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Whole-shift field studies of the load
on the lumbar spine during occupational manual materials handling (Vol. 2/99) Authors: Matthias Jäger, Alwin Luttmann, Claus Jordan and Wolfgang Laurig Keywords: Lumbar load; manual materials; handling; biomechanics; shift dose; overexertion risk; field studies Summary:Investigations
into the load on the lumbar spine during manual materials handling are mainly available
with respect to short activity sections or to selected types of manipulation. Concerning the term physical
performance capacity and its relevance for Author: Hans-Volkhart Ulmer Keywords: Complexity of performance capacity; physical performance capacity; ergometric performance capacity; ergometry; preventive disability screening; simulators for test and training Summary: Physical
performance capacity is a frequently used term in industrial and sports medicine as well
as in ergonomics. Like the five motor forms of strain: coordination, force, endurance,
speed capacity, and flexibility, physical performance capacity is well suited to classify
the manifestations of human performance capacity in itself. Due to the complexity of human
performance and the specifity of adaptive processes, ergometric performance capacity is
unable to represent the professional performance capacity. Particularly, if one considers
that
solutions of professional tasks require not only coordination but also experience. Hearing Threshold Shifts
Associated with Impulse Noise - Influence of the Authors: Hartmut Irle, Günther Hinzmann and Helmut Strasser Keywords: Impuls Noise Exposure; Impulse Number; Impulse Duration; Temporary Threshold Shift; TTS2; Restitution Time Summary: An increase in the number of impulses and a corresponding shortening of the impulse duration during energy-equivalent impulse noise exposures leads to a significant increase in the temporary threshold shift TTS2, the restitution time, and the integral of the hearing threshold shifts, the IRTTS-value. However, it has been unclear so far whether this increase in physiological cost is due to the duration or the number of impulses. Therefore, test series were carried out in order to analyze the effect of variations in the number of impulses with constant impulse duration and vice versa. Doubling or halving the number of impulses according to a variation of the exposure by ±3 dB was associated with clear increases and decreases in all 3 audiometric variables. Variations of the impulse duration by the factor 2 led to generally smaller changes of the dependent parameters. When adjusting the results which are determined by changes in the rating level by ±3 dB, too, an increase of the number of impulses is still associated with an essential increase of the IRTTS-values, though energy-equivalent conditions now can be assumed. However, the increase of the impulse duration did not result in an increase but even in a decrease. Upon the Efficiency of
Personal Hearing Protectors Resulting from Authors: Helmut Strasser, Hartmut Irle and Thorsten Siebel Keywords: Attenuation of hearing protectors; Reduced wearing time; Predicted versus actual protection loss; Temporary threshold shifts Summary: If hearing protectors are
unused for only a short time, their attenuation according to
international standards is reduced drastically. Whether this actually occurs was to be
investigated in studies during which 10 test subjects (Ss) were exposed to noise at a
level of 94
dB(A), continuously, for 1h. In a further test series (TS), during which earplugs with an
attenuation of 30 dB were provided, the Ss were exposed to noise at a level of 106 dB(A)
for
1 h. The protectors were inserted just 3¾ min after the noise exposure began. According
to
the energy equivalence principle, this constellation leads to an equivalent noise exposure
of 94
dB(A) / 1 h. Therefore, the attenuation of the earplugs which went unused for 3¾ min
during
1h seems to deteriorate by 18 dB to only 12 dB. Furthermore, the influence of several
short-time removals of the earplugs on the attenuation was simulated. Calculation models for a
computer supported determination of actual Authors: Bernd Hans Müller and Hansjürgen Gebhardt Keywords: Climate assessment; calculation models; heat stress; climate indices Summary: The normal effective
temperature, the basis effective temperature as well as the WBGT index are climate indices
which are applied for the assessment of the climatic conditions at warm and hot
workplaces. Thus, the reference values, as of which occupational medical preventive
checkups have to be carried out, are based on the normal effective temperature, the basis
