Back Posture Research Articles

The prognostic value of the quality of life parameters in patients with idiopathic scoliosis treated operatively (Poster)

implemented as a means of quantifying posture in physiotherapy departments in the near future. Objectives: The first objective of this study was to devise a protocol for use with patients with different spinal dysfunctions. The second objective was to produce a database of normative back shape values in young adults. These baseline values would then enable the comparison of subjects with healthy backs to the backs of patients with spinal problems. Subjects: 100 healthy subjects aged 20–40 years old were recruited. Subjects were excluded if they had any lower limb or back injury that prevented the subject standing for the duration of data collection. Instrumentation: This study used a relatively low-cost (<£3000), portable system, known as the MIDAS (Middlesbrough Integrated Digital Assessment System), with software specifically designed for the assessment of back posture. Procedure: The patient was positioned in front of the MIDAS, allowing measurement of landmarks of their back for posture assessment. Data collection involved one tester touching the MIDAS stylus tip to each of the marked points in a standardized order dictated by the software and pressing the foot pedal of the MIDAS to store the position on the computer. Results: The results indicate that overall young adults are very symmetrical. The mean distances between the left and right sides of the back and the average values were then calculated. Only the distance between the scapula and the acromion process was significantly smaller on the left side than the right side. It is possible that this is related to the fact that most subjects were right handed. A map of 3D back patient values for normative distances and angles was produced and will be shown at the presentation. Conclusions: Our results will provide a normative database for clinicians (physiotherapist, chiropractors, spinal surgeon) who routinely assess back posture. The method we have devised will also provide an evidenced based objective alternative to just ‘‘eyeballing’’ back posture during clinical evaluation.

A new low cost method for the assessment of patients with poor back posture and scoliosis: 3D Mapping of 100 Subjects (Poster)

mally managed. Thus, as health care team members it is important to identify, prevent and treat this complication in order to improve the quality of life for our patients. Purpose: To discuss the causes of post operative delirium, its prevention and management. Method: Systemic review of 20 articles, qualitative and quantitative; published in international journals and websites in the past 10 years. Results: The elderly with cognitive and functional impairments and multiple co-morbidities are particularly at risk of delirium. The major causes are long hospital stays, decreased independence, complications and metabolic and potential central nervous system disorders. Sleep deprivation and the use of opiates that increase dopamine levels and decrease acetylcholine levels also contribute to delirium. According to the literature, prevention of delirium is achieved by addressing the underlying causes, maintaining behavioural control, preventing complications and supporting the functional needs of the patient. Prevalence of delirium may also be reduced with early geriatric consultation and structured multidisciplinary intervention programs. Additionally, supportive care, patient and family education, early mobilization, and provision of appropriate environmental orientation are integral in the management of delirium. Moreover, ensuring adequate oxygen delivery, restoring fluid and electrolyte balance and treating pain help manage delirium. Conclusion: Delirium has very high morbidity and mortality rates. Thus, as health care professionals we need to realize the importance of prompt recognition and management of this condition in order to prevent our patients from falling prey to it.

Creep and Fatigue Development in the Low Back in Static Flexion

In vivo measurements of low back flexion posture and muscle activity before, during, and after static flexion. To identify the occurrence of creep and muscle fatigue development in the low back during static upper body deep flexion that resembled an above ground work posture. Static lumbar flexion has been related to the development of low back disorders, and its injury mechanism has been focused on the changes in passive spinal tissues. Potential influences of muscle fatigue of extensor muscles have not been explored. A total of 20 asymptomatic subjects performed submaximal isometric trunk extension exertions and an isokinetic trunk flexion before and immediately after 5-minute static flexion while the trunk sagittal flexion angle and the myoelectric activities (electromyography [EMG]) of back extensor muscles were recorded simultaneously. Changes in the flexion-relaxation onset angle, maximum flexion angle, muscle activity level, and the median power frequency of EMG associated with the static flexion were evaluated. Flexion-relaxation onset angle in isokinetic flexion and EMG amplitude of isometric extension were significantly greater after static flexion, indicating creep of spinal tissues in static flexion. Median power frequency of lumbar erector spinae EMG during isometric extension was significantly lower after static flexion, suggesting the development of muscle fatigue. Consistent but low level of EMG was observed together with sporadic muscle spasms during the static flexion period. Fatigue of low back extensor muscles may occur in static flexion due to prolonged passive stretching of the muscles. Low back extensor muscles are required to generate more active forces in weight holding or lifting after static flexion to compensate for the reduced contribution of creep deformed passive tissues in maintaining spinal stability and the posture. The degraded force generating capacity of the fatigued muscles can be a significant risk factor for low back pain.

