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.     

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.     

Effects of seated lumbar extension postures on spinal height and lumbar range of motion during prolonged sitting

Prolonged sitting during sedentary work has been reported as a potential risk factor for low back pain. Furthermore, prolonged sitting can result in both reduced spinal height (SH) and lumbar range of motion (LROM). This study compared the effects of no intervention (control) with two recovery postures on SH and LROM (flexion and extension) during prolonged sitting. Twenty-four participants were randomly assigned to three interventions for three consecutive days. The interventions comprised two seated lumbar extension recovery postures (unsupported sustained and supported dynamic lumbar extension postures) and a control. Both interventions facilitated a relatively short recovery period for both SH and LROM. Supported dynamic lumbar extension conditions significantly helped SH recovery, as compared with control condition, after the first recovery posture intervention, and both postures have potential to maintain LROM. However, both postures failed to induce SH recovery over an extended time.     

Inter- and intra-tester reliability when measuring seated spinal postures with inertial sensors

Prolonged awkward sitting postures may be associated with neck or back pain, but it is often unclear which specific postures cause most problems and which mechanisms that may underlie the pain. In order to increase the knowledge in this field, it seems crucial first of all to be able to analyse, in depth, different seated spinal postures. A problem is however the lack of reliable and direct measurement methods of the posture, especially for sitting. Recently developed systems with inertial sensor attached along the spine have potential for this purpose. The aim of the present study was therefore to test the reliability of using such a system to assess various seated postures.     

Studying the relationship between low back pain and working postures among those who stand and those who sit most of the working day

A relationship between low back pain (LBP) and prolonged standing or prolonged sitting at work has not been clearly shown, despite its biological plausibility. Because sitting and standing postures vary as to duration and freedom to alternate postures, and standing postures vary as to mobility, associations between specific working postures and LBP were explored using multiple logistic regression. Associations between work factors and self-reported LBP during the previous 12 months that interfered with usual activities were examined among 4493 standing workers and 3237 sitting workers interviewed in the 1998 Quebec Health and Social Survey; 24.5% reported significant LBP. Since the same conditions can correspond to different physiological demands for sitting compared with standing workers, analyses were performed separately for the two groups. Standing without freedom to sit was associated with LBP. Different occupational physical and psychosocial factors were associated with LBP in sitting compared with standing populations.     

A portable ergonomic observation method (PEO) for computerized on-line recording of postures and manual handling

A new portable ergonomic observation method (PEO) is presented. It is applicable to most professions and work tasks and requires only moderate human resources for data collection and analysis. Observations are made in real time directly at the workplace using a portable personal or hand-held computer, and data are accessible for immediate analysis and presentation. Duration and number of events are calculated for postures at four body regions (arms, neck, trunk and knee) as well as for manual handling. An evaluation of the PEO method, assessing some important aspects of internal validity as well as intra- and inter-observer reliability, was carried out using video recordings. It showed acceptable validity for some types of physical exposure, and high intra- and inter-observer reliability. Practical experiences from using the PEO method in a field study and further improvements of the method are discussed.     

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.     

Sitting and standing postures are corrected by adjustable furniture with lowered muscle tension in high-school students

This study compared the effect of 24 months of adjustable school desks and chairs usage (the intervention) and traditional non-adjustable usage (the control condition) on sitting and standing postures, muscle strength, classroom muscle tension, pain and learning in 15 (8 female and 7 male) high-school students and 15 anthropometrically and gender matched control students from neighbouring schools. It was assessed whether any responses took place after growth cessation. In comparison with controls, the intervention group of students' sitting postures standing kyphosis, scoliosis and lordosis became significantly better, both before and after growth cessation. Trunk muscle strength increased in the intervention students whose muscle tension during classes fell significantly in the trapezius and lumbar muscles, whereas in control students' lumbar tension increased. Headache and low-back pain correlated with neck-shoulder pain and trapezius muscle tension. Intervention students reported that they experienced benefits from the adjustable tables and chairs. They also received significantly better overall marks than the controls at the end of high school. It is concluded that the adjustable school desks and chairs promoted better sitting and standing postures, increased muscle strength, alleviated pain and appeared to be associated with better overall academic marks.     

Background to sitting at work: research-based requirements for the design of work seats

The body's responses to sitting are complex and involve the anatomy and physiology of the sitter as well as the structure of the seat, the desk and the environment. In the light of recent research, the major reactions of the spine, the muscles and the spinal discs are discussed. Their interactions when adopting sitting postures are described. Reasons are given why certain sitting postures are to be preferred. The mechanisms that may give rise to muscle and disc damage, as well as back pain, as a result of adverse sitting postures are outlined. The design consequences of the research are then presented, showing how the seat shape arises from the previously described data. The influence of backrest design on sitting comfort and in the reduction of loading on the body is shown. Finally, a brief discussion of the influences from the work surface illustrates how the combination of seat and workplace can reduce the risks of injury by mitigating body loadings over the working day.     

