ICT 15%, and Combined ICT tasks 4%. Proportions of tasks and ICT use differed between environments and days., Conclusion: Information about diversity in tasks and ICT provides the basis for future investigations into exposure variation in ICT-intensive environments and possible musculoskeletal health risks. STATEMENT OF RELEVANCE: Information and communication technologies (ICT) provide office workers access to perform work-related tasks after work hours and in away-from-work locations. Musculoskeletal disorder risk assessment for office workers should account for actual tasks performed over a work day, including away from work exposures. This study provides rich, detailed data on occurrence of tasks performed and ICT used by office workers throughout the day.

Purpose: Playing-related musculoskeletal problems (PRMP) are common in adult musicians, and risk factors include gender, music exposure, and particularly instrument type. Emerging evidence suggests PRMP are common in children and adolescents and that risk factors may be similar. The aim of this study was to determine the prevalence of PRMP, both symptoms and disorders, and PRMP location in children and adolescents as well as the associations with gender, age, and music exposure factors such as type and number of instruments and playing time., Methods: This study surveyed 731 children (460 females), aged 7 to 17 years, studying instrumental music in government schools in Perth, Australia. Lifetime and monthly symptoms, monthly disorders (inability to play an instrument as usual), and PRMP location were examined. Chi-squared analyses were used to evaluate associations between gender, age, music exposure, and PRMP outcomes. Logistic regression evaluated the independent association of these potential risk factors with PRMP prevalence and location. RESULTS) Sixty-seven percent of students reported PRMP symptoms at some point, 56% reported them within the last month, and 30% reported an inability to play as usual within the last month. After adjustment for gender and age, the type of instrument played (upper and lower strings, woodwind, and brass) was significantly associated with all PRMP (p<0.005) and playing three instruments was protective against monthly symptoms (OR 0.43, p=0.05). The right (24%) and left (23%) hand/elbow and neck (16%) were the most commonly reported PRMP locations, with females affected significantly more than males Prevalence of PRMP increased with age for neck (p<0.001), mid-back (p=0.007), low back (p<0.001), right hand/elbow (p=0.008), and mouth (p=0.011). PRMP prevalence for the left hand/elbow and right and left shoulders demonstrated high rates across all childhood ages. Odds ratios for the risk of PRMP in different locations varied by instrument played., Conclusions: The high prevalence and location of PRMP are important issues for child and adolescent instrumentalists. Gender, age, and music exposure are associated with PRMP risk and need to be addressed to ensure musicians' personal well-being and musical longevity.

A cross-sectional study of 1258, 14 year old girls and boys used self-report and physical examination measures to assess neck/shoulder pain in the last month, depressed mood, physical fitness, body composition, self-efficacy, global self-worth, family functioning and social advantage. The data was used to compare the relationship between depressed mood and neck/shoulder pain (NSP) in adolescent girls and boys. The prevalence of NSP in girls (34%, 211/621) was significantly greater than in boys (21%, 134/637; p < .001). After controlling for covariates, girls with medium (OR = 4.28; CI = 2.31-7.92; p < .001) and high depressed mood (OR = 8.63; CI = 4.39-16.98; p < .001) were significantly more likely to report NSP than girls with low depressed mood. Depressed mood was also a significant correlate of NSP in boys after controlling for covariates, although the association was substantially weaker (OR = 2.44; CI = 1.29-4.61; p < .001). After controlling for relevant biological, psychological and social covariates, depressed mood was a significant correlate of NSP in both sexes; but the association between depressed mood and NSP was significantly stronger for girls than for boys., (Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.)

The aims of this study were to determine differences between swimmers/non-swimmers, males/females and dominant/non-dominant sides for scapular and humeral head position, while accounting for size, and to determine the relationship between scapular and humeral head position. 46 teenage swimmers (30 females) and 43 non-swimmers (28 females) were measured. The distances between (a) medial spine of the scapula and T3/4 (Superior Kibler), (b) inferior scapula and T7/8 (Inferior Kibler) and (c) anterior acromion and anterior humeral head were recorded while teenagers stood with their hands-on hips. There was no main effect difference between swimmers and non-swimmers for scapular or humeral head position. There were interactions for swim status/dominance (Superior Kibler; P=0.005, Inferior Kibler; P<0.001) and swim status/gender (Superior Kibler; P=0.027). The humeral head was significantly further from the acromion on the dominant side (adjusted mean difference=1.4 mm, P=0.004). Little relationship between scapular and humeral head position was evident. Clinicians should be aware that swim status, in combination with gender or dominance may affect scapular position but does not affect humeral head position. Where swimming had an effect, it minimized differences between genders and sides. The small dominance effect on the humeral head position is unlikely to be clinically detectable., (© 2009 John Wiley & Sons A/S.)

