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Motricité, Motricity, Motricidad, Flexion, Bending, Flexión, Homme, Human, Hombre, Membre supérieur, Upper limb, Miembro superior, Mâle, Male, Macho, Pincement, Pinching, Desmoche, Poignet, Wrist, Muñeca, Préhension, Gripping, Prension, Supination, Supinación, Torsion, Torsión, Travailleur, Worker, Trabajador, handgrip, maximum acceptable torques, maximum isometric torque, pinch extension and flexion, screw driving, supination, ulnar deviation, upper extremity, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Psychologie. Psychophysiologie, Psychology. Psychophysiology, Niveaux d'activité. Psychomotricité, Activity levels. Psychomotricity, Activités psychomotrices, Psychomotor activities, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Cognition, Genetics, Génétique, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, and Psychologie, psychopathologie, psychiatrie

Objective: The purpose of the study was to quantify maximum acceptable torques (MATs) in 16 healthy male industrial workers while performing six motions: screw driving clockwise with a 40 mm handle and a 39 mm yoke handle,flexion and extension with a pinch grip, ulnar deviation with a power grip (similar to knife cutting), and a handgrip task (similar to a pliers task). Background: Psychophysical studies on repetitive motions of the wrist and hand were previously reported on women; however, it is not clear how men will psychophysically respond to similar motions. Method: A psychophysical methodology was used in which the participant adjusted the resistance on the handle. Repetition rates for these tasks were 15 and 25 per minute. Participants performed the tasks for 7 hours per day, 5 days per week, and for 12 days. Symptoms were recorded by the subjects at the end of each hour. Results: The mean MATs ranged from 1.15 Nm to 1.88 Nm for screw driving, 2.26 Nm to 3.71 Nm for pinch flexion and extension, 3.88 Nm to 4.07 Nm for ulnar deviation, and 11.47 Nm to 13.98 Nm for the handgrip task.The higher the repetition rate, the lower the MAT. Depending on the type of task and repetition rate, these values represented 15% to 35% (median of 23%) of their maximum isometric torque. Application: Based on aforementioned findings, a table of MATs and derived acceptable forces for six tasks at different percentage capabilities of the male industrial populations is formulated.

Environment, Environnement, Hygiene and public health, epidemiology, occupational medicine, Hygiène et santé publique, épidémiologie, médecine du travail, Toxicology, Toxicologie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Sante publique. Hygiene-medecine du travail, Public health. Hygiene-occupational medicine, Médecine du travail, Occupational medicine, Divers, Miscellaneous, Ergonomie, Ergonomics, Ergonomía, Etude comparative, Comparative study, Estudio comparativo, Exposition professionnelle, Occupational exposure, Exposición profesional, Homme, Human, Hombre, Industrie, Industry, Industria, Manutention, Handling, Manutención, Médecine du travail, Occupational medicine, Medicina ocupacional, Psychophysique, Psychophysics, Psicofísica, Recommandation, Recommendation, Recomendación, Sexe, Sex, Sexo, Travailleur, Worker, Trabajador, Charge physique, Genre, Gender, Género, Carrying, Ergonomic redesign, Lifting and lowering, Manual materials handling guidelines, and Pushing and pulling

Purpose In the year 1991, manual materials handling guidelines were published by Liberty Mutual Research Institute for Safety. In these guidelines, maximum acceptable weights (MAWs) and forces (MAFs) for lifting, lowering, pushing, pulling, and carrying were derived from studies conducted in a 20 year span before the above publication date. The question is whether the present generation of workers has retained the same gender differences and absolute values in psychophysically determined MAWs and MAFs as those reflected in the guideline. Methods Twenty-four female industrial workers performed 20 variations of lifting, lowering, pushing, pulling, and carrying. A psychophysical methodology was used whereby the workers chose a workload they could sustain for 8 h without straining themselves or without becoming unusually tired, weakened, overheated or out of breath. Results In females, MAWs of lifting, lowering, and carrying averaged 53% of the present-day male values, similar to the 55% in the guideline. MAFs of pushing and pulling were 83 and 86% of the present-day male values but slightly higher than the 73 and 78% in the guideline, respectively for initial and sustained forces. Conclusions The similarity of gender differences between the guideline and the present findings was coupled with dramatic decreases in MAWs of lifting, lowering, and carrying. Such decreases may reflect a new psychophysical set point; however, considerations about adjusting existing guidelines on lifting, lowering, and carrying may not be appropriate until additional data from other sources inside and outside the US confirm the present findings.

