An equation to predict maximum acceptable loads for repetitive tasks based on duty cycle: evaluation with lifting and lowering tasks

Recently, an equation was developed to predict maximal acceptable effort (MAE) for repetitive tasks based on the product of task frequency and effort duration (ie. duty cycle). This equation has been shown to closely match data from psychophysical studies of the upper extremities. In the current paper, the applicability of this equation was tested on lifting and lowering data from Snook and Ciriello (1991) and was found to fit closely, even at very low duty cycles.     

MultipLa--a tool for the combined overall estimation of various types of manual handling tasks

In the 1990ies the German Federal Institute for Occupational Safety and Health (FIOSH) published "Key Indicator Methods" (KIM) for the evaluation of manual material handling tasks. These methods served as a national German implementation of the EU Manual Handling Directive (90/269/EEC). These methods allow the evaluation of individual handling tasks like lifting or pushing. KIM tools do not allow evaluating complex handling tasks like a combined lifting and pushing task. With respect to the needs at shop floor level (e.g. logistics), MultipLa tries to bridge that gap by means of an EXCEL based worksheet using the KIM philosophy. In the past several algorithms for a risk assessment had been developed. At the moment MultipLa is in a test phase at several automotive OEMs.     

Occupational lifting tasks as a risk factor in low back pain: a case-control study in a Mexican population

The objective of this study was to quantify and assess whether lifting tasks in the workplace are a risk factor in lumbar spondyloarthrosis etiology. A case-control study was performed with 231 workers, 18-55 years old, insured by the Mexican Social Security Institute (IMSS, according to its designation in Spanish). A multivariate analysis using conditional logistical regression showed that lifting tasks, combined with driving tasks, are associated with this illness (OR = 7.3; 95% CI 1.7-31.4). The daily frequency of lifting as it interacts with work as a driver resulted in a greater risk (OR = 10.4; 95% CI 2.0-52.5). The load weight, daily task-hours and cumulative time showed a dose-response relationship. The attributable risk for lifting tasks was 0.83, suggesting that 83% of lumbar spondyloarthrosis development could be prevented if risk factors were eliminated by ergonomic redesign of the task.     

Product evaluation based in the association between intuition and tasks

This paper explores the importance of researching the intuitiveness in the product use. It approaches the intuitiveness influence for users that already had a visual experience of the product. Finally, it is suggested the use of a table that relates the tasks performed while using a product, the features for an intuitive use and the performance metric "task success".     

Gender involvement in manual material handling (mmh) tasks in agriculture and technology intervention to mitigate the resulting musculoskeletal disorders

The lifting and carrying of loads in agriculture on small landholdings are unavoidable. Rural communities often lack access to appropriate technologies which may result in various health hazards. The objective was to study gender participation in agricultural activities involving manual material handling tasks, to assess MSDs experienced in various MMH tasks and to evaluate traditional method and designed technology. The study was conducted on 100 agricultural workers. Data on gender participation in MMH tasks in household, animal husbandry and agriculture and resulting MSDs was gathered. Pre and post assessment of technology intervention was done for NIOSH Lifting Index, QEC, and RPE. The results revealed greater susceptibility of females to musculoskeletal problems in most of the household and animal husbandry tasks. The hand trucks designed were pushing type with power grasp handle. The respondents were advised to carry 5 kg of weight per lift instead of lifting more weight in one lift/minute while filling the hand truck. By decreasing the weight and increasing the number of lifts per minute the respondents were seen falling in green zone indicating significant reduction in NIOSH lifting index. QEC scores concluded that for filling the hand truck 5 kg of weight should be carried to keep the exposure level low.     

The effects of functional limitations on soldier common tasks

This paper describes the findings associated with the ability of an individual to perform the United States Army's Common Soldier Tasks of: "Maintaining an M16-Series Rifle" , "Protect Yourself from Chemical, Biological, Radiological, and Nuclear (CBRN) Injury or Contamination with Mission-Oriented Protective Posture (MOPP) Gear", and "Protect Yourself from Chemical and Biological (CB) Contamination Using Your Assigned Protective Mask." The analysis was conducted using data compiled from videos of a Soldier performing the given tasks at Walter Reed Army Medical Center. The findings reflect the opinions of researchers in identifying potential elements, which impose abnormal, irregular, and/or extraneous effort when performing the tasks as outlined in STP-21-1-SMCT - Soldier's Manual of Common Tasks: Skill Level I.     

