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.     

Postural assessment of school children: an input for the design of furniture

During the last decades of the previous century, school desks with a tilt top have disappeared. The chairs have been designed for sitting upright, with the hip, knees and ankles all at right angles. However, the erect posture cannot be maintained for more than one or two minutes, after which it will result in fatigue, discomfort or poor posture. The main aim of project is to identify the type of furniture that most effectively contribute to adequate neck and back postures of the school children, by carrying out a postural analysis of a sample of school pupils when using three different types of furniture. The postures adopted by school pupils were monitored by video during several activities, such as reading, writing and painting tasks, copying from a blackboard and listening the teacher. Additionally, the characteristics of the adopted postures were assessed by registering the head tilt, flexion of the neck, trunk and hips position. All these aspects were classified and the results were recorded for future analysis. The obtained results seem to point out that the use of a school desk with a tilted table surface resulted in a reduction in trunk and neck flexion, preserving the natural lordosis in the lumbar and cervical regions. Accordingly, it can be concluded that there are alternatives to consider in the furniture design in order to eliminate tensions and, consequently, to improve children's wellbeing.     

Eye- and neck/shoulder-discomfort during visually demanding experimental near work

Frequent use of digital information technology has an impact on eye- and neck/shoulder-discomfort. Studies with cross sectional and intervention design indicate an association between the two symptom categories. Still, whether visually demanding near work, per se, contributes to increased neck/shoulder discomfort remains a question of debate. The aim of this laboratory study was to assess if visually demanding experimental near work affects eye- and neck/shoulder-discomfort when the posture was adjusted for comfort and no movements were allowed. Thirty-three healthy subjects performed a visually demanding computer screen task (viewing task) under four different optical lens conditions: binocular -3.5 D and monocular -3.5 D, +3.5 D and ± 0 D. During the experiment subjects were seated in an office chair (with neck support) that was individually adjusted for comfort. At baseline and after each viewing task, subjects reported their perceived eye- and neck/shoulder discomfort on Borg's CR-10 scale. Results show a significant increase of eye discomfort between baseline and the first viewing task, and a significant increase in neck/shoulder discomfort from baseline throughout the first three viewing tasks. Further analysis is required to determent whether the neck/shoulder discomfort was induced by the demanding near work or the static posture, or a combination.     

Notebook computer use with different monitor tilt angle: effects on posture, muscle activity and discomfort of neck pain users

This study aimed to evaluate the posture, muscle activities, and self reported discomforts of neck pain notebook computer users on three monitor tilt conditions: 100°, 115°, and 130°. Six subjects were recruited in this study to completed typing tasks. Results showed subjects have a trend to show the forward head posture in the condition that monitor was set at 100°, and the significant less neck and shoulder discomfort were noted in the condition that monitor was set at 130°. These result suggested neck pain notebook user to set their monitor tilt angle at 130°.     

Ergonomic evaluation in a values transportation company in Venezuela

The objective was to analyze the work activity and identify risk factors that could account for musculoskeletal disorders in the upper extremities, shoulder and neck of workers of a transport values company in Venezuela. The methods used were: collective interview, tasks observation, evaluation of posture with RULA method and evaluation of repetitive motions with the OCRA method. Five workstations were evaluated. Main problem perceived by workers was: exposure to chemical and biological hazards when handling paper money and coins; inadequate chairs and close supervision. The postures level risk was 1 or 2 for the RULA scale. Only two workstations showed ligth and medium risk level by OCRA method. Conclusion: The factors identified that could explain the musculoskeletal changes were: wrist repetitive flexion and extension, shoulder elevation, lifting weight above shoulder height, elbow repetitive flexion and extension, neck flexion, extended work journey, work overload, high responsibility and strict supervision by a video camera.     

Postural analysis of eight university student wheelchair users when performing written exercises in their classroom: a case study in Santiago de Cali, Colombia

In students with physical disabilities, the more energy and time required and invested into finding a good posture, the longer the learning process takes. For this reason, the objective of this study was to characterize the posture in the act of writing of wheelchair users in a classroom. Eight students, (three women) aged 18-40, of some of the main universities of the city of Santiago de Cali participated. An observational field study filming of approximately 10 minutes was done while they took notes in their classes. Posture of the head, trunk, and upper extremities was analyzed with respect to its axis and the type of movement in each joint. The postures were classified depending on the location of support surface finding five different postures in the eight students. In these five postures some biomechanical risk factors, usually present in wheelchair users, are increased when they are associated with those postures. Those associated risk factors are: possible disc spine deformation, muscular stress and causing of pressure ulcer. In conclusion, in four of these five postures a poor interaction among person, task and work desk was observed. Therefore, seven of the eight students in this study were found to have a posture that could be considered risky.     