Mountain rescue stretchers: Usability trial

In the UK mountain rescues are carried out by highly trained volunteers in all weather conditions and at any time of the day/night. They interface with other services when they hand over the casualty to either land or air ambulances. The design of the stretcher is important to the safety of both the volunteers and casualties. This paper reports a usability trial to evaluate the features of mountain rescue stretchers and identify characteristics for future design. Two mountain rescue teams in the English Lake District participated in a five week field experiment. Data were collected using postural analysis with Rapid Entire Body Analysis, Body Part Discomfort Surveys, Rated Perceived Exertion and focus groups to compare the performance of four stretchers: Split Thomas, Ferno Titan, MacInnes mark 6 and MacInnes mark 7. None of the stretchers had an overall advantage, with benefits for some features counterbalanced by disadvantages resulting from others. All the stretchers produced shoulder discomfort with the Split Thomas and MacInnes 6 lowering the postural risks through the use of skids/wheel in the carrying phase. The key design features for future MR stretchers include: reduced unloaded weight (e.g. light weight materials and mesh platforms); undercarriage system to reduce the carrying load; adjustable handles at the front and back positions; flexible carrying system with an optional harness attachment; ease of assembly in adverse environmental conditions; large carrying capacity. It is suggested that military emergency evacuation should be considered in addition to mountain rescue tasks to identify a larger commercial market for development.

Rehabilitative ultrasound imaging is a valid measure of trunk muscle size and activation during most isometric sub-maximal contractions: a systematic review

Is rehabilitative ultrasound imaging a valid measure of trunk muscle size and activation? Are rehabilitative ultrasound imaging measures sensitive to change? Systematic review of studies of criterion-related validity, construct validity, and sensitivity to change. People with low back pain and asymptomatic controls. Trunk muscle size and activation measured by rehabilitative ultrasound imaging, MRI and/or EMG. 37 studies were included. 10 studies investigated criterion-related validity and provided evidence that while ultrasound may be a valid measure of trunk muscle size, the validity of ultrasound to quantify muscle activation is context-dependent, depending on the muscle involved, the contraction strategy utilised, and the intensity of muscle contraction. 23 studies provided evidence of construct validity by demonstrating the ability of ultrasound measurement to differentiate individuals in terms of back pain, anthropometry, and postures. Six studies contained a limited amount of information about sensitivity to change. CONCLUSIONS. It is valid to use rehabilitative ultrasound imaging to measure trunk muscle size and activation during most isometric sub-maximal contractions. Ultrasound measures appear sensitive to both positive and negative change.

Posture Evaluation of Dental Students

Correct dentist posture and position during clinical work are of great importance to prevent neck, back pain and muscle fatigue. Therefore, this observational survey was conducted to evaluate the posture of dental students in King Abdulaziz University (KAU) during clinical procedures. Thereafter, recommendations were given in order to improve errors in existing postures. Almost 300 dental students from the third through the sixth grades were observed randomly during their clinical sessions. The evaluation included: the patient's chair position, the student's chair, back and elbow positions depending on the quadrant treated. Furthermore, whether viewing the operative field in a direct or indirect manner and the type of magnification used during clinical work, if any. Results showed that 43% of the students placed their patients' chair within normal limits (almost supine); 50% of the students' backs were bent; 33% of students' elbows were below the level of the quadrant treated; 50% of the students approached the maxillary arch directly; only 3 male students used magnifiers, and 60% of the students experienced neck or back pain after clinical work (mostly females). Therefore, it was highly recommended that students continuously evaluate and correct their whole body posture during a clinical work.