Objective: School children use information and communication technology (ICT) on a regular basis for a variety of purposes. The purpose of this study was to document how school children spend their time and the different types of ICT they use., Methods: Nine Australian primary school children were observed in their school and away-from-school environments during one school day to record their ICT usage, comparing self-report exposures with direct observations. Self-reported discomfort scores were obtained throughout the day., Results: Paper-based ICT (Old ICT) was mostly used for productive occupations at school, while electronic-based ICT (New ICT) was mostly used during leisure in away-from-school locations. Tasks involving no ICT (Non-ICT) accounted for the largest proportion of time in both locations during self-care, leisure and instrumental occupations. End-of-day self-reported time performing different occupations was consistent with data from independent observations. Self reported time using Old ICT and New ICT was marginally over-estimated, and time spent using Non-ICT was marginally under-estimated., Conclusion: The children in this study used a variety of ICT in the performance of daily occupations in their natural environments. New ICT use was primarily for leisure, but time spent was less than reported in other studies. Discomfort reports among the participants were low. Participants' self-reports of occupations performed and ICT use was reliable and could be useful as an exposure assessment metric.

Objective: There are concerns that insufficient variation in postural and muscle activity associated with use of modern information and communication technology (ICT) presents a risk for musculoskeletal ill-health among school children. However, scientific knowledge on physical exposure variation in this group is limited. The purpose of this study was to quantify postures and muscle activity of school children using different types of ICT., Method: Postures of the head, upper back and upper arm, and muscle activity of the right and left upper trapezius and right forearm extensors were measured over 10-12 hours in nine school children using different types of ICT at school and away-from-school. Variation in postures and muscle activity was quantified using two indices, EVA{sd} and APDF₉₀-₁₀., Results: Paper-based (Old) ICT tasks produced postures that were less neutral but more variable than electronics-based (New ICT) and Non-ICT tasks. Non-ICT tasks involved mean postures similar to New ICT tasks, but with greater variation. Variation of muscle activity was similar between ICT types in the right and left upper trapezius muscles. Non-ICT tasks produced more muscle activity variation in the right forearm extensor group compared to New and Old ICT tasks., Conclusion: Different ICT tasks produce different degrees of variation in posture and muscle activity. Combining tasks that use different ICT may increase overall exposure variation. More research is needed to determine what degree of postural and muscle activity variation is associated with reduced risk of musculoskeletal ill-health.

Study Design: Cross-sectional investigation., Background: There is some evidence that interventions directed to improving back muscle endurance (BME) in adolescents are effective in reducing low back pain, with anecdotal evidence of improved performance. However, the mechanisms responsible for this improvement remain unclear., Objective: To identify the relationship between physical, lifestyle, and psychological variables and BME in a large adolescent population, while controlling for back pain and gender., Methods: One thousand four-hundred thirty-five adolescents (702 females, 733 males; mean +/- SD age, 14.0 +/- 0.2 years) completed a range of physical, lifestyle, and psychological assessments. The group mean +/- SD height and body mass were 164 +/- 8 cm and 57.1 +/- 12.6 kg, respectively. Linear regression was used to investigate the univariate association between each of the physical, lifestyle, and psychological variables and BME. Backwards stepwise multivariate linear regression was used to determine statistically significant independent correlates of BME., Results: The final multivariate model explained 15.3% of the variance in BME and included at least 1 variable from the physical, lifestyle, and psychological domains. Adolescents who exercised less, watched more television, had a higher body mass index, sat in a more flexed trunk posture (more slumped), and had lower self-efficacy had lower BME., Conclusions: All the physical and lifestyle variables linked with poorer BME performance in this investigation are indicative of reduced back muscle activation and/or deconditioning. Psychological predictors may have direct and/or indirect links with BME.

Posture and movement are thought to be important risk factors for the development of work-related musculoskeletal disorders. Whole day occupational exposure assessment has typically used self-report or observation techniques, but the need for more accurate measurement is now recognised. The aim of this study was to compare the kinematic recordings of a frequently used field system (physiometer) with two laboratory-based systems (Fastrak and Peak) in vivo. Head, thorax and right arm kinematics were recorded simultaneously by the three systems whilst a subject performed 27 single and multiple plane physiological and simulated daily living task movement trials. Errors observed in the Fastrak and Peak data included gimbal lock and quadrant errors. Physiometer data errors included undervalues, overvalues and temporal errors of slow response and resonance. All three systems showed some cross-talk. Agreement between the physiometer and the other systems was generally high for physiological movements (R(2) > 0.8) and less for functional movements (R(2) > 0.5). STATEMENT OF RELEVANCE: The physiometer recording device can provide an indication of posture across time in the workplace; however, its accuracy is limited, particularly during functional movements. Further technology should be developed to unobtrusively capture accurate all day 3-D kinematics.