Education, Éducation, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Démontage, Desassembly, Desmontaje, Ergonomie, Ergonomics, Ergonomía, Etude en laboratoire, Laboratory study, Estudio en laboratorio, Gestion production, Production management, Gestión producción, Homme, Human, Hombre, Montage, Assembly, Montaje, Méthodologie, Methodology, Metodología, Organisation travail, Job engineering, Organización trabajo, Production, Producción, Tâche manuelle, Manual task, Tarea manual, laboratory study, management of production, and work organisation

A study was conducted to investigate the influence of different approaches to arranging the pace and temporal organisation of repetitive assembly and disassembly tasks on both average performance and its variability and to compare assembly and disassembly times derived with psychophysical methods to a more traditional methods-time measurement (MTM) approach. The conditions studied were a traditional assembly line arrangement, where assemblies were started at a pace of 110 MTM (repeated on two occasions), a batch condition, where subjects were required to complete 36 assemblies within the total amount of time allowed at 110, MTM and a psychophysical condition, where subjects were allowed to choose their pace (repeated on two occasions). Overall, the results suggest that the mean time spent working in each cycle (the 'on-time') remained fairly constant across conditions, while the idle 'off-time' in between on-times was shorter and of less varied duration in the more autonomous batch and psychophysical conditions. During the second psychophysical (self-paced) condition, subjects completed a significantly higher number of assemblies than during the 110 MTM line condition. The higher pace was achieved through reduction in mean off-times and the potential implications for musculoskeletal risk are discussed.

Ecology, Ecologie, Environment, Environnement, Pollution, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Pollution, Traitement et pollution des eaux, Water treatment and pollution, Pollution des eaux naturelles, Natural water pollution, Eaux continentales superficielles, Continental surface waters, Analyse risque, Risk analysis, Análisis riesgo, Eau surface, Surface water, Agua superficie, Evaluation risque, Risk assessment, In vitro, Inhalation, Inhalación, Oxyde de titane, Titanium oxide, Titanio óxido, Risque santé, Health hazards, Riesgos contra salud, Réglementation, Regulation, Reglamentación, Santé publique, Public health, Salud pública, Statistique rang, Rank statistic, Estadística rango, Toxicité, Toxicity, Toxicidad, Nanomaterials, environmental risk, human health risk, and risk ranking

As nanomaterials find increased application in commercial and industrial products and processes so too the potential for release of these novel materials into the environment increases. The characteristics of these materials also may result in novel toxicological actions related to their nanoscale, which will have implications on their ecotoxicological and toxicological limits of exposure and eventual regulation. A framework for nanomaterial risk assessment on regulatory, ecotoxicological and toxicological bases developed from recent exposure and toxicity studies is presented. The release of nanoscale TiO2, Ag and CeO2 to the atmosphere and surface waters is assessed against provisional toxicological bench mark doses (BMDs) and critical effect doses (CEDs) developed from best available data. Predicted levels of nanomaterial release to surface waters and the atmosphere resulted in regulatory risk rankings of moderate concern based on worst case provisional regulatory limits. Inhalation and ingestion risk rankings were of very low concern based on the provisional inhalation and ingestion toxicity BMDLs and CEDLs determined for the nanomaterials in question. More toxicological data is needed on nanoscale CeO2 inhalation to develop a true dose response as in vitro cytotoxicity studies yielded an inhalation risk ranking of lower concern. The moderate to high ecotoxicological risk rankings posed by the release of nanoscale TiO2 and Ag to surface waters highlights the need for guidance and restriction on the usage and disposal of commercial products containing nanomaterial. The risk rankings presented in this assessment give a first indication of the relative risks posed by the usage and release of these materials into the environment and indicate what materials require further investigation into their nano-specific toxicological actions. As more nano-relevant toxicity studies are published, end-points and risk levels related to nano-specific toxicity actions may be determined and the provisional BMDLs developed as part of this framework refined, resulting in more confident risk rankings.

Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Ergonomie, Ergonomics, Ergonomía, Femelle, Female, Hembra, Force, Fuerza, Homme, Human, Hombre, Industrie, Industry, Industria, Manutention, Handling, Manutención, Poussée, Thrust, Empujón, Psychophysique, Psychophysics, Psicofísica, Recommandation, Recommendation, Recomendación, Reproductibilité, Reproducibility, Reproductividad, Travail dynamique, Dynamic work, Trabajo dinámico, Travailleur, Worker, Trabajador, Cart pushing, and Manual materials handling

Using psychophysics, the maximum acceptable forces for pushing have been previously developed using a magnetic particle brake (MPB) treadmill at the Liberty Mutual Research Institute for Safety. The objective of this study was to investigate the reproducibility of maximum acceptable initial and sustained forces while performing a pushing task at a frequency of 1 min-1 both on a MPB treadmill and on a high-inertia pushcart. This is important because our pushing guidelines are used extensively as a ergonomic redesign strategy and we would like the information to be as applicable as possible to cart pushing. On two separate days, nineteen female industrial workers performed a 40-min MPB treadmill pushing task and a 2-hr pushcart task, in the context of a larger experiment. During pushing, the subjects were asked to select a workload they could sustain for 8 h without straining themselves or without becoming unusually tired, weakened, overheated or out of breath. The results demonstrated that maximum acceptable initial and sustained forces of pushing determined on the high inertia pushcart were 0.8% and 2.5% lower than the MPB treadmill. The results also show that the maximum acceptable sustained force of the MPB treadmill task was 0.5% higher than the maximum acceptable sustained force of Snook and Ciriello (1991). Overall, the findings confirm that the existing pushing data developed by the Liberty Mutual Research Institute for Safety still provides an accurate estimate of maximal acceptable forces for the selected combination of distance and frequency of push for female industrial workers.

Cognition, Genetics, Génétique, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Pathologie du muscle strié, Striated muscle disease, Músculo estriado patología, Activité professionnelle, Professional activity, Actividad profesional, Charge travail, Workload, Carga trabajo, Chariot industriel, Industrial truck, Carro industrial, Ergonomie, Ergonomics, Ergonomía, Exposition professionnelle, Occupational exposure, Exposición profesional, Femelle, Female, Hembra, Frottement, Friction, Frotamiento, Homme, Human, Hombre, Poussée, Thrust, Empujón, Psychophysiologie, Psychophysiology, Psicofisiología, Surface sol, Ground surface, Superficie suelo, Trouble musculosquelettique, Musculoskeletal disorder, Patología sistema musculoesqueletico, Tâche manuelle, Manual task, and Tarea manual