The evaluation of team lifting on physical work demands and workload in ironworkers

Lifting and carrying heavy loads occur frequently among ironworkers and result in high prevalence and incidence rates of low back complaints, injuries and work-disability. From a health perspective, little information is available on the effect of team lifting on work demands and workload. Therefore, the objective of this study was to compare the effects of team lifting of maximally 50 kg by two ironworkers (T50) with team lifting of maximally 100 kg by four ironworkers (T100). This study combined a field and laboratory study with the following outcome measures: duration and frequency of tasks and activities, energetic workload, perceived discomfort and maximal compression forces (Fc peak) on the low back. The physical work demands and workload of an individual iron worker during manual handling of rebar materials of 100 kg with four workers did not differ from the manual handling of rebar materials of 50 kg with two workers, with the exception of low back discomfort and Fc peak. The biomechanical workload of the low back exceeded for both T50 and T100 the NIOSH threshold limit of 3400N. Therefore, mechanical transport or other effective design solutions should be considered to reduce the biomechanical workload of the low back and the accompanying health risks among iron workers.     

Test-retest reliability on nine tasks of the Physical Work Performance Evaluation

The Physical Work Performance Evaluation (PWPE) is one of many functional capacity evaluations (FCEs) currently available to assist with determining injured workers' physical potential to return to work. Previous research has explored interrater reliability, construct and predictive validity of the PWPE. This research examined test-retest reliability on a sample of 24 clients with stable physical injuries who were participating in vocational rehabilitation. Nine of the 21 main tasks of the PWPE were evaluated: lifting floor to waist, bilateral carrying, pushing, sitting, standing, kneeling, stair climbing, repetitive squatting and walking. Kappa scores ranged from 0.19 (error) to 0.77 and percent agreement from 66.7% to 87.5%. The results for kneeling, lifting floor to waist, bilateral carrying and pushing tasks suggest substantial test-retest reliability with moderate reliability also suggested for the standing and repetitive squatting tasks. Self-limiting behavior and alterations in pain scores, position adjustments and movement deviations are seen to be the main contributors to affect scoring between the first and second tests.     

Effects of critical incident tasks on the intercultural competence of English non-majors

ABSTRACT

In this internationalised world, graduate employability in terms of intercultural communication skills needs to be taken into account in higher education. The present study aims to explore the effects of critical incident task instruction on English non-majored undergraduates’ intercultural competence. One group of students received ten weeks of instruction with one critical incident task per week and another group received standard English classes. Data were collected from the students’ pre- and post-test. The results showed a significant and strong effect of the intervention with critical incident tasks. Implications for educational practice are presented for further teaching with critical incident tasks.     

The effect of visualization method on the performance of simulated microsurgery tasks

The operating microscopes may be a significant cause of fatigue and discomfort in surgeons. The need for the microscope to be placed over the operating field forces surgeons to remain at the microscope's eyepieces at an uncomfortable posture for the entirety of the surgery. This study compared the effects on microsurgical task performance for four visualization methods: a monocular microscope, a binocular microscope, a three-dimensional (3D) flat-panel television display and a two-dimensional (2D) flat-panel television display. Eleven subjects each performed two microsurgical tasks and their performance was documented by video camera. The statistical analysis performed indicated utilization of the microscope as a visualization method increased subject performance. No significant difference in performance between the 2D and stereoscopic visualization methods.     

Assessing political participation on the Internet in contemporary China

Drawing on the resource model of political participation, this study examines the ways in which various resources, including money, computer and Internet access, Internet skills, and civic skills predict Chinese citizens’ political participation online. The results showed that income was a significant predictor of online political participation regardless of whether it was by using the Internet to contact governmental officials, monitoring public policies online, or participating in online protests. Civic skills also consistently predicted the three forms of online political participation. Computer and Internet access, as well as Internet skills, were significant predictors of some forms of online political participation, but not all of them. Political interest positively moderated the association between income and each of the three dependent variables. The theoretical and empirical implications of these results are discussed.     

A review of research on techniques for lifting low-lying objects: 1. Criteria for evaluation

Advice and training on techniques for lifting is frequently provided. The choice of which technique to use should be based on the evidence available on a number of criteria. Important criteria include: psychophysical, physiological, biomechanical, psychological, performance and clinical. However few professionals have the time to read all the original research required to understand the limitations of the available criteria. The purpose of this paper was to present an accessible synthesis of the criteria used to choose a specific technique. Each criterion is described and its validity discussed to provide the reader with a better understanding of the criteria, and thus the evidence available.     