Back posture and low back muscle activity in female computer workers: A field study

Background Few studies have investigated sitting posture and low back muscle activity in occupational settings. This study aims to determine back posture and its influence on low back muscle activity in computer workers, and to investigate whether the work situation is associated with exacerbation of low back pain. Methods Twenty-one female computer workers participated. Surface electromyographic activity was recorded from lumbar multifidus, longissimus, and iliocostalis throughout the workday. Simultaneous inclinometer recordings from pelvis, upper trunk, and left thigh were used to determine back posture and identify periods with sitting, standing, and walking. Low back pain intensity was recorded by visual analogue scale every hour throughout the work and leisure periods. Findings All subjects adopted a markedly flexed back posture while seated at work. Surface electromyographic activity was very low for all muscles during sitting (group median <1.4% of root-mean-square-detected response at maximal voluntary contraction). Back posture moderately influenced electromyographic activity, accounting for 19% (sitting) to 38% (standing) of intra-individual variation in muscle activity. Subjects reporting aggravating low back pain ( n = 10) during the workday were not distinguished by duration of sitting, sitting posture, or low back muscle activity. Low back pain was markedly reduced from the last hour of work to the first hour of leisure, accompanied by an increase in low back muscle activity. Interpretation Low back muscle activity was very low during seated posture, presumably due to the flexion–relaxation phenomenon. Sustained stretch of passive lumbar structures in combination with essentially silent muscles may exacerbate low back pain in sedentary workers.

How Not to Wear a School Backpack

Orthopaedics| November 01 2008 How Not to Wear a School Backpack AAP Grand Rounds (2008) 20 (5): 58–59. https://doi.org/10.1542/gr.20-5-58 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation How Not to Wear a School Backpack. AAP Grand Rounds November 2008; 20 (5): 58–59. https://doi.org/10.1542/gr.20-5-58 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: pain, pressure-physical agent, shoulder region, skin, lower back, shoulder pads, shoulder pain Source: Macias BR, Murthy G, Chambers H, et al. Asymmetric loads and pain associated with backpack carrying by children. J Pediatr Orthop. 2008;28(5):512–517. This study from Children’s Hospital and Health Center, San Diego, described the contact pressures under backpack shoulder straps of children while they carried varying loads under different wearing conditions. Healthy young teens were recruited to carry a standard backpack loaded at 10%, 20%, and 30% of body weight (BW). Four different standardized backpack positions were tested for skin surface contact pressures under the shoulder straps utilizing sensors positioned under each strap. The backpack was placed with both shoulder straps equally adjusted for (1) a high back position between the scapula and above the pelvis as well as (2) a low back position resting on the pelvis with the shoulder straps equally adjusted. These high and low back positions were then tested with (3) the backpack carried over the left shoulder and with (4) the pack carried over the right shoulder. Contact pressures were measured while the child was standing as well as walking. Pressure thresholds greater than 30 mm Hg were assumed to occlude skin blood flow. The children rated their pain using the Borg Visual Analog Scale (BVAS: 0= no pain, 10=worst pain).1 Five girls and five boys participated. Subjects’ mean age, height, and weight were 13.2 years, 136.5 cm, and 62 kg respectively. For each of the four testing conditions the mean surface contact pressure was significantly higher with the use of one strap on the right shoulder compared to the left, with use of a low back position compared to high back position, and at 30% BW load compared to 10% or 20% BW. The least skin pressure was noted under the left shoulder strap (38 mm Hg SD ± 12 mmHg) for a 10% BW load, high back position, with both straps secured. The highest skin pressure was measured under the right shoulder strap (235 mm Hg SD ± 68) for a 30% BW load, low back position with only one strap secured. Perceived pain on the BVAS was significantly higher with the backpack in the low back position, with backpack loads of 30% BW compared to either 10% or 20%, and with use of one shoulder strap compared to two. The highest pain score (BVAS 6) was noted with a 30% BW load when one shoulder strap was used. At a 10% BW pack load the perceived pain score was <1, regardless of whether one or both shoulder straps were used. The authors conclude that children should carry backpacks in the high-back position with two straps placed over both shoulders to minimize high local pressures. Dr. Schwend has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device. Although this study evaluated only 10 healthy volunteer children, it was well controlled for age and used rigidly applied testing conditions. A skin surface pressure... You do not currently have access to this content.