effective temperature is e.g. applied in coal-mining, the WBGT index is recommended within
the ZH1/174 for those workplaces at which work has to be carried out under hot conditions
with high air temperature, humidity and radiation. For the determination of the effective
temperatures usually nomograms are being used, the determination of the WBGT index
requires the knowledge of the globe temperature and the naturally ventilated wet-bulb
temperature, which aggravates the application for prognoses of changed conditions. Cardiovascular parameters
under repeated mental and static demands with Authors: Klaus Scheuch, Reingard Seibt and Dorit Nöthel Keywords: Peripheral blood pressure; brachial blood pressure; reproducibility; mental; static Summary: The stability of cardiovascular parameters was investigated in repeated measurements after one day, one week and one months. The peripheral blood pressure (BP), assessed with finapres, the brachial BP and heart rate were measured under mental (arithmetic tasks and a modified Stroop-test) and static (fingergrip with 30% of maximal strength) demands in 20 normotensive men in laboratory. All of the physiological and performance (right solved tasks) data differed significantly between the first and second investigation. Only the peripheral BP showed a continuous decrease in the further tests, similar as the performance data. In the subjective feeling we did not find any significant changes in this four investigations. These physiological changes reflecting adaptation were depending on the kind of demand. The adaptation effects were more pronounced in mental (especially in systolic BP) than in static (especially in diastolic BP) tasks. Product-Ergonomic Evaluation
of Diagonal Cutting Nipper Handles by Authors: Karsten Kluth, Dirk Zühlke and Helmut Strasser Keywords: Diagonal Cutting Nippers; Two-legged Working Tools; Product-ergonomic Evaluation; Electromyography; Subjective Assessment Summary: For the development of ergonomically optimized types of pliers' handles, 8 typical diagonal cutting nippers were compared and evaluated with respect to the handle design. 11 male, right-handed test subjects (Ss)repetitively had to cut medium-hard and soft wires (according to DIN ISO 5744) at a special device and in a standardized execution. By means of the surface electromyography the muscle strain (mean values from 20 cuts) of the m. flexor digitorum, m. extensor digitorum, m. flexor carpi ulnaris and m. biceps in the right hand-arm system were continuously registered. Furthermore, specific questionnaires with 35 items were developed with which the Ss subjectively evaluated pliers and handles criteria such as design, material, dimensions, weight and handling as well as work effects on the human body. The determined objective measured data in combination with the obtained subjective assessments allowed conclusions about design criteria and design approaches for the optimization of pliers handles. Activation of the Finger and
Trapeze Muscles in Repetitive Short and Long Authors: Michael Schnoz, Thomas Läubli, Joseph A.Weiss und Helmut Krueger Keywords: work-related musculoskeletal disorders; repetitive work; low-intensity work; computer work; EMG Summary: The modelling of the
development of neck pain, which is highly prevalent in computer workplaces, implies the
knowledge of the activity patterns of the involved muscles of fingers, upper arms and neck
during repetitive tasks at low intensity. For this experiment, nine subjects tapped with
the index finger, at different given frequencies, during eight seconds and then for the
longest possible duration, on a rigid key. The analysis of the surface EMG signals of six
muscles and of the force on the key found, with fast and slow tapping and during
relaxation, that static contraction was present in the finger and trapeze muscles, but not
in the upper arm muscles. The static contraction of the trapeze muscle did not alter
significantly during the long-term experiments. Significant phasic co-activity was found
only rarely in the upper arms, but significantly, and increasing with time - however not
synchronous with the finger movement -, in the trapeze muscle. The observed incomplete
relaxation of the trapeze muscle during tapping and even during conscious relaxation could
possibly constitute a reason for the Impact of visual performance