The effects of back belts and load on selected lifting kinematics during a simulated patient transfer

This study used two dimensional biomechanical analysis to examine the effects of back belts and lifting load on selected lifting kinematics during a simulated patient transfer. A human manikin placed in a sitting position was attached to a customized lifting apparatus which controlled the lifting load and direction of the manikin. Eighteen female participants, between the age of 21 and 27, completed six lifts (sit to stand transfers) of the manikin. Three lifts were completed at the 30 lb load condition (no belt, belt 1 and belt 2) and three lifts were completed at the 50 lb load condition (no belt, belt 1 and belt 2). A doubly two way ANOVA found a significant main effect for the belt condition, F(12,6)=10.06, P=0.002. There was no significant effect for load and no interaction existed between belt and load. The results revealed a significant decrease in trunk flexion when participants wore the wider (nine inch) belt during the 30~lb lifts when compared to the no belt trials. No significant differences were found in trunk flexion means with the narrower width (six inch) belt. No significant differences were found in trunk spinal flexion with either belt condition during the 50 lb lifts. There were no significant differences found in either of the belts in the means of lifting time, knee flexion, elbow flexion, forward displacement of the lifter's center of mass, and the lifter's maximum center of mass velocity. The results suggest that wider back belts may be more effective at reducing spinal flexion during patient lifting under moderate load conditions when compared to narrower back belts and to no-belted controls.     

基于市民角度的城市环境影响及对策研究

伴随着我国经济实力的稳步提高．全国各地的城市化进程进入新一轮高潮。虽然经济的高速发展需要高效、合理的城市建设．但一些盲目、不切实际的城市建设势必会对以后的城市发展带来隐患。我国现阶段的城市建设就存在这样一种跟风逐流的问题．高楼大厦、广场绿地的统一模式不仅带来了城市间的单调雷同．也造成了原有城市特色的不断消失。     

Effects of feedback and educational training on maximization in choice tasks: experimental-game evidence

Compelling evidence exists that behavior is inconsistent with the assumptions of expected-utility maximization. However, if learning occurs, then maximization may take place asymptotically (albeit slowly). But a series of experiments by Herrnstein and his associates show that under very general conditions, feedback and experience lead people away from maximization, rather than toward it—a phenomenon termed “melioration.” In this paper, we describe two experiments designed to explore the interactions among cognitive skills, maximization, and feedback. Using students of Economics and Industrial Engineering, we show that clear constructive feedback is a partial substitute for cognitive skills in decision-making.     

Comparison of a simulated versus work environment lifting task on L5/S1 compression forces

Since a patient's ability to perform simulated work activities guides return-to-work decisions, a significant question to address is whether the simulated work environment accurately reflects the actual work environment. Work hardening programs have been used extensively as a method of rehabilitating workers to return to their pre-injury functioning levels. Re-training workers to lift boxes is a common method used to simulate the work environment. Although very few boxes used in the real work environment have handles, boxes with handles are often used in the simulated work environment. The difference in compression forces at the L5/S1 joint while lifting boxes with and without handles was investigated. The Lift Trak Motion Analysis system was used to estimate lumbar isometric compression forces exerted while lifting a 20-pound (9.07-kg) box. The results indicated that estimates of compression forces when lifting a box without handles were significantly different (p < 0.01) than when lifting the same box with handles. Based on these results, it is recommended that work hardening professionals carefully re-evaluate the simulated work environments currently being used for treatment.     

Assessing the effect of changes in housing costs on food insecurity

In this paper, we examine whether changes in housing costs lead to changes in rates of food insecurity for economically vulnerable families. We use data on a national, longitudinal sample of young families with children merged with data on housing (rental) costs at the state, metropolitan statistical area, and county levels (2001–2003). Focusing on families near or at the poverty level and using household fixed effects, we demonstrate that increased housing costs over this time period have indeed increased rates of food insecurity. Our preferred results suggest that a $500 increase in yearly rental costs is associated with nearly a 3% increase in food-insecurity rates (10% relative increase). We show that our measure of rental costs seems to affect only the food insecurity of renters and not that of poor low-income home owners, suggesting the validity of our methods and robustness of the findings. We also look at selected subgroups (e.g., food stamp recipients, individuals receiving housing subsidies) and find few differences in the effects of housing cost increases on food insecurity.