Objective: The aim of this study was to evaluate psychophysically determined acceptable forces, cardiopulmonary, and calf muscle metabolic responses in 15 workers while they pushed an instrumented cart on two walkways. Background: In addition to the potential for increased musculoskeletal disorders in workers, pushing on various terrains is associated with occurrence of slips and falls at the workplace. Method: Using a psychophysical approach, participants chose the maximum acceptable cart weight they could push without strain on walkways with coefficient of friction equaling 0.68 (plywood) and 0.26 (Teflon-coated.). Then, while participants pushed their psychophysically chosen cart weight for 2 hr on each walkway, horizontal and vertical forces applied on the cart handle and physiological responses were collected. Cardiopulmonary responses were measured using a telemetric metabolic cart. A tissue hemoglobin index (THI) and a tissue oxygenation index (TOI) from the right and left calf muscles were obtained using near-infrared spectroscopy. Results: Participants generated higher horizontal forces (by 26%) on plywood than that on Teflon. Cardiopulmonary and TOI and THI responses were similar between walkways. However, greater ratios of absolute oxygen uptake per force (by 19%) and TOI per force (by 24%) on Teflon were demonstrated in the horizontal direction than on plywood. Conclusions: This increased muscle oxygenation―force ratio, coupled with increased oxygen uptake per force generated on Teflon, might suggest that pushing on the slippery surface results in higher metabolic demand. Application: Findings from the present study will assist in revising previously established acceptable forces and in relating these forces to physiological responses with respect to pushing on different frictional walkways.

Education, Éducation, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Chute, Fall, Caida, Consommation oxygène, Oxygen consumption, Consumo oxígeno, Ergonomie, Ergonomics, Ergonomía, Force musculaire, Muscle strength, Fuerza muscular, Glissement, Slip, Deslizamiento, Homme, Human, Hombre, Muscle strié, Striated muscle, Músculo estriado, cart pushing, muscle blood volume, near-infrared spectroscopy, oxygen uptake, slips and falls, and tissue oxygenation index

Pushing is an important materials handling activity in many occupations; however, pushing-related physiological investigations are still in infancy. The purpose was to evaluate maximum acceptable forces and physiological responses while pushing on: treadmill (TREAD); plywood floor (PLY); and Teflon floor (TEF). Acceptable forces, cardiopulmonary and calf muscle oxygenation and blood volume responses were collected simultaneously while 12 men (age 39 ± 13 years; height 178 ± 6 cm; and body mass 91.5 ± 16 kg) pushed for 2 h on each surface at their psychophysical workload. Participants selected higher forces on the PLY, resulting in higher pulmonary oxygen uptake compared to that of TEF (by ∼ 9%) and TREAD (by ∼ 18%). Pushing on the TEF demonstrated 50-56% lower blood volume changes and 1.5―1.8 times more oxygenation-force ratio than that for other surfaces. It is concluded that, to avoid a potential slip, participants were conservative in selecting acceptable forces to push on the slippery TEF. Part of this compensatory strategy on the TEF resulted in less muscle activity and, therefore, less demand for oxygen delivery to the calf muscle than for other surfaces. The present findings of significant force- and physiological-related differences in treadmill vs. high inertia pushcart clearly demonstrate that pushing experiments are essential to evaluate functional abilities of the workers.

Education, Éducation, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Consommation oxygène, Oxygen consumption, Consumo oxígeno, Ergonomie, Ergonomics, Ergonomía, Homme, Human, Hombre, Manutention, Handling, Manutención, Prédiction, Prediction, Predicción, materials handling, oxygen consumption, and work physiology

An experiment was conducted to develop models to predict oxygen consumption of males and females engaged in common materials handling tasks including lifting, lowering, pushing, pulling, (de)palletising and combination tasks involving lifting or lowering a box and carrying it a set distance and lifting or lowering it to the destination. Nineteen male and 19 female subjects participated in the study. A psychophysical approach was used to set load limits for individual subjects for the oxygen consumption protocol. The 8398 oxygen consumption values collected were entered into the initial regression analyses and 168 potential outliers were removed before the final models were run. In addition to relevant task variables, body weight was a significant predictor variable in all models. The r2 values for the final models ranged from 0.54 to 0.82 and the root mean square errors ranged from 90.2 ml to 294.8 ml.