on detection of impestation of vine leaves by Authors: Reinhard Dietrich, Marino Menozzi, Mauro Jermini, Cesare Gessler and Phillipe Blaise Leywprds_ Detection; visual power; plasmopara viticola (downy mildew) Summary: In modern plant protection a plant disease should be controlled only after its intensity has reached the damage threshold. In the case of downy mildew, caused by Plasmopara viticola and one of the most feared grapevine diseases, the detection rate of the disease symptoms is smaller than one and there is a large variability in the probability of discovery of these symptoms between the individual scorers. In this work possible causes of this variability are examined, such as a different visual power between the scorers (visual acuity, color vision, asthenopic complaints, stereopsis, near and far point, amplitude of accommodation) or their sampling methods. The experiments conducted in this work can be divided into two types. First, the influence of the counting unit on accuracy and precision was examined; two counting units were used: number of lesions per shoot and numbers of infected leaves per shoot. Second, the influence of the searching method "intensive sampling" versus "superficial sampling" on accuracy and precision was examined. The choice of the search procedure influenced significantly the detection performance, this in contrast to the counting method. The visual power can explain 20% of the variability. In the statistical analysis regularities were found, which allowed to classify the scorers according to their detection rate and revealed that the scorers rank the samples into a congruent order, which is not identical with the "true" one. From this it can be concluded that the higher cognitive processes play an important role in the detection of P. viticola symptoms. Interaction work. Concept and method in hospitals (Vol. 3/99) Authors: André Büssing and Jürgen Glaser Keywords: Interaction work; emotion work; sentimental work; burnout; job satisfaction; nursing Summary: A concept of interaction work is introduced referring to the research on emotion work and sentimental work and combining a person with a condition-related approach. In the centre of the concept are main characteristics of interaction with clients like frequency, duration and intensity and characteristics of emotion work like emotional harmony, emotional deviance and emotional dissonance. For purposes of measurement two instruments are introduced: the Interaction Characteristics Questionnaire and the Emotion Work Questionnaire. Both show good reliability and validity. Furthermore potential outcomes of interaction work on emotional exhaustion and job satisfaction with 298 nurses are investigated. According to the results of stepwise regression analyses frequency of interactions with person-alities and emotional deviance proof to be important predictors of emotional exhaustion and job satisfaction. Finally, benefits and boundaries of the two instruments of interaction work in nursing and implications for future research questions as well as for education and training in person- elated services are discussed. Not only more quality but
also higher efficiency - subjectifying work action Author: Fritz Böhle Keywords: Subjectifying work action; limits to planning and standardization; sensory perception; tacit knowledge Summary: A fundamental characteristic of working with the elderly is the limit to calculating or planning everything in advance. For this reason, in both scientific analyses and practice, a concept of work is necessary that is not oriented by the usual model of calculated, rational action. Such a concept is subjectifying work action. This concept is directed toward a form of work which deviates from typical rationalistic forms of planning, but nevertheless contains its own systematic structure. The bases for this structure are interaction and dialogue, a complex use of sensory perception, subjective feelings and empathy as well as mental processes that are linked to actions and behaviours. In this paper, concrete manifestations of subjectifying work practices in care of the elderly, which derived from empirical research based on qualitative case studies, are presented. Also, consequences for a quality-oriented as well as efficient organization of care of the elderly are discussed. Sentimental work - an attempt to definition (Vol. 3/99) Author: Ursula Brucks Keywords: Sentimental work; Lazarus' concept of emotions; person-related services Summary: Sentimental work is likely
to become a term of some importance in the field of work Emotional dissonance and
burnout. An examination in the nursing sector Authors: Friedemann W. Nerdinger and Matthias Röper Keywords: Emotional dissonance; burnout; Workload; resources; interaction work Summary: The interrelations between work load, resources, emotional dissonance and burnout were studied with nurses of an university hospital. Leiter (1993) has proposed a model in which work load and resources are posited to be differentially associated with the three dimensions of burnout. The propositions of his model could be confirmed. Faking in good faith as one form of emotional dissonance was strongly positively related to personal accomplishment and had negative correlations with emotional exhaustion and depersonalization. The expected relations with faking in bad faith could not be confirmed. The long-term care insurance
