Identification of Construction Cumulative Trauma Disorders: A Machine Vision Approach

Simultaneous trunk kinematic variables of industrial workers performing jobs with varying degrees of low back disorder risk were quantified, by using a three-dimensional electrogoniometer. To assess the distinguishing patterns of simultaneous multidimensional (complex) motion parameters of workers performing manual material handling jobs with varying degrees of low back disorder risk. There is significant epidemiologic and biomechanical evidence that implicates simultaneously occurring or combined motions and loading as important risk factors follow back disorder. However, the specific levels or magnitudes and patterns of these complex motions at which risk of low back disorder is increased are still unknown. An industrial database of 126 workers and jobs was used to quantify the complex trunk motions of groups with varying degrees of low back disorder risk. Three groups, low-, medium-, and high-risk, were defined on the basis of retrospective injury records of the corresponding jobs. The jobs were further classified into five cells of weight-lift rate combinations. Within each weight-lift rate cell, the three-dimensional trunk motion patterns of workers were analyzed. Bivariate distributions and cumulative distribution functions were used to compare the simultaneous occurrence of complex dynamic motions among risk groups. High- and medium-risk groups exhibited complex trunk motion patterns involving high magnitudes of combined velocities, especially at extreme sagittal flexion; whereas the low-risk group did not. Postural trunk information alone did not provide a consistent pattern of distinguishing among risk groups. Elevated levels of complex simultaneous velocity patterns were unique to groups with increased low back disorder risk. Knowledge of these complex trunk velocity patterns in combination with key workplace factors provides a more sensitive means for identifying low back disorder occupational risk factors than does mere postural information.

Disturbance and recovery of trunk mechanical and neuromuscular behaviours following repetitive lifting: influences of flexion angle and lift rate on creep-induced effects

Dose-Response Relationship Between Moderate to Vigorous Physical Activity and Risk of Back Disorders: A Large-Scale Accelerometry Study.

The occupational exposure limits of different risk factors for development of low back disorders (LBDs) have not yet been established. One of the main problems in setting such guidelines is the limited understanding of how different risk factors for LBDs interact in causing injury, since the nature and mechanism of these disorders are relatively unknown phenomena. Industrial ergonomists' role becomes further complicated because the potential risk factors that may contribute towards the onset of LBDs interact in a complex manner, which makes it difficult to discriminate in detail among the jobs that place workers at high or low risk of LBDs. The purpose of this paper was to develop a comparative study between predictions based on the neural network-based model proposed by Zurada, Karwowski & Marras (1997) and a linear discriminant analysis model, for making predictions about industrial jobs according to their potential risk of low back disorders due to workplace design. The results obtained through applying the discriminant analysis-based model proved that it is as effective as the neural network-based model. Moreover, the discriminant analysis-based model proved to be more advantageous regarding cost and time savings for future data gathering.

The effectiveness of commonly used lifting assessment methods to identify industrial jobs associated with elevated risk of low-back disorders

Adoption of the stooped posture in the workplace is widespread throughout the world in agriculture, construction, and mining. This type of posture has been established as a risk factor for developing low back disorders (LBDs). The purpose of this study is to evaluate a personal weight transfer device as a possible intervention to reduce the load on the lumbar spine, thereby reducing the risk of developing LBDs. Eighteen healthy subjects performed stooped posture tasks in a laboratory study designed to simulate harvesting of low-growing crops. Results showed that when wearing the device in the static stooped posture, biceps femoris activity was reduced by 17%, lumbar flexion was reduced by 12%, ankle plantar-flexion increased by 5%, and the lumbar erector spinae of those subjects who did not experience flexion-relaxation of the erector spinae was reduced by 26%. Hip and knee flexion were not significantly altered. Therefore, the device may be beneficial for those with existing LBDs, and who use the stooped posture routinely.

This study examined the effects of waste container handling on surface electromyographic activity of the erector spinae, infraspinatus and upper trapezius muscles, trunk kinematics (position, velocity and acceleration) measured in three planes (lateral, sagittal and transverse), spinal loading at the L5/S1 region and low back disorder (LBD) risk. Eleven field technicians at the Lawrence Livermore National Laboratory (LLNL) were asked to manipulate 30 and 55 gallon waste drums and carry a 5 gallon carboys in their workplace. Results showed that there was a statistically significant difference in muscle load on the erector spinae during drum handling activities. Loading and unloading the 55-gallon drums required more force from all muscle groups than the 35-gallon drums. Muscle peak load did not show a significant difference between 35 and 55 gallon drum rolling. For carboy transport, peak muscle activity is greater for all muscle groups with the two carboy carry. The calculated LBD risk also recognized the same activities as being most “at risk.” This data was used by the participatory team to focus their interventions and determine handling limits.