Adoption of ergonomic features in a new reach truck cabin design--a usability study

The task of handling reach trucks frequently involves poor working postures. The location of the steering wheel in most reach trucks is in front of the operator which requires the drivers to bend forward and stretch their hands for holding onto the steering wheel. To overcome visibility restrictions, this posture is aggravated by twisting and bending their torso sideways. This paper presents a usability study which was conducted to compare adoption of ergonomic features in a new reach truck cabin with the way they were intended to be employed for improving physical working conditions. Participants drove the reach truck on a test track performing tasks of varying complexity. Video recordings were utilized to facilitate the observations. The results indicate that improved ergonomics features of the reach truck are not used as intended. The test subjects instead adopted postures that they were accustomed to when driving common reach trucks. The possible contributing factors to this posture regression are discussed. The procedure used in this study is recommended for the companies to determine the effectiveness and adoption of ergonomics solutions.     

Asperger’s Syndrome and the Decoding of Boredom,Interest, and Disagreement from Body Posture

Twenty Asperger’s Syndrome (AS) participants were compared with 20 matched neurotypical controls in their decoding of postural cues of boredom, interest, and disagreement. On a nonverbal matching task, the AS group performed as accurately as the controls, whereas on a verbal labeling task, AS participants made significantly more mistakes in labeling bored postures. Response times of the AS group were significantly slower than controls in their judgments of all three attitudes on both tasks, with the exception only of disagreeing postures on the verbal labeling task. It was hypothesized that these slower response times may reflect a feature-based cognitive processing style by AS participants. Proposed practical recommendations are to train AS individuals in the recognition of boredom, and to improve the speed with which they can recognize different attitudes.     

Workers' postural conditions in the charcoal production proccess based on vertical metallic cylynders

Considering the importance of posture to the workers' health in the production of charcoal, this paper presents an ergonomic research based on a biomechanical focus that aims to evaluate the posture adopted by these workers on the production of charcoal in vertical metallic cylinders. Thus, it was verified the incidence of pain and/or musculoskeletal injuries to these workers. Also, it was evaluated the weight carried by them and the positions taken in their daily tasks. Applying the Ergonomic Analysis of Labor, the data collection was done by directly observing the workers, registering images, by interviews, and posture analysis based on the OWAS method. The main results of the research show that there are postures with risks in the four levels of musculoskeletal injuries classified by OWAS, concluding that the method is imperative for ergonomic recommendations for minimization or eradication of suffering injury and worker's postural constraints.     

Cultural similarities and differences in the semantic dimensions of body postures

We report two studies that examine how differences in social structure between the American and Japanese cultures manifest themselves in differences in the interpretation of body postures. In Study 1, 145 American undergraduates rated 37 posture expressions, using Kudoh and Matsumoto's (1985) semantic differential rating scale. In Study 2, 148 American undergraduates and 150 Japanese undergraduates rated 37 posture expressions, using Mehrabian's (1972) semantic differential rating scale. Factor analysis of the data from both studies indicated a reversal of the primary factors used by the cultures to interpret postures. For the Japanese, judgments were primarily influenced by issues concerning status and power; for the Americans, ratings were primarily influenced by interpersonal responsiveness issues, such as like-dislike judgments. There were also differences in the types of postures indicative of the different factors between the Americans and the Japanese, which were also related to differences in social structure. These differences were discussed in terms of the vertical-horizontal conceptualization of social structure offered by Nakane (1970).David Matsumoto was supported by an American Psychological Association Minority Fellowship under Clinical Training Grant 5 T01 MH13833 from the National Institute of Mental Health, and by a Regents Fellowship and a Chancellor's Patent Fund Award for Research from the University of California at Berkeley.     