A field comparison of neck and shoulder postures in symptomatic and asymptomatic office workers

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.     

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.     

An evaluation of the effect of a training program on worker lifting postures

Though worker training is often chosen as a means to reduce the risk of low back pain if involved in lifting activities, the effect on a worker's lifting posture is rarely reported. This paper describes a video analysis method of recording lifting postures and the results of one evaluation of a training program specifically designed to modify lifting postures. It is concluded that a four-hour training program had beneficial but minor effects on the lifting techniques used by healthy workers in a warehouse when handling relatively light to moderate loads (i.e., 85% of loads lifted were below 30 pounds).     

Lumbar posture and trunk muscle activation during a typing task when sitting on a novel dynamic ergonomic chair

Low back pain (LBP) is a common musculoskeletal disorder and prolonged sitting often aggravates LBP. A novel dynamic ergonomic chair (‘Back App’), which facilitates less hip flexion while sitting on an unstable base has been developed. This study compared lumbar posture and trunk muscle activation on this novel chair with a standard backless office chair. Twelve painfree participants completed a typing task on both chairs. Lumbar posture and trunk muscle activation were collected simultaneously and were analysed using paired t-tests. Sitting on the novel dynamic chair significantly (p < 0.05) reduced both lumbar flexion and the activation of one back muscle (Iliocostalis Lumborum pars Thoracis). The discomfort experienced was mild and was similar (p > 0.05) between chairs. Maintaining lordosis with less muscle activation during prolonged sitting could reduce the fatigue associated with upright sitting postures. Studies with longer sitting durations, and in people with LBP, are required.

Practitioner Summary: Sitting on a novel dynamic chair resulted in less lumbar flexion and less back muscle activation than sitting on a standard backless office chair during a typing task among pain-free participants. Facilitating lordotic sitting with less muscle activation may reduce the fatigue and discomfort often associated with lordotic sitting postures.     

Subjective response to whole-body vibration The effects of posture

In an investigation of the effects of posture on subjective responses to whole-body vibration, 20 undergraduate subjects produced equal sensation contours adopting three postures each on different occasions. The postures adopted were standing, sitting upright and sitting slouched.

The results indicated significant differences in the contour shapes from the three postures, and the level set in the sitting postures were significantly lower than in the standing posture. No difference was obtained between the two sitting postures.

Implications of these findings are discussed regarding the role of transmissibility in subjective response to vibration, and the necessity to produce different standards for different postures.     

Background to sitting at work: research-based requirements for the design of work seats

The body's responses to sitting are complex and involve the anatomy and physiology of the sitter as well as the structure of the seat, the desk and the environment. In the light of recent research, the major reactions of the spine, the muscles and the spinal discs are discussed. Their interactions when adopting sitting postures are described. Reasons are given why certain sitting postures are to be preferred. The mechanisms that may give rise to muscle and disc damage, as well as back pain, as a result of adverse sitting postures are outlined. The design consequences of the research are then presented, showing how the seat shape arises from the previously described data. The influence of backrest design on sitting comfort and in the reduction of loading on the body is shown. Finally, a brief discussion of the influences from the work surface illustrates how the combination of seat and workplace can reduce the risks of injury by mitigating body loadings over the working day.     

Work activities and musculoskeletal complaints among preschool workers

The potential for musculoskeletal trauma among preschool workers has been largely unexplored in the United States. This case report describes an investigation conducted to identify and evaluate possible causes of back and lower extremity pain among 22 workers at a Montessori day care facility. Investigators met with and distributed a questionnaire to school employees, and made measurements of workstation and furniture dimensions. Investigators also recorded the normal work activities of school employees on videotape, and performed a work sampling study to estimate the percentage of time employees spend performing various tasks and in certain postures.

Questionnaire results from 18 employees indicated that back pain/discomfort was a common musculoskeletal complaint, reported by 61% of respondents. Neck/shoulder pain, lower extremity pain and hand/wrist pain were reported by 33, 33 and 11% of respondents, respectively. Observation and analysis of work activities indicated that employees spend significant periods of time kneeling, sitting on the floor, squatting, or bending at the waist. Furthermore, staff members who work with smaller children (i.e. six weeks to 18 months of age) performed more lifts and assumed more awkward lower extremity postures than employees who work with older children (3–4 years of age). Analysis of two lifting tasks using the revised NIOSH lifting equation indicated that employees who handle small children may be at increased risk of lifting-related low back pain. Investigators concluded that day care employees at this facility are at increased risk of low back pain and lower extremity (i.e. knee) injury due to work activities that require awkward or heavy lifts, and static working postures. Recommendations for reducing or eliminating these risks by modifying the workplace and changing the organization and methods of work are presented.     