O.421 The relationship between jaw deformity and scoliosis

A debate remains in evidence-based medicine about the reciprocal interchange between dental occlusion and body postural therapy. Back posture deformity has been found to be related to trunk asymmetry as one characteristic of scoliosis that is commonly reported in occlusal development issue. This study aims to determine the correlation between back posture and sagittal jaw position in adult orthodontic patients treated at the dental hospital of Universitas Sumatera Utara.This observational study was conducted on orthodontic patients who had routine orthodontic control between October 2019 and February 2020. The sagittal jaw relationship on pre-treatment cephalometry lateral-based on Steiner analysis was done with OrthoVision software. The back posture that related to cervical, thoracic, and lumbar measurement was performed using scoliometer plastic economy (Baseline®).From 128 patients, aged between 18 and 30 years, we found 72 patients with Class I, 41 patients with Class II, and 15 patients with Class III skeletal malocclusion. There were no significant differences of trunk asymmetry based on sagittal jaw relationship (p = 0.651). Additionally, there was no significant correlation between back posture and sagittal jaw position in Class II and Class III patients (r = 0.112, p > 0.05).In this study, the sagittal jaw relationship had poor correlation to back posture in orthodontic adult patients due to a compensatory mechanism. The presence of temporomandibular dysfunction, sella-nasion-B point, and head posture are specific variables in a particular dento-skeletal type that should be considered in further studies.

The effects of familiarity and gender on spatial representation

This paper reports a study of how familiarity and gender may influence the frames of reference used in memory to represent a real-world regularly shaped environment. Familiar and unfamiliar participants learned the locations of three triads of buildings by walking on a path which encircled each triad. Then they were shown with maps reproducing these triads at five different orientations (from 0° to 180°) and had to judge whether each triad represented correctly the relative positions between the buildings. Results showed that unfamiliar participants performed better when the orientation of triads was closer to the learning perspective (0° and 45°) and corresponded to front rather than to back positions. Instead, familiar participants showed a facilitation for triads oriented along orthogonal axes (0°–180°, 90°) and no difference between front and back positions. These findings suggested that locations of unfamiliar buildings were mentally represented in terms of egocentric frames of reference; instead, allocentric frames of reference defined by the environment were used when the environment was familiar. Finally, males were more accurate and faster than females, and this difference was particularly evident in participants unfamiliar with the environment.

Metamorphosis-Induced Changes in the Coupling of Spinal Thoraco-Lumbar Motor Outputs During Swimming inXenopus laevis

Anuran metamorphosis includes a complete remodeling of the animal's biomechanical apparatus, requiring a corresponding functional reorganization of underlying central neural circuitry. This involves changes that must occur in the coordination between the motor outputs of different spinal segments to harmonize locomotor and postural functions as the limbs grow and the tail regresses. In premetamorphic Xenopus laevis tadpoles, axial motor output drives rostrocaudally propagating segmental myotomal contractions that generate propulsive body undulations. During metamorphosis, the anterior axial musculature of the tadpole progressively evolves into dorsal muscles in the postmetamorphic froglet in which some of these back muscles lose their implicit locomotor function to serve exclusively in postural control in the adult. To understand how locomotor and postural systems interact during locomotion in juvenile Xenopus, we have investigated the coordination between postural back and hindlimb muscle activity during free forward swimming. Axial/dorsal muscles, which contract in bilateral alternation during undulatory swimming in premetamorphic tadpoles, change their left-right coordination to become activated in phase with bilaterally synchronous hindlimb extensions in locomoting juveniles. Based on in vitro electrophysiological experiments as well as specific spinal lesions in vivo, a spinal cord region was delimited in which propriospinal interactions are directly responsible for the coordination between leg and back muscle contractions. Our findings therefore indicate that dynamic postural adjustments during adult Xenopus locomotion are mediated by local intraspinal pathways through which the lumbar generator for hindlimb propulsive kicking provides caudorostral commands to thoracic spinal circuitry controlling the dorsal trunk musculature.