Study and analysis of occupational risk factors for ergonomic design of construction worksystems

Manual material handling (MMH) is unavoidable because of the nature of jobs or tasks as and man-machine interfaces in a construction worksystem. Data were collected from six strata of workers viz., masons, mason helpers, carpenters, welders, gas cutters and ground-level helpers (259 out of 700 workers) from a construction site of a steel plant located in India to analyze different types of occupational risk factors, such as awkward posture, repetitive movements and others associated with MMH activities to assess their impact on musculoskeletal disorders (MSDs). It is essential that these risk factors are required to be under control through application of ergonomics-based design approaches for construction worksystem. In this context, multinomial logistic regression analyses were used to identify the significant risk factors among the workers. The results shows that masons, mason helpers, carpenters, welders/gas cutters and ground-level helpers are greatly affected by static body posture, type of tools used, excessive stress due to repetition, awkward postures and extreme climate, respectively. Appropriate preventive and corrective measures are suggested for minimization of risks associated with such jobs/tasks to improve health and performance of the workers.     

Ergonomic evaluation of postural stress in school workshop

The objective of this study is to compare the evaluation of postural analysis between a self-report questionnaire and physical assessments methods for students aged 13 to 15 years old in school workshop. 336 students were volunteered as participants to fill in the questionnaire and being observed in the workshop. Total of 104 positions were selected and analyzed while students performing their tasks. Questionnaire data was examined to specify the prevalence of postural stress symptoms. The relationship of postural stress by physical assessment methods (RULA and REBA methods) was defined to identify the risk level of students' working posture. From the results, comparison of four factors categorized from total of 22 questions among ages, the mean values were lower for 13 years old students meaning that they were faced higher posture problems while using the workstation. The obtained results from both physical assessment methods and questionnaire analysis have identified 13 years old students faced higher risk exposure. Analysis results emphasized the fact that self-reports questionnaire method has almost accurate as postural evaluation methods to identify physical risks in workplace. The result also shows that an intervention is needed to overcome the posture problems.     

Study of postures in sugarcane cutters in the Pontal of Paranapanema-SP, Brazil

The expansion of sugarcane monoculture in Brazil in the last decades has pointed out to the necessity of considering the question of sugarcane cutters occupational health. In this work we present a cross-sectional study aiming to examine the occupational posture of a group of sugarcane cutters, which work in a cane field located in the region of Pontal do Paranapanema- SP, Brazil. The study was made using the Ergonomic Analysis of Work - EAW methodology and the postural analysis method by Win-OWAS. Through the obtained records of postures, it was observed that during a workday the sugarcane cutters remain standing erect on two legs or in one leg 66% of the time and that their trunk remain tilted and in rotation, according to 63% of the positions categorized. It was also observed that the sugarcane cutter trunk performs repetitive and boundless movements during his routine of work, which can expose this individual to additional wear of their musculoskeletal functions. The activities in which the individual engages have favorable or adverse influence on his posture. The repetitive movements involved in specialized occupations are equivalent to repeated exercises, thus may be responsible for the excessive development of certain muscle groups. The study suggests that the postures adopted by sugarcane cutters can overload their musculoskeletal system and predispose the cutters to work-related musculoskeletal diseases.     

Sex Differences in Infants' Mapping of Complex Occlusion Sequences: Further Evidence

Recently, infant researchers have reported sex differences in infants' capacity to map their representation of an occlusion sequence onto a subsequent no‐occlusion display. The research reported here sought to identify the extent to which these sex differences are observed in event‐mapping tasks and to identify the underlying basis for these differences. Two experiments were conducted with 9.5‐, 10.5‐, and 11.5‐month‐olds using the following task. First, infants were shown an occlusion event in which a box and a ball emerged successively to opposite sides of a screen. Then, the screen was lowered and infants saw a single ball on the platform. Boys first showed prolonged looking to the 1‐ball display at 10.5 months, suggesting that at 10.5 months, boys detected the inconsistency between the box‐ball occlusion sequence and the final 1‐ball display. In contrast, girls first showed prolonged looking to the 1‐ball display at 11.5 months. However, girls did show prolonged looking at 10.5 months if they were shown an outline of the box‐ball occlusion sequence prior to the test trials. These results provide converging evidence for the conclusion that boys are more likely than girls to successfully map complex occlusion sequences onto no‐occlusion displays. These results also suggest that boys perform better on event‐mapping tasks because they are more adept at extracting the simple structure of complex occlusion sequences that they can then retrieve and compare to the final display, but that girls can extract the simple structure under more supportive conditions. Possible reasons for these robust, albeit transient, sex differences are suggested.     