Education, Éducation, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Activité manuelle, Manual activity, Actividad manual, Ergonomie, Ergonomics, Ergonomía, Force, Fuerza, Homme, Human, Hombre, Industrie, Industry, Industria, Manutention, Handling, Manutención, Matériel manutention, Handling equipment, Instalaciones manipulación, Psychophysique, Psychophysics, Psicofísica, Recommandation, Recommendation, Recomendación, Rétrospective, Retrospective, Retrospectiva, Travailleur, Worker, Trabajador, ergonomic redesign, manual materials handling, maximum acceptable weight and forces, and psychophysics

The most frequent and expensive cause of compensable workplace injuries loss is manual material handling (MMH). In an attempt to minimise these losses, refinement of existing MMH guidelines is a component of redesigning high risk MMH jobs. In the development of the present MMH 1991 guidelines (Snook and Ciriello 1991), maximum acceptable weights (MAWs) and forces (MAFs) were derived from studies conducted in a 21 year time span before the above publication date. The question arises whether the present generation of workers have the same psychophysically determined weights and forces as those reflected in the guidelines. Therefore, the present study investigated whether secular changes had occurred in key MMH tasks in trials performed by present day local industrial workers. A total of 23 male industrial workers performed 20 variations of lifting, lowering, pushing, pulling and carrying tasks. A psychophysical methodology, identical to that of the authors' previous experiments, was used whereby the subjects were asked to select a workload they could sustain for 8 h 'without straining themselves or without becoming unusually tired, weakened, overheated or out of breath'. The results revealed that MAWs of lifting, lowering and carrying averaged 69% of the guideline values. MAFs of pushing and pulling showed less of a drop, averaging 82% and 94% respectively for initial and sustained forces. The results also indicated that the effects of the variables frequency, height, lifting vs. lowering, pushing vs. pulling were similar to earlier reported results, even though the absolute weights or forces were lower. It was concluded that consideration to change existing guidelines, reflecting this new psychophysical set point, may be appropriate if these significant performance decreases are confirmed in other locations, with greater subject numbers, and by other investigators.

Education, Éducation, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, Psychologie, psychopathologie, psychiatrie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Physiologie humaine appliquee a l'etude des populations et des conditions de vie. Ecophysiologie humaine, Human physiology applied to population studies and life conditions. Human ecophysiology, Physiologie appliquée, Applied physiology, Ergonomie. Poste de travail. Physiologie du travail, Ergonomics. Work place. Occupational physiology, Activité manuelle, Manual activity, Actividad manual, Biomécanique, Biomechanics, Biomecánica, Découpage, Cutting, Troquelado, Ergonomie, Ergonomics, Ergonomía, Force, Fuerza, Homme, Human, Hombre, Poignet, Wrist, Muñeca, Poste travail, Workplace layout, Puesto trabajo, Préhension, Gripping, Prension, Simulation, Simulación, Usine viande, Meat processing plant, Fabrica carne, Cutting moment, Grip force, Knife, Meatpacking, Workstation, and Wrist deviation

The purpose of the study was to investigate factors related to force and postural exposure during a simulated meat cutting task. The hypothesis was that workstation, tool and task variables would affect the dependent kinetic variables of gripping force, cutting moment and the dependent kinematic variables of elbow elevation and wrist angular displacement in the flexion/extension and radial/ulnar deviation planes. To evaluate this hypothesis a 3 × 3 × 2 × 2 × (surface orientation by surface height by blade angle by cut complexity by work pace) within-subject factorial design was conducted with 12 participants. The results indicated that the variables can act and interact to modify the kinematics and kinetics of a cutting task. Participants used greater grip force and cutting moment when working at a pace based on productivity. The interactions of the work surface height and orientation indicated that the use of an adjustable workstation could minimize wrist deviation from neutral and improve shoulder posture during cutting operations. Angling the knife blade also interacted with workstation variables to improve wrist and upper extremity posture, but this benefit must be weighed against the potential for small increases in force exposure.