In-Vivo Remote Manipulation of Modified Capsule Endoscopes Using An External Magnetic Field

Background: Remote control of wireless capsule movement would enhance diagnostic accuracy and might allow targeted biopsy. The efficacy and safety of remote manipulation of modified capsule endoscopes using external magnetic fields were assessed in in-vivo survival studies in pigs as part of a European FP6 project called NEMO. Methods: Model and real wireless capsules (Colon & ESO, by Given Imaging Ltd) were modified to include magnetic material aligned to give different field patterns and strength when exposed to an external magnetic field. The magnetic reed switch in the capsule was inactivated to allow continuous real-time viewing. Capsules were placed in the esophagus and stomach of anesthetised pigs (n = 8, 34-78 kg). An external magnet was used to manipulate the capsule with gastroscopic visualisation. Capsules were attached to a thread to allow withdrawal through the cardio-esophageal junction and to measure forces needed to overcome magnetic attraction and peristaltic forces. The ability of a magnetic field to prevent retropulsion of an electrostimulation capsule causing esophageal contraction was tested. Anterior, lateral and posterior external magnet positions and movements were studied with the animals on the back, left lateral and prone positions. Results: An external plate magnet was effective in holding the capsule in specific locations in the esophagus. Swivel motions were particularly effective using small rotations of the external hand-held plate magnet allowing multiple axial panning circular views of the squamo-columnar junction to be obtained. Caudo-cranial axial magnet rotations caused capsules to somersault in the esophagus. Water lubrication enhanced esophageal capsule movement. In the stomach capsules could be manipulated at will throughout the stomach. It was possible but difficult to drive capsules through the cardio-esophageal junction and move capsules into the pylorus but not to release them in the duodenum by removing the magnetic field. Somersaulting and rapid exploration of the stomach was easy. The magnetic field prevented esophageal retropulsion of an electrostimulation capsule. All pigs were well, eating immediately after recovery - esophagus and stomach looked normal at follow up endoscopy. Left lateral position with a posterior hand held magnet was the best for most manipulations. Conclusions: Magnetic capsules could be swivelled, somersaulted, stopped and moved when constrained by an external magnetic field. Such movements were especially effective in enhancing visualization in the esophagus and stomach and were safe when the internal magnetic arrangement was matched to the external magnet and the size of the animal.

Ergonomic Evaluation of the Ambulance Interior to Reduce Paramedic Discomfort and Posture Stress

This study aims to evaluate safety and accessibility of an advanced life support (ALS) ambulance interior. The standard ambulance's interior design is unsatisfactory based on perceived discomfort and postures that constrain paramedics and medical staff, resulting in unsafe treatment of patients, mainly when being transported. Two procedures were used to evaluate performance during a wide range of rescue tasks: a survey, based on questionnaires, interviews, and observation of paramedics performing routine tasks; and upper body and back posture analysis, based on postural considerations. Findings revealed that 74% of the paramedics stated that the location of the paramedic's seat is inefficient while they perform clinical procedures; 94% found the bench uncomfortable; 77% felt that the vertical distance between the bench and the stretcher is too far; and 86% needed to steady themselves when the vehicle was moving. Posture analysis showed that paramedics undergo several nonneutral back postures, including twisted back (>20 degrees) and sitting with back flexion between 20 degrees and 45 degrees. Because the interior of the ALS ambulance was found to be unsatisfactory both to paramedics and patients, alternative design issues are proposed. The suggested practical layout contains four main modifications: (a) replacing the bench with two adjustable paramedic seats, (b) redesigning the medical cabinet for easy access, (c) adding an adjustable folding seat opposite the two new seats, and (d) adding a swiveling base and lifting apparatus that will accommodate the stretcher and enable better accessibility to patients by the paramedic personnel.