Objective: In this study, the amplitude and time distribution of power output in a variety of competitive cycling events through the use of a new mathematical analysis was examined: exposure variation analysis (EVA)., Design: Descriptive field study., Setting: Various professional road cycling events, including; a 5-day-eight-stage tour race, a 1-day World Cup event and the Australian National Individual Time Trial Championships., Participants: 9 elite female cyclists (mean (SD), mass = 57.8 (3.4) kg, height = 167.3 (2.8) cm, Vo(2)peak = 63.2 (5.2) ml kg(-1) min(-1))., Interventions: None., Main Outcome Measurements: The variation in power output and the quantification of the total time and acute time spent at various exercise intensities during competitive professional cycling were examined. Predefined levels of exercise intensity that elicited first ventilation threshold, second ventilation threshold and maximal aerobic power were determined from a graded exercise test performed before the events and compared with power output during each event., Results: EVA exposed that power output during the time trial was highly variable (EVA(SD) = 2.81 (0.33)) but more evenly distributed than the circuit/criterium (4.23 (0.31)) and road race events (4.81 (0.96))., Conclusion: EVA may be useful for illustrating variations in the amplitude and time distribution of power output during cycling events. The specific race format influenced not only the overall time spent in various power bands, but also the acute time spent at these exercise intensities.

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.

Objective: This study aimed to determine the effects of active workstation designs on speed and error during typing, mouse pointing, and combined type and mouse-use tasks., Background: Office ergonomics has focused on musculoskeletal disorder prevention; however, increasing computer-based work also increases health risks associated with inactivity. Workstations allowing computer users to walk or cycle while performing computer tasks have been shown to demand sufficient energy expenditure to result in significant health benefits. However the performance effects of being active while using a computer have not been documented., Method: Thirty office workers (16 female, 15 touch typists) performed standardized computer tasks in six workstation conditions: sitting, standing, walking at 1.6 km/h and 3.2 km/h, and cycling at 5 and 30 watts. Performance, perceived performance, and heart rate were measured., Results: Computer task performance was lower when walking and slightly lower when cycling, compared with chair sitting. Standing performance was not different from sitting performance. Mouse performance was more affected than typing performance. Performance decrements were equal for females and males and for touch typists and nontouch typists., Conclusion: Performance decrements maybe related to both biomechanical and cognitive processes. Active workstations may be less suitable for mouse-intensive work and susceptible users., Application: Although active workstations may result in some decrement in performance, their ability to increase daily energy expenditure may make them a feasible solution for workplace inactivity.

Physical activity, physical fitness and motor competence are important health-related constructs. However, the relationship among them, particularly for children and adolescents, is still unclear. In this study, motor competence (measured by the McCarron Assessment of Neuromuscular Development), pedometer-determined physical activity and physical fitness (aerobic fitness, muscle strength, muscle endurance, flexibility and body composition) were examined in a cohort of 1585 adolescents (771 girls, 814 boys) of mean age 14.06 years. Significant gender differences were observed for all measures except motor competence. Apart from hip and shoulder flexibility, males outperformed females. For both males and females, motor competence was associated with all fitness measures, physical activity was associated only with aerobic fitness and aerobic fitness was associated with physical activity, motor competence, BMI and chest pass. Among males, aerobic fitness was also associated with all other fitness tests. The correlations were, in general, moderate to weak. The results challenge the current focus on physical activity rather than physical fitness as the preferred intervention.

Desk design and computer display height can affect posture and muscle activation during computer use. Amplitudes of postural variables and muscle activity during computer use do not explain the results from epidemiological studies of musculoskeletal discomfort and disorders related to computer use. The purpose of this study was to assess variability of posture and muscle activity during work with two computer display heights and book/paper, in conjunction with a curved desk designed to provide forearm support and a traditional, straight desk. 18 male and 18 female participants performed 10-min tasks involving keying, mousing, reading and writing in six desk/display conditions. 3D posture and surface emg were assessed for the final 2 min of each task. The curved desk resulted in greater postural and muscle activity variation, suggesting an advantage of this supportive surface over the straight desk. There was little difference in variability associated with the two display heights. However, greater variability of posture and muscle activity was evident with the book/paper condition. Non-touch typists had greater neck flexion variation. The design of information technology tasks and workstations can influence the short term variation in posture and muscle activity. Variation is influenced independently of mean postures and muscle amplitudes and therefore needs to be considered to adequately assess the risk of musculoskeletal disorders.

The purpose of this study was to determine the degree of criterion validity and intra-tester reliability of humeral head palpation in subjects with shoulder pathology. The study also sought to determine whether there was any effect of arm position on humeral head position in subjects with shoulder pathology. In a same day repeated measures design, 27 subjects had the distance between the most anterior portion of the humeral head and the anterior edge of the acromion measured by a radiologist using MRI (supine), and by a physiotherapist using palpation and photography (supine, sit with arm in neutral and in abduction). The Standard Error of Measurement (SEM) for the difference between MRI and palpation ranged from 3.4 to 4.4mm and correlated significantly with palpation measures in sit (r=0.57-0.64, p

Objectives: To determine the inter-tester reliability of a clinical measure of humeral head position., Design: Same day repeated measures inter-tester reliability study., Setting: 2 Western Australian Aquatic Centres., Participants: 15 Junior elite swimmers were measured by 3 investigators., Main Outcome Measures: The distance between the most anterior part of the humeral head and the anterior acromion was measured with shoulder in neutral position and hands on hips position., Results: The humeral head SEMs ranged from 2.4 to 3.2 mm. ICCs were 0.60-0.68 in the hands on hips position and 0.49 in the neutral position. Significant differences existed between testers for some humeral head measures., Conclusions: Humeral head in the hands on hips position measure appears to be a clinically useful tool in assessment of the shoulder in young athletes.