The effect of attitudes on emotional reactions to expressive displays of political leaders

One hundred subjects participated in an experiment to assess emotional reactions to the expressive displays of political leaders. Attitudes were assessed through questionnaire items, and facial EMG, heart rate, and skin conductance were recorded while subjects watched silent expressive displays of intense happiness/reassurance, mild happiness/reassurance, and anger/threat by President Reagan and Senator Hart. Half of the subjects reported their global affective reaction during each display, and all subjects reported discrete emotional reactions following each display. For Reagan, main effects were found for display type and for prior attitude in the self-report scales and in facial EMG, although significant Prior Attitude X Display interactions indicated that the intense happiness/reassurance displays most strongly differentiated supporters from opponents. Main effects were found for Hart's displays on the self-report scales and on facial EMG, and post hoc analyses revealed attitude effects. These results support previous research concerning affective reactions to dynamic expressive displays of emotion, but they also show the possible influence of prior attitude toward the expressor on both somatic and subjective measures of emotional response.This research was supported by National Science Foundation Grant SES 83-10176 and the Lincoln Filene Endowment to Dartmouth College and was part of a collaborative project involving Professors Roger D. Masters and Denis G. Sullivan of the Government Department at Dartmouth College. The authors thank Alice Feola for her assistance in preparing the stimulus videotapes. Lauren Bush is now at the Department of Psychology, University of Washington, Seattle, WA. John Lanzetta, our friend and colleague, who contributed so much to this project, died in October 1989 after a year-long illness.     

Evaluation of a personal device in reducing the risk of low back disorders during stooped work

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.     

Effect of low back pain on social and professional life of drivers of Kolkata

Abstract Occupational driving has often been associated with a high prevalence of back pain. Buses constitute the backbone of the local transportation; so many people are engaged in the profession. The present study was to investigate the prevalence of low back pain (LBP) and due to that problem whether their social and professional life hampers or not. The present study was undertaken among 160 government undertaking male bus drivers. Modified Nordic musculoskeletal questionnaire was performed with physical assessment. Then Oswestry Low Back Pain Disability Questionnaire (QLBPDQ) was performed to evaluate the extent to which social and professional life is restricted by back pain. Afterwards, the sit-and-reach test and investigation of sitting postures was done. From the analysis of questionnaire it was revealed that drivers had to spend 8-10 hours daily for 6 days in a shift. It was further observed that all of them mainly suffering from LBP. From the QLBPDQ analysis it was found that LBP restricted their social and professional life. Sit and reach test and posture analysis also support this finding. This result is an absolute reflection of the alarming situations of the Kolkata bus drivers. It can be concluded that the bus drivers are highly stressed due to the hazardous working conditions, which in turn may additionally affects their health and overall work performance in the long run.     

Comparing swimsuits in 3D

In competitive swimming, suits have become more important. These suits influence friction, pressure and wave drag. Friction drag is related to the surface properties whereas both pressure and wave drag are greatly influenced by body shape. To find a relationship between the body shape and the drag, the anthropometry of several world class female swimmers wearing different suits was accurately defined using a 3D scanner and traditional measuring methods. The 3D scans delivered more detailed information about the body shape. On the same day the swimmers did performance tests in the water with the tested suits. Afterwards the result of the performance tests and the differences found in body shape was analyzed to determine the deformation caused by a swimsuit and its effect on the swimming performance. Although the amount of data is limited because of the few test subjects, there is an indication that the deformation of the body influences the swimming performance.     

Assessing manual lifting tasks based on segment angle interpolations

This study investigates the effects of the number of interpolation points on the prediction accuracy of segment angle trajectory during lifting. Ten participants performed various lifting tasks while a motion tracking system recorded their movements. Two-point through ten-point equal time-spaced segment angles extracted from major segment trajectory data captured by the motion tracking system were used to re-generate the whole body lifting motion by using polynomial and cubic spline interpolation methods. The root mean square error (RMSE) between the reference (motion tracking system) and the estimated (interpolation method) segment angle trajectories were calculated to quantify the prediction accuracy. The results showed that the cubic spline interpolation will yield a smaller RMSE value than one based on the polynomial interpolation. While increasing the number of interpolation points can reduce the RMSE of the estimated segment angle trajectories, there was a diminishing advantage in continuing to add interpolation points. A sensitivity analysis suggests that if the estimation of the segment angles at each interpolation point deviates considerably from the real value, and cannot be controlled at a low level (<10 (), the use of higher number of interpolation points will not improve the estimation accuracy.