Influence of work-related factors and individual characteristics on work ability among Dutch construction workers

The objective of this study was to evaluate the association of individual characteristics, health problems, lifestyle factors, and work-related factors with work ability among Dutch construction workers. In this cross-sectional survey, the study population consisted of 19 507 Dutch construction workers who had participated in a voluntary periodic medical examination in 2005 and for whom complete information on laboratory tests and spirometry was available. The main outcome of the study was work ability, measured by the work ability index. Independent variables consisted of physical and psychosocial work-related factors, individual characteristics, lifestyle factors, and some objective health indicators. Multiple linear and logistic regression models were used to determine the influence of different factors on work ability. Physical workload and, to a less extent, psychosocial factors at work together explained 22% of the variability in work ability. Age, leisure-time physical activity, lung obstruction, and cardiovascular risk profile explained about 10% of the workers' ability to work, but, when adjusted for work-related risk factors, their effects became very small. Awkward back posture, static work postures, repetitive movements, and lack of support at work had the highest influence on work ability. In the construction industry, work-related risk factors were the most important in association with work ability. This finding suggests that interventions aimed at preventing construction workers from dropping out of the workforce should primarily focus on reducing physical and psychosocial load at work.

The Working Postures Among Schoolchildren—A Controlled Intervention Study on the Effects of Newly Designed Workstations

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. 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. 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. 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.

Infant sleep position, head shape concerns, and sleep positioning devices

The Back To Sleep campaign has successfully promoted the use of the supine sleep position for infants, with a corresponding decrease in sudden infant death syndrome death rates around the world. The aim of this study was to survey current infant sleep position practices, concerns about plagiocephaly, and the use of sleep positioning devices. A postal survey of 400 mothers of infants aged 6 weeks to 4 months was carried out in Auckland, New Zealand. Of the 278 (69.5%) respondents, the supine position was usually used in 64.8%, the prone position in 2.9%, with 32.3% using the side position or a combination of side and back positions. Approximately one-third had a concern about their infant's head shape, and 80% described practices to help prevent head deformation. Thirty per cent reported they had changed their infant's sleep position because of head shape concerns. A third of the mothers used some sort of positioning system to maintain the infant's sleep position. Anxieties about plagiocephaly, aspiration of vomit, and poor quality sleep are the main concerns that parents have about sleeping their infants on their backs. Further education is needed to inform mothers about these issues and to alleviate their fears.

Office Ergonomics: Deficiencies in Computer Workstation Design

The objective of this research was to study and identify ergonomic deficiencies in computer workstation design in typical offices. Physical measurements and a questionnaire were used to study 40 workstations. Major ergonomic deficiencies were found in physical design and layout of the workstations, employee postures, work practices, and training. The consequences in terms of user health and other problems were significant. Forty-five percent of the employees used nonadjustable chairs, 48% of computers faced windows, 90% of the employees used computers more than 4 hrs/day, 45% of the employees adopted bent and unsupported back postures, and 20% used office tables for computers. Major problems reported were eyestrain (58%), shoulder pain (45%), back pain (43%), arm pain (35%), wrist pain (30%), and neck pain (30%). These results indicated serious ergonomic deficiencies in office computer workstation design, layout, and usage. Strategies to reduce or eliminate ergonomic deficiencies in computer workstation design were suggested.