Bone health is generally not considered in patients who present with chronic back pain. Nonetheless, bone health and back pain share common genetic and environmental correlates suggesting a co-dependence. Evidence exists for a relationship between back pain and impaired bone health. Here we present the evidence, theoretic framework and clinical relevance. Bone health and back pain are important determinants of musculoskeletal health. Back pain experienced in youth is a risk factor for future back pain, while suboptimal bone health during development increases the risk of skeletal fragility in later life. Generally, bone health is not considered in patients with chronic back pain who do not demonstrate other well-recognised bone health risk factors or associated conditions. Nonetheless, evidence suggests that back pain and impaired bone health share common environmental and genetic correlates, indicating that bone health ought to be considered in the context of back pain in otherwise healthy individuals. This review describes the likely mechanisms explaining the relationship between back pain and impaired bone health, evidence concerning the relationship and suggestions for future research. A narrative literature search was conducted using CINAHL, Medline, PubMed and Web of Science electronic databases. A history of back pain is associated with decreased bone mineral density in adults, yet this tends to be site-specific. No studies were identified examining this association in youth, yet the negative effects of childhood skeletal trauma and obesity on bone and spinal health provide indirect evidence for an association. Further research is required to clarify the impact of back pain on bone health at different lifespan stages using prospective cohort designs.

Head and neck posture is an important factor in neck pain related to computer use; however, the evidence for an optimal posture is unconvincing. This study measured the 3-D postures of 36 young adults during use of three different display heights. Cervical extensor muscle strain was estimated using modelled gravitational load moments and muscle capacities. The influence of more or less upper vs. lower cervical movement was also explored across a broad range of potential postures. Overall cervical extensor muscle capacity diminished away from a neutral posture whilst gravity moment increased with flexion. Overall cervical extensor muscle strain increased with head flexion but remained stable into head extension. Individual differences in the amount of upper and lower cervical movement had an important effect on strain, particularly for some muscles. Computer display height guidelines are an important component of ergonomics practice, yet the relative strain on neck extensor muscles as a function of display height has not been examined. The current findings provide more detailed biomechanical evidence that ergonomists can incorporate with usability and other evidence to determine appropriate display height recommendations.

Children commonly report musculoskeletal discomfort related to different activities such as computer use, playing electronic games, watching TV, reading, and performing physical and hand intensive activities. Discomfort can result in disability and is a strong predictor of future discomfort in adulthood. Adult beliefs regarding discomfort can affect the level of disability and are modifiable. Children's beliefs regarding discomfort could potentially be modified to minimise disability related to musculoskeletal disorders. The aim of this study was to describe children's beliefs about why they experience musculoskeletal discomfort, both in general and related to specific activities. Eighty eight school children completed questionnaires on frequency and usual duration of nine activities, whether they had felt discomfort and what they believed was the cause of any discomfort in relation to those activities. The most common activity was TV watching, and most activities were performed for 1 hour or shorter. Bad posture and doing too much of a certain activity were the most common beliefs regarding reasons for discomfort. This study shows that children are developing beliefs that tend to reflect scientific knowledge about risk factors. These beliefs could be incorporated into preventative health interventions.

Children and young adults are the most frequent users of computers. Whilst guidelines for adults have been based on research, available guidelines for children have had to assume children and adults are similar due to limited research evidence derived specifically from children. This study aimed to compare the posture and muscle activity of children with young adults. Thirty six adults aged 18-25 years, 24 children aged 10-12 years and 18 children aged 5-6 years participated in a series of laboratory studies. Upper body postures were measured using a 3D motion analysis system. Muscle activity of bilateral cervical erector spinae and upper trapezius muscles was assessed. Mean and variation were examined, the latter using both amplitude range and Exposure Variation Analysis matrix standard deviation. Mean postures assumed by children tended to show more spinal flexion and spinal asymmetry than adults. However children also tended to show more variation in posture and muscle activity. These findings suggest that whilst there may be differences in how children and adults use computers, basic principles of encouraging appropriate postures and variation should apply for both children and adults.