The influence of individual low back health status on workplace trunk kinematics and risk of low back disorder

Effect of a personal weight transfer device on muscle activities and joint flexions in the stooped posture

Low back disorders (LBDs) continue to be a major occupational health problem facing the agricultural workforce. Working in a flexed or stooped posture is one of several workplace factors associated with occupationally related LBDs and is highly prevalent in many agricultural tasks. The purpose of this article is to evaluate the role of stooped work in the problem of LBDs among agricultural workers by examining the epidemiological literature, evaluating the scope of stooped work in agriculture, and examining current and potential intervention approaches. The literature review indicates that the prevalence of LBDs in agriculture worldwide is considerably high and substantially reported. Workers who are exposed to stooped work in agriculture are estimated to be in the 100s of millions worldwide. However, stooped work has not been specifically investigated as an independent LBD risk factor. Plausible biomechanical and physiological mechanisms of how stooped work may lead to damage to the spinal structures are discussed, and this complements the epidemiological evidence of high prevalence of LBDs in agriculture. However, this study also identifies the need to conduct more thorough epidemiological studies that utilize accurate quantitative exposure and outcome assessment techniques for developing more appropriate dose-response relationships in agricultural stooped work. This will provide better means for evaluating current and future interventions for jobs involving stooped work. Various intervention approaches are summarized to control and abate stooped work in agriculture; however, it must be emphasized that any development of ergonomic interventions for stooped work in agriculture must incorporate a participatory ergonomics approach that integrates the opinions and concerns of workers, managers, and ergonomists.

Many of those working on construction sites are exposed to demanding work loads; construction workers lift and carry heavy materials and work in awkward postures. Occupational injuries and accidents due to poor ergonomics are more common in the construction industry and many times lead to human tragedies, disrupt construction processes and adversely affect the cost, productivity, and the reputation of the construction industry. In Sweden, it is reported that concrete workers have the highest relative work-related musculoskeletal injury frequency. Therefore, the use of ergonomic production methods to prevent this can have a significant human, social and financial impact. Research introduced here presents a case study of comparative analyses of ergonomic situations for concrete workers performing concrete casting processes. Three different ergonomic risk assessment methods were used to assess the physical strain, hand-arm vibration and noise affects risks involved in concrete casting work tasks. The combination of technical and managerial factors results in a system where workers are as efficient and safe as possible during their work tasks, and thus, makes the construction work environment sustainable. The aim of our research is to find practical methods to evaluate and compare two different concrete casting methods from an ergonomic perspective. The focus is on the production of cast-in-place concrete bridge constructions where the traditional concrete casting method is compared with the SCC (Self-Compacting concrete) casting method. To be able to identify work-related musculoskeletal injury risks due to concrete casting work tasks, QEC (Quick Exposure Check for musculoskeletal risks), PLIBEL (Checklist for identification for Ergonomics Hazards) and ErgoSAM (Ergonomic production technology method) methods were used. Ergonomic risks analysis methods QEC, PLIBEL and ErgoSAM have all shown capabilities to evaluate construction work activities and thus determine whether a construction work activity constitutes a musculoskeletal risk to the worker or not before any ergonomic intervention is introduced. As a result the present ergonomic risks emanating from work methods used in the traditional concrete placing can be significantly reduced with the use of self-compacting concrete (SCC) that eliminates awkward work postures, noise and hand arm vibration, thereby reducing if not eliminating musculoskeletal injuries among concrete workers during their concrete casting work tasks.

Asymmetric low back loading in asymmetric lifting movements is not prevented by pelvic twist

A new approach to applying feedforward neural networks to the prediction of musculoskeletal disorder risk

Objective To investigate the impact of tension and laxity in the sacroiliac interosseous ligament on lumbar spine displacement and force response in vibration environments. Methods A finite element model of the lumbar-pelvis, previously crafted and rigorously validated, was used to simulate ligament tension and laxity by adjusting the elastic modulus of the SIL under a sinusoidal vertical load of ±40 N at 5 Hz. Comparisons of lumbar spine horizontal and axial displacements as well as annulus fibrous stress, nucleus pulposus pressure, and facet joint force were performed, respectively. Results With the elastic modulus of the SIL varying by +50, −50, and −90%, the maximum vibration amplitude changed by +20.00, −175.00, and −627.27% for lumbar horizontal displacement, +30.00, −157.14, and −627.22% for lumbar axial displacements, +5.88, −19.35, and −245.16% for annulus fibrous stress, +10.00, −25.00, and −157.14% for nucleus pulposus pressure, as well as +6.54, −20.13, and −255.37% for facet joint force, respectively. Conclusion In contrast to static environments, large laxity of the SILs not only diminishes lumbar spine stability in vibrational settings but also significantly amplifies dynamic loads, thereby heightening the risk of lumbar spine vibratory injuries and low back pain disorders.

Transportation is very important. Without it, there would be no life in the city and life is essential for the survival of modern society. As the population increased, the need for various means of transportation became critical. One of the reliable means of transportation is the use of minibus. As reliable as minibus seems, little attention has been given to ergonomic interaction between it and its users in Okitipupa, Nigeria. Therefore, this study focuses on the anthropometric perspective and ergonomic evaluation of minibus as a means of public transportation in Okitipupa, Nigeria. 120 commuters (60 males and 60 females) participated in the study. Seat dimensions such as seat height, seat depth, seat width, backrest height and clearance height were collected. These dimensions were compared with popliteal height, buttock-popliteal length, hip width, sitting-shoulder height and sitting stature respectively using match equations. Commuters’ responses and the outcome of the match equations analysis were in reasonable agreement. For example, about 95% commuters complained of leg pain due to inappropriate seat height while the seat height was inappropriate for virtually all the commuters from match equations analysis. The study seems to suggest that the anthropometric dimensions (AD) of the intended users were not considered in the design of the minibus. However, commuters using minibus which is not compatible with their AD are liable to future health issues due to repetitive CTDs (cumulative trauma disorders) and awkward postures. AD of the intended users, if considered, may help to reduce the CTDs.