The effects of mechanised equipment on physical load among road workers and floor layers in the construction industry

This study describes the impact of the use of mechanised equipment on physical load and workers’ health among road workers and floor layers by comparing the traditional manual work method with frequently occurring scenarios of use of this new equipment. Continuous direct measurements of postures were linked to real-time observations of tasks and external forces applied during manual materials handling. A self-administered questionnaire on musculoskeletal complaints was used. The introduction of a hydraulic clamp or vacuum lift to assist roadmakers while laying a brick-paved road reduced the team's work time in a kneeling/squatting position with 43–52% and frequency of lifting loads of 5–15 kg and above 15 kg with 46–59% and 84–88%, respectively. The introduction of a mixing machine with a pump system during pouring of sand–cement floors reduced the frequency of lifting loads with 66% for 5–15 kg and 15% for over 15 kg, but had no discernable effect on awkward back postures. The use of a silo/truck with automated pump system also reduced the frequency of lifting with 32% and 38%, respectively, but increased the duration in awkward back postures with 13%, primarily due to the hodman partly working as floor layer. Floor layers and hodmen using the mechanical equipment reported a lower prevalence of low back pain in the past 6 months and also less associated sick leave. The introduction of new mechanised equipment resulted in changes in physical load per task within jobs, changes in task distribution within jobs, and changes in work organisation and jobs within a team. The judgement of experts on the impact of new devices on physical load should be corroborated in field studies on the average exposure to physical load per work day and per team. Relevance to industry The study demonstrated the preference of a scenario approach in evaluating the impact of interventions on physical load above the classical analysis of the most strenuous task.

Effects of a Two-School-Year Multifactorial Back Education Program in Elementary Schoolchildren

A quasi-experimental pre/post design. To investigate effects of a 2-school-year multifactorial back education program on back posture knowledge and postural behavior in elementary schoolchildren. Additionally, self-reported back or neck pain and fear-avoidance beliefs were evaluated. Epidemiologic studies report mounting nonspecific back pain prevalence among youngsters, characterized by multifactorial risk factors. Study findings of school-based interventions are promising. Furthermore, biomechanical discomfort is found in the school environment. The study sample included 193 intervention children and 172 controls (baseline, 9-to-11-year-olds). The multifactorial intervention consisted of a back education program and the stimulation of postural dynamism in the class through support and environmental changes. Evaluation consisted of a questionnaire, an observation of postural behavior in the classroom, and an observation of material handling during a movement session. The intervention resulted in increased back posture knowledge (P < 0.001), improved postural behavior during material handling (P < 0.001), and decreased duration of trunk flexion (P < 0.05) and neck torsion (P < 0.05) during lesson time. The intervention did not change fear-avoidance beliefs. There was a trend for decreased pain reports in boys of the intervention group (P < 0.09). The intervention resulted in improved postural aspects related to spinal loading. The long-term effect of improved postural behavior at young age on back pain prevalence later in life is of interest for future research.

Seismic interferometry with a TBM source of transmitted and reflected waves

We discuss the use of autocorrelogram interferometry by using noise from the tunnel-boring machine (TBM). The TBM provides seismic signals/waves while drilling in a tunnel (TSWD). The tunnel geometry, unlike a reverse vertical seismic profile (RVSP) using a drill bit, makes it possible to record the waves reflected from the region between the tunnel face and the projected tunnel exit and those transmitted ahead of the tunnel face. We processed the waves recorded at back positions with respect to the TBM in a manner similar to a RVSP data set obtained by conventional reference-correlation techniques. We processed the waves transmitted ahead of the TBM using autocorrelogram interferometry techniques. Using these wavefields offers advantages over conventional borehole drill-bit vertical seismic profiles (VSPs). The most important advantage is getting reflections from the transmitted (front) wavefield by utilizing Kunetz’s equation and reversed-time traces. The approach also improves the analysis of the transmitted amplitudes. Finally, we improved the deconvolution of the reflected (back) waves by using the transmitted wavefields measured for interferometry purposes. In particular, by using both front (transmitted) and back (reflected) waves, it is possible to deconvolve the signature of the source extended spatially along the tunnel axis. We use a 1D model in which the interfaces are assumed subvertical. We present a case history in which TSWD data were acquired in a tunnel measuring [Formula: see text] long. We compare results from the transmitted reversed-time and back-reflected waves ([Formula: see text]-waves) with those obtained by amplitude analysis and estimation of reflection coefficients. Each approach matches the interpretation of the fractures encountered in the tunnel.