Background: Nurses are known to be a high risk group for occupational low back pain (LBP). The periods of greatest risk for developing low back pain in this population are not well defined. Recent literature suggests current preventative strategies are not consistently effective in improving low back injury statistics among health care populations., Objectives: To identify the relative contributions of age and occupational exposure on the prevalence, duration and severity of low back pain episodes among undergraduate nursing students and recently graduated nurses., Design: Cross-sectional survey., Settings: Two university undergraduate nursing schools and one public teaching hospital graduate nurse training program in Western Australia., Participants: 897 undergraduate nursing students (years 1, 2 and 3) and 111 graduate nurses recruited by personal invitation during lectures., Methods: Using a modified version of the Nordic Low Back Questionnaire, information regarding low back pain episode prevalence, impact, duration, frequency and causes was obtained., Results: Mean age was consistent across all groups (26.7+/-9.0 years) and had no significant effect on lifetime low back pain prevalence (p=0.30). Very high lifetime (79%), 12 month (71%) and 7 day (31%) low back pain prevalence rates were consistent across all 3 year groups of undergraduate nursing students, but were significantly higher after 12 months of full-time employment [lifetime (95.5%), 12 month (90%) and 7 day (39%)]. Around 60% of all respondents with low back pain utilised at least one of (a) treatment, (b) medication, or (c) a reduction in activity. Nursing students and graduate nurses attributed the majority of their low back pain to bending or lifting despite recent efforts to reduce manual workplace demands (lifting) on nurses. Strategies for managing low back pain differed between nursing students and graduate nurses., Conclusions: These results may suggest a rise in occupational exposure from student to working nurse is the primary cause of the increase in low back pain. Increased exposure may be to physical as well as psychological stressors. Given that prevalence rates are very high prior to commencing work, nursing student populations should be a target group for low back pain preventative strategies.

Introduction: Anemia is an inevitable outcome of chronic renal failure due to the kidney's decreased ability to produce erythropoietin (EPO). We examined the feasibility of isolating and expanding EPO-producing cells for cell-based therapy., Materials and Methods: Renal cells from 7- to 10-day-old mice were culture-expanded. The cells at each subculture stage were characterized for EPO expression, using immunocytochemistry, FACS, and Western Blot analysis, with EPO-specific antibodies. To assess the levels of EPO expression, cells incubated under normoxic and hypoxic conditions were analyzed., Results: Immunocytochemical analysis of the cultured renal cells expressed EPO at each subculture stage (P1-P3). Western Blot analysis of the detergent-solubilized cell extracts detected EPO (34 kDa) protein in the kidney cells of all passages tested., Conclusion: These results demonstrate that EPO-producing renal cells can be grown and expanded in culture. The cells stably expressed EPO at multiple subculture stages and they are able to form tissue in vivo. This study shows that EPO-producing cells may be used as a potential treatment option for anemia caused by chronic renal failure.

The importance of feathers for the avian group has made them one of the most studied epidermal structures both from the morphological and evolutionary point of view. Surprisingly, our observations by Scanning Electron Microscopy detected the presence of two structures widely distributed within different avian groups and not yet described. In this paper we describe these two new structures (Spina cortica and Tapetum spinosus) and map their distribution within modern birds. The S. cortica is a thorn-like microstructure that grows on the barb cortex and the T. spinosus is the assemblage of these thorns. The distribution of these new structures among birds and their morphological diversity could be of great interest to taxonomists and evolutionary biologists interested in the origin of bird flight.

Objective: The 3-D posture and muscle activity in the neck and upper limb were assessed in children using high-, mid-, and book-level displays, which correspond to working conditions frequently observed when children interact with computers or books and paper., Background: The 3-D posture and muscle activity of children reading and inputting data with computers and paper had not been previously assessed., Methods: Twenty-four children aged 10 to 12 years and of normal height performed an interactive task involving reading from a book and writing on paper or reading from a computer display and inputting data using a mouse and keyboard., Results: Head and neck flexion increased as the visual target was lowered. The high display resulted in mainly upper cervical relative extension, and the book display resulted in both upper and lower cervical flexion. The book condition resulted in greater cervical erector spinae and upper trapezius activity than did the mid and high conditions., Conclusion: The data suggest that a mid-level display may be more appropriate for children than a high display (e.g., when the display is placed on top of the central processing unit). The mid display also results in a more upright and symmetrical posture and lower mean muscle activity than does working with books and paper flat on the desk., Application: This study provides short-term laboratory study evidence for the formulation of guidelines for workstation design and adjustment for children. Use of computers by children is increasing, yet ergonomic guidelines lag behind those for adults.

This study compared the cardiovascular responses and energy costs of new and traditional screen based entertainments, as played by twenty 9- to 12-year-old children. Playing traditional electronic games resulted in little change to heart rate or energy expenditure compared with watching a DVD. In contrast, playing an active-input game resulted in a 59% increase in heart rate (p < .001) and a 224% increase in energy expenditure (p < .001) for boys and girls. The average heart rate of 130 bpm and energy expenditure of 0.13 kcal . min-1 . kg-1 achieved during active-input game use equates with moderate intensity activities such as basketball and jogging. Active-input electronic games might provide children with opportunities to engage with technology and be physically active at the same time.