and occupational stress among caregivers in Authors: Andreas Zimber, Anja Albrecht and Siegfried Weyerer Keywords: Occupational stress; homes for the elderly; long-term care insurance; follow-up study Summary: Due to the changes following the establishment of the long-term care insurance in Germany, occupational stress among caregivers in long-term care institutions is assumed to increase. We aimed to test temporal changes in the job conditions and in job strain by a representative follow-up study in 15 homes in the city of Mannheim between 1996 and 1998. 304 geriatric caregivers were surveyed before, 243 caregivers one year and 213 two years after the long-term care insurance had been established. 80 persons participated in all three waves. The results confirmed marked changes in the job conditions of the caregivers in the institutions observed: Within two years, the home personnel was reduced significantly; discrepancies between the job expectancies and perceived job conditions increased significantly, whereas organizational resources diminished. There also was evidence for an increasing prevalence of physical and mental health problems. Regression analyses revealed, that the health problems were best predicted by the increasing discrepancies. To prevent existing health problems from deteriorating, intervention strategies must be implemented. Stressors and resources of call center jobs (Vol. 3/99) Authors: Amela Isic, Christian Dormann and Dieter Zapf Keyword: Call Center; service; stress; resources Summary: Call centers are one of the booming branches in the service sector. In the present study, the working conditions of 250 call center employees were analyzed whose jobs mainly consisted of calling or being called by customers. In comparison with two samples of administrative office workers and bank employees, call center employees turned out to have very low task-related and time-related job control. In particular, this was the case for inbound jobs (customers were calling only) in comparison to jobs with in- and outbound (employees being called and actively calling customers). Moreover, task- and time-related control were particularly low when the average call time was low. Compared with the other samples, psychosomatic complaints were significantly higher among call center employees. Holistic task design in
nursing. A contribution to improve person-related Authors: Jürgen Glaser and André Büssing Keywords: Task design; complete activity; holistic nursing; patient-orientation; person-related services Summary: At the centre of the article is the question how far complete, patient-oriented task design in nursing is or can be realised and how it can contribute to improve the quality of person-related service work. Starting from different ways of work design structures and processes that characterise nursing in hospitals are illustrated. Moreover, empirical results for the negative influence of partialised nursing tasks are presented. Against the background of a model project dealing with the implementation of a so-called patient-oriented domain nursing possibilities for holistic task design in nursing are illustrated and perspectives of improving person-related services in hospitals are discussed. Functions of Prototyping in the Design Process (Vol. 4/99) Authors: Pierre Sachse, Sven Leinert, Martin Sundin and Winfried Hacker Keywords: Prototyping; Engineering design; Design problem solving Summary: A series of questionaire studies analyses and evaluates the possibilities of external assistance of the demanding cognitive activities in engineering design. Special emphasis is put on the early phases of the design process. The support of the designer -especialy in the early phases- is a key issue for improvements of efficiency. The functions especialy of rough sketches and simple models applying materials-at-hand are identified. The consequences for the possibilities and requirements of assistance in the design process are discussed. Fitts' law in mouse and
trackball: an experimental test for the ergonomic Authors: Henrik Zöller and Sigrid Konheisner Keywords: Fitts' law; mouse; trackball; computer input devices; ergonomics; design Summary: Two commercial computer
input devices (Microsoft Serial Mouse & LogiTech Trackman) were compared in an
experimental long-range study with respect to their efficiency in a representative task.