An evaluation of comfort of a bus seat

The aim of this research was to evaluate the comfort of a passenger seat for a new type of bus. A fuzzy set model of a multistage comfort scale (MCS) was adopted for the assessment of comfort, together with the techniques of human back shape and EMG measurements as well as posture analysis. The subjects were 30 university students. It is concluded that MCS is a rapid but comprehensive evaluation method for single chair evaluation. The overall rating of MCS is 0.532, which is acceptable under the conditions of the prototype evaluation. The seat profile fits better with the back curve of subjects who had higher comfort rating in the way that the upper profile of the seat coincides with the human back curve and the lower part of the profile intersects the human back curve in the lumbar region; here the human back curves were measured in the slumped sitting posture. There was a significant difference in the EMGs of back muscles between the two sitting postures (sitting upright and the slumped sitting posture) at all the seat heights.     

The effect of dynamic sitting on the prevention and management of low back pain and low back discomfort: a systematic review

Dynamic sitting has been proposed to reduce low back pain (LBP) and/or low back discomfort (LBD) while sitting. This is supported by studies suggesting that subjects with LBP assume more static, sustained postures while sitting. This systematic review investigated the effect of dynamic sitting on LBP among subjects with LBP and the development of LBD among pain-free subjects. Electronic databases were searched by two independent assessors. All prospective studies which compared the effect of a dynamic sitting condition on LBP or LBD to another sitting condition were eligible, with no minimum follow-up period applied. The quality of the included studies was assessed using the PEDro scale. Seven high-quality studies were eligible, including five crossover studies and two randomised controlled trials. The results suggest there is currently no evidence to support the use of dynamic sitting as a stand-alone approach in the management of LBP. PRACTITIONER SUMMARY: This systematic review investigated the effect of dynamic sitting on LBP or LBD. Seven high-quality studies met the inclusion and exclusion criteria. Overall, the evidence suggests that dynamic sitting approaches are not effective as a stand-alone management approach for LBP.     

Load moments and myoelectric activity when the cervical spine is held in full flexion and extension

Abstract

Sustained joint load in extreme positions (namely maximally flexed or extended positions) has been described as causing pain. The aim of the present study is to analyse eight different sitting work postures with respect to extreme positions, and to assess the mechanical load and the levels of muscular activity arising in defined extreme positions of the cervical spine. Ten healthy female workers from an electronics plant took part in laboratory experiments. For seven of these, levels of neck and shoulder muscular activity in sitting postures with the cervical spine in different manually-adjusted extreme positions were recorded using surface electrodes. Loading moments of force about the bilateral motion axis of the atlanto-occipital joint (Occ-C1) and the spinal cervico-thoractc motion segments (C7-T1) were calculated. Extreme or almost extreme positions occurred in sitting postures with the thoracolumbar back inclined slightly backwards or with the whole spine flexed. Electromyographic (EMG) activity levels were very low in the manually-adjusted extreme positions. The load moment for the Occ-Cl joint when the whole neck was flexed was only 1·2 times the value for the neutral position of the head, but for C7-T1 it increased to 3·6 times. It is concluded that extreme positions of the cervical spine do occur in sitting work postures, and that the levels of muscular activity in such positions are low. Thus, recordings of muscle activity and calculations of load moment alone are not a sufficient basis for evaluating work postures: thorough recordings of spine positions should be included.     

Seated buttock contours: a pilot study of Australian senior high-school students

Both posture and comfort of a chair are influenced by the contour and characteristics of the seat. Knowledge of seat contours of a student population could thus be useful in the design of school chairs. This study investigated seated buttock contours of senior high-school students in order to determine: (a) their general characteristics, (b) the effect of gender and sitting posture and (c) the relationship between the contours and selected anthropometric variables (stature and mass). A contour measurement device was developed and used to measure buttock contours in five sitting postures (typing, sitting up, sitting back, slumping and writing). Buttock contours were quantified by constructing anterior-posterior (AP) and lateral profiles from which six discrete profile dimension measurements were made. AP and lateral profiles were found to have a consistent shape across all participants. Five out of six profile dimensions were significantly different between genders, with just one significantly different between sitting postures (typing and sitting back). Correlations between anthropometric measures and profile dimensions were relatively low (r < 0.34) with no clear patterns evident. Overall results of this study suggest that buttock contours are influenced by gender to a greater extent than sitting posture.