Study Design: A cross-sectional comparative study between healthy controls and two subgroups of nonspecific chronic low back pain (LBP) patients., Objectives: To determine differences in trunk muscle activation during usual unsupported sitting., Summary of Background Data: Patients with LBP commonly report exacerbation of pain on sitting. Little evidence exists to confirm that subgroups of patients with nonspecific chronic LBP patients use different motor patterns in sitting than pain-free controls., Methods: A total of 34 pain-free and 33 nonspecific chronic LBP subjects were recruited. Two blinded clinicians classified nonspecific chronic LBP patients into two subgroups (active extension pattern and flexion pattern). Surface electromyography (sEMG) was recorded from five trunk muscles during subjects' unsupported "usual" and "slumped" sitting., Results: No differences in trunk muscle activity were observed between healthy controls and nonspecific chronic LBP groups for usual sitting. When the classification system was applied, differences were identified. Compared with no-LBP controls, the active extension pattern group presented with higher levels of cocontraction of superficial fibers of lumbar multifidus (12%), iliocostalis lumborum pars thoracis (36%) and transverse fibers of internal oblique (43%). while the flexion pattern group showed a trend toward lower activation patterns (lumbar multifidus, -7%; iliocostalis lumborum pars thoracis, -6%, and transverse fibers of internal oblique, -5%). The flexion relaxation ratio of the back muscles was lower for nonspecific chronic LBP (superficial lumbar multifidus: t = 4.5; P < 0.001 and iliocostalis lumborum pars thoracis:t = 2.7; P < 0.001), suggesting a lack of flexion relaxation for the nonspecific chronic LBP., Conclusion: Subclassifying nonspecific chronic LBP patients revealed clear differences in sEMG activity during sitting between pain-free subjects and subgroups of nonspecific chronic LBP patients.

Background: Increasing use of computers by children has raised concerns over the potential impact on their cognitive, social, educational, visual and physical development. Despite this concern, there are no large-scale studies relating the use of computers to specific health indicators in children as they reach school age., Methods: A cross-sectional analysis of 1600 5-year-old Western Australian children participating in a longitudinal cohort study was conducted to ascertain their computer use, other activities (watching television and videos, playing electronic games, reading and looking at books, drawing on paper and moderate to vigorous physical activity), and specific health indicators., Results: More than half (56%) of the children used computers each week. Computer use was significantly related to TV viewing (OR 1.97 weekday) and electronic game use (console games OR 2.48 weekday, 1.81 weekend; hand-held games OR 1.88 weekend) and negatively associated with vigorous physical activity on weekends (OR 0.72). Computer use was also significantly related to socio-economic indicators such as the mother being older (40+ years, OR 1.70 weekend, 1.73 weekday), tertiary educated (OR 1.63 weekend) and studying (OR 1.52 weekend, 1.41 weekday). Almost 1% children were reported to have complained of tired or sore muscles, and 2.2% had complained of tired or sore eyes, after watching television or using a computer., Conclusion: A substantial proportion of 5-year-old Western Australian children are using computers. Computer use was related to other sedentary activities and less vigorous activity. While musculoskeletal and vision problems are not widespread, their presence and the sedentary nature of computer use is of public health concern.

Study Design: A comparative study., Objectives: To investigate sitting postures of asymptomatic individuals and nonspecific chronic low back pain (NS-CLBP) patients (pooled and subclassified) and evaluate the importance of subclassification., Summary of Background: Currently, little evidence exists to support the hypothesis that CLBP patients sit differently from pain-free controls. Although classifying NS-CLBP patients into homogeneous subgroups has been previously emphasized, no attempts have been made to consider such groupings when examining seated posture., Methods: Three angles (sacral tilt, lower lumbar, and upper lumbar) were measured during "usual" and "slumped" sitting in 33 NS-CLBP patients and 34 asymptomatic subjects using an electromagnetic measurement device. Before testing, NS-CLBP patients were subclassified by two blinded clinicians. Twenty patients were classified with a flexion motor control impairment and 13 with an active extension motor control impairment., Results: No differences were found between control and NS-CLBP (pooled) patients during usual sitting. In contrast, analyses based on subclassification revealed that patients classified with an active extension pattern sat more lordotic at the symptomatic lower lumbar spine, whereas patients with a flexion pattern sat more kyphotic, when compared with healthy controls (F = 19.7; df1 = 2, df2 = 63, P < 0.001). Further, NS-CLBP patients had less ability to change their posture when asked to slump from usual sitting (t = 4.2, df = 65; P < 0.001)., Conclusions: Differences in usual sitting posture were only revealed when NS-CLBP patients were subclassified. This highlights the importance of subclassifying NS-CLBP patients.