The experiment consisted of simple, aimed movements of a Cursor
towards a resting object presented on a CRT, ending with a manipulation of the
click-button
(move-and-click-task). In this representative task movement times with trackball are 129
ms
longer than movement time with mouse (within-subjects-design). All subjects perform faster
with mouse in comparison to trackball, even after a long lasting training period of 19
sessions. European and international
standardization activities in the area of Author: Karlheinz Schaub Keywords: Manual Materials Handling; Standardization; CEN; ISO; EU - Directives Summary: During the recent 10 years ISO and CEN draft standards have been developed in the field of the manual lifting and carrying of loads. Despite of controversy discussions, partly politically motivated, two draft standards on that topic are available now. Wheras the CEN draft standard, mandated by the EU GD III within the machinery directive addresses to the designer of machinery, offering guidelines for the design of machinery concerning a manual lifting and carrying of loads, the ISO approach focuses onto employers and employees that are responsible for the workplace design during the use of machinery. The following paper presents standardization guidelines at CEN and ISO and offers essential details of both draft standards, demonstrates the relationship between ISO and CEN in that work area and positions both drafts within the field of the dual concept of safety at work in Europe. Sensation and evaluation of drafts (Vol. 4/99) Author: Barbara Griefahn, Ulrike Gehring and Christa Künemund Keywords: Drafts; annoyance; air velocity; turbulence intensity; air temperature; physical activity; draft-rating model (ISO 7730) Summary: Annoyance due to drafts was recorded in 6 experimental series where altogether 107 participants (33 women, 74 men, 18 - 51 years of age) were exposed to defined drafts during a total of 826 one-hour sessions. Air velocity turbulence intensity, direction of drafts (horizontal, vertical, diagonal), air temperature, and metabolic rate were systematically varied, but kept constant during the single sessions. Annoyance due to drafts increased with mean air velocity and/or with turbulence intensity as well as with the decrease of air temperature and of metabolic rate, whereas the direction of drafts had no influence. These responses were neither sufficiently predicted by the Draft-Rating model proposed in ISO 7730 (1994), nor by its extension, developed by Toftum (1994a). After the modification of the latter the percentage of persons annoyed by drafts was predicted with sufficient accuracy. The correlation coefficient between predicted and observed percentages was r = 0.726 (p < 0.001). As the resulting model covers larger ranges of air temperature and metabolic rate it is suggested to substitute the model in ISO 7730 (1994). Use of communication media
under telework. A report from the field. Authors: André Büssing, Patrick Broome and Sandra Aumann Keywords: Telework; communication media; media choice; qualification Summary: We have asked experts of eight leading enterprises of industry, of financial and insurance services as well as from information and communication technology with tasks in research, consulting, service and production about their experiences regarding the use of different communication media and qualification under telework. We pass the empirical report on here as it were from first hand. Beside considerations for the technical realization of telecooperative work organization the data confirm the considerable impact of teleworking on organizational change especially because of the changes in the use of communication media; this should be taken into account by involving the employees in the process of implementation and by integrating training and qualification of superiors and coworkers. Finally costs and benefits will be discussed against the background of the experiences of the enterprises under study. Living- and working
situation of female nightshift workers: an empirical Authors: Karen Spannhake and Gine Elsner Keywords: Female nightshift workers; car industries; old and new states of the federal republic of germany; influence on health and life quality Summary: In the middle of 1994 a new law with regard to the working hours was passed where it was possible to employ female nightshift workers in production plants all over the country. In spring 1998 altogether six companies were involved in a written and oral questioning of female nightshift workers. The formulation of the questions was to find out how women in car production assessed the situation of their working life and their situation of health. 405 questionnaires could be used for the statistic evaluation. Three of the companies chosen for the study are based in the new, three more are based in the former states of the federal republic of germany. Parallel to the written questioning personal interviews were held in three companies. Another company in Hessen were additional involved. 57% of the women are satisfied with the nightschift. The most are living in the western states of the federal republic. But 31% noticed that their health was getting worser in the time of nightshift. More women from the east remarked that. An ambivalent attitude to nightshift and its consequences was visible. Organizational democracy -
stimuli for innovative forms of work beyond Author: Wolfgang G. Weber Keywords: Organizational democracy; co-determination; self-management; participation; organizational design; factors of succes Summary: Several principles and current connections of organizational democracy to research topics of industrial engineering and management will be considered. Criteria for the differentiation of democratic and undemocratic participation levels are proposed. Diffusion, forms, contents, prerequisites, and problems of organizational democracy are described in the context of reform enterprises, collectivist enterprises, and communitarian organizations, which all have a democratic constitution. Results are summerized that refer to connections of democratic organization structures to criteria, which are of relevance for work and organizational psychology, as well as for industrial sociology, for example work motivation, job satisfaction, readiness for cooperation, prosocial work orientations, political involvement, and economic viability. With reference to some desiderata relating to contents and methodology, stimuli for future research as well as for a transfer of several results to innovative small and medium-sized firms are given. |