The importance of classifying chronic low back pain (LBP) patients into homogeneous sub-groups has recently been emphasized. This paper reports on two studies examining clinicians ability to agree independently on patients' chronic LBP classification, using a novel classification system (CS) proposed by O'Sullivan. In the first study, a sub-group of 35 patients with non-specific chronic LBP were independently classified by two 'expert' clinicians. Almost perfect agreement (kappa-coefficient 0.96; %-of-agreement 97%) was demonstrated. In the second study, 13 clinicians from Australia and Norway were given 25 cases (patients' subjective information and videotaped functional tests) to classify. Kappa-coefficients (mean 0.61, range 0.47-0.80) and %-of-agreement (mean 70%, range 60-84%) indicated substantial reliability. Increased familiarity with the CS improved reliability. These studies demonstrate the reliability of this multi-dimensional mechanism-based CS and provide essential evidence in a multi-step validation process. A fully validated CS will have significant research and clinical application.

Study Design: A single-group comparative study., Objectives: To compare lumbopelvic kinematics and muscle activation patterns while sitting on stable and unstable surfaces., Background: Unstable surfaces are commonly used during the rehabilitation of certain low back pain disorders. The benefits postulated are increased muscle activity and facilitation of sustainable midrange positions via neuromuscular control. The use of unstable sitting devices in the workplace is controversial, as the postulated increase in muscle activity is thought to lead to a muscle fatigue/pain response. However, little evidence exists for or against the ability of these devices to alleviate or prevent spinal pain., Methods and Measures: This study included 26 healthy adults (14 male, 12 female). Fastrak 3-dimensional motion analysis detected lumbar curvature, pelvic tilt, and postural sway during sitting on a stable and unstable surface over 5-minute periods. Surface electromyography was used to measure activity in the superficial lumbar multifidus, transverse fibers of internal oblique, and iliocostalis lumborum pars thoracis., Results: Spinal postures were similar for sitting on a stable and unstable surface. Significant increases in postural sway were detected (P = .013) in 3 dimensions of movement during sitting on an unstable surface. Gender differences were noted. No EMG amplitude or variance differences were detected between seating conditions., Conclusions: Preliminary data show that sitting on unstable surfaces induces greater spinal motion, but does not significantly alter the lumbosacral posture nor the amount of activity in the superficial trunk muscles under investigation.

This paper outlines the major changes in the lives of children in industrially advanced countries associated with the increased interaction with information and communication technologies. The potential opportunities and threats to the cognitive, social, physical and visual development of children are reviewed to emphasize the importance of optimizing the interaction. The change in children's use of technology also poses opportunities and threats for ergonomics that should be noted if the profession is to continue being relevant and useful into this century. The paper ends with a pathway to the development and implementation of guidelines about child information and communication technology use for different groups of guideline users.

The objective of this study was to quantitatively analyse the sitting posture of school children interacting with both old (book) and new (laptop and desktop computers) information technologies to test the hypothesis that posture is effected by the type of information technology (IT) used. A mixed model design was used to test the effect of IT type (within subjects) and age and gender (between subjects). The sitting posture of 32 children aged 4-17 years was measured whilst they read from a book, laptop, and desktop computer at a standard school chair and desk. Video images were captured and then digitized to calculate mean angles for head tilt, neck flexion, trunk flexion, and gaze angle. Posture was found to be influenced by IT type (p < 0.001), age (p < 0.001) and gender (p = 0.024) and significantly correlated to the stature of the participants. Measurement of resting posture and the maximal range of motion of the upper and lower cervical spines in the sagittal plane was also undertaken. The biophysical impact and the suitability of the three different information technologies are discussed.

A participative ergonomics approach to reducing injuries associated with manual tasks is widely promoted; however only limited evidence from uncontrolled trials has been available to support the efficacy of such an approach. This paper reports on a randomized and controlled trial of PErforM, a participative ergonomics intervention designed to reduce the risks of injury associated with manual tasks. One hundred and seventeen small to medium sized food, construction, and health workplaces were audited by government inspectors using a manual tasks risk assessment tool (ManTRA). Forty-eight volunteer workplaces were then randomly assigned to Experimental and Control groups with the Experimental group receiving the PErforM program. Inspectors audited the workplaces again, 9 months following the intervention. The results showed a significant decrease in estimates of manual task risk and suggested better legal compliance in the Experimental group.

Poor neck and shoulder postures have been suggested to be a cause of neck and shoulder pain in computer workers. The present study aimed to evaluate and compare the head, neck and shoulder postures of office workers with and without symptoms in these regions, in their actual work environments. The two all female subject groups reported significantly different discomfort scores across five trials repeated in a single working day. The results of repeated video capture and two-dimensional motion analysis showed that there were trends for increased head tilt and neck flexion postures in the symptomatic subjects (n = 8), compared to the asymptomatic subjects (n = 8). Symptomatic subjects also tended to have more protracted acromions compared with asymptomatic subjects and showed greater movement excursions in the head segment and the acromion. All subjects demonstrated an approximately 10% increase in forward head posture from their relaxed sitting postures when working with the computer display, but there were no significant changes in posture as a result of time-at-work.

This paper reports on a study of environments in emerging Internet classrooms. At issue for this study is to what extent these 'technological classrooms' are providing a positive learning environment for students. To investigate this issue, this study involved an evaluation of the physical and psychosocial environments in computerized school settings through a combination of questionnaires and inventories that were later cross-referenced to case studies on a subset of these classrooms. Data were obtained from a series of physical evaluations of 43 settings in 24 school locations in British Columbia, Canada and Western Australia. Evaluations consisted of detailed inventories of the physical environment using the Computerised Classroom Environment Inventory (CCEI): an instrument developed specifically for this study. Data on psychosocial aspects of the environment were obtained with the What is Happening in this Class? (WIHIC) questionnaire administered to 1404 high school students making routine use of these computerized classrooms. Potential deficiencies in the physical environment of these locations included problems with individual workspaces, lighting and air quality, whereas deficiencies in the psychosocial environment were confined to the dimension of Autonomy. Further analysis of these classroom environment data indicated that student Autonomy and Task orientation were independently associated with students' Satisfaction with learning and that many physical (e.g. lighting and workspace dimensions) and psychosocial factors (e.g. students' perceptions of Co-operation and Collaboration) were also associated. The results provide a descriptive account of the learning environment in 'technology-rich' classrooms and, further, indicate that ergonomic guidelines used in the implementation of IT in classrooms may have a positive influence on the learning environment.

Psychophysical and psychological criteria are accepted risk measures for manual handling task assessment, yet few reports have compared squat and stoop using these criteria. Seventeen university students participated in a within-subjects cross over design study to compare squat and stoop techniques using maximum acceptable weight (MAW), perceptions of exertion (RPE), discomfort and preference. Mean (SD) MAW for squat was lower than for stoop (7.0 (2.2) kg vs 8.5 (2.4) kg) and RPE for squat was greater than for stoop (15.2 (1.5) kg vs 13.3(1.5) kg). More subjects reported discomfort following squat and a preference for stoop. The results provide limited support for use of stoop rather than squat technique for lifting a medium sized box from floor to knuckle height.

This paper is the first of a series aimed at providing clinicians with a guide to assist them in using work-related assessments appropriately. The context of work-related assessments is described using a model. The purposes of work-related assessments are classified and discussed using the proposed model. The 10 major problems facing clinicians using work-related assessments are outlined. Companion papers describe the design, administration and interpretation problems in detail.

This paper is the third of a series aimed at providing clinicians with a guide to assist them in using work-related assessments appropriately. The major administration and interpretation problems facing clinicians using work-related assessments are described in detail. Administration problems are: (1) insufficient evidence of reliability and validity; and (2) potential examiner bias. Interpretation problems are: (1) inappropriate use of norm and criterion-referenced data; (2) inappropriate statistical manipulation of results; (3) difficulty in determining end-point; and (4) difficulty determining sincerity of effort. Companion papers describe the purposes of work-related assessments, and design problems in detail.

This paper is the second in a series aimed at providing clinicians with a guide to assist them in using work-related assessments appropriately. This paper discusses the four major design problems facing clinicians using work-related assessments. These problems are: (1) a confused definition of terms; (2) confused conceptual basis; (3) separation of the individual from the context and the environment; and (4) lack of assessment of psychosocial/cognitive aspects related to work. Suggestions are provided to assist clinicians in making decisions regarding work-related assessments. Recommendations for further research to ameliorate these problems are also made. Companion papers describe the purposes of work-related assessments, and administration and interpretation problems in detail.

This study evaluated the postural implications of using a laptop computer. Laptop computer screens and keyboards are joined, and are therefore unable to be adjusted separately in terms of screen height and distance, and keyboard height and distance. The posture required for their use is likely to be constrained, as little adjustment can be made for the anthropometric differences of users. In addition to the postural constraints, the study looked at discomfort levels and performance when using laptops as compared with desktops. Statistical analysis showed significantly greater neck flexion and head tilt with laptop use. The other body angles measured (trunk, shoulder, elbow, wrist, and scapula and neck protraction/retraction) showed no statistical differences. The average discomfort experienced after using the laptop for 20 min, although appearing greater than the discomfort experienced after using the desktop, was not significantly greater. When using the laptop, subjects tended to perform better than when using the desktop, though not significantly so. Possible reasons for the results are discussed and implications of the findings outlined.

Work-associated back problems are a major problem in the British National Health Service. Attempts to reduce the problem can only be judged when effective measuring and monitoring systems are available. This article highlights the problems associated with some currently available systems and describes a new system developed especially for the health service. Examples of the use of the new system are given to demonstrate its potential.

Work-associated back problems are a major health issue for which the traditional approaches of manual skills training and worker selection have demonstrated little effect. The common alternative, direct ergonomics intervention, risks work group resentment and non-compliance problems. This paper describes a new ergonomics training approach which changes the role and content of training to facilitate staff and management collaboration.