Zur körperlichen Belastung bei der Arbeit zählen das manuelle Handhaben von Lasten, repetitive manuelle Arbeitsprozesse, das Aufbringen von Ganzkörperkräften, die Körperfortbewegung und die Körperzwangshaltung. Für die Gefährdungsbeurteilung stehen seit Kurzem neue Leitmerkmalmethoden (LMM) zur Verfügung. Sie wurden umfangreich evaluiert und werden als Screening-Verfahren für die praxisnahe Beurteilung zur Anwendung empfohlen.

IntroductionThe assessment of work tasks with physical workloads is crucial to estimate the work-related health risks of employees. Three key indicator methods (KIMs) are available for risk assessment regarding manual lifting, holding and carrying of loads, manual pulling and pushing, and manual handling operations. Three further KIMs regarding whole-body forces, awkward body postures and body movement have been developed de novo. The development of a combined method for mixed exposures is planned. All methods will be validated regarding face validity, reliability, convergent validity, criterion validity.MethodsA mixed-methods study was designed for the validation of KIMs. The following working hypotheses (WH) are tested: WH 1: The KIMs reflect adequately the construct to be measured (face validity). WH 2: No relevant deviations occur between different users using KIMs and assessing the same workplaces (reliability). WH 3: Assessing workplaces using the KIMs and other screening methods will result in no relevant differences (convergent validity). WH 4: It is assumed that employees at workplaces with high KIM risk scores show adverse health related outcomes more frequently than non-exposed workers (criterion validity). With this background a field study was conducted in companies of different sizes and branches in Germany as part of the joint project MEGAPHYS (multilevel risk assessment of physical workloads). Ethics and dissemination: The study was planned and conducted in accordance with the Declaration of Helsinki, the design was approved by ethics committees. We intend to publish validated KIMs in 2018. Acknowledgements/funding: The (further) development and validation of the KIMs is part of project MEGAPHYS funded by BAuA and the German Social Accident Insurance (DGUV). Further MEGAPHYS partners are Institute for Occupational Safety and Health of DGUV (IFA), Institute of Ergonomics at the Darmstadt University of Technology (IAD) and Leibniz Research Centre for Working Environment and Human Factors (IfADo).

IntroductionThe impact of work-related musculoskeletal disorders is considerable. The assessment of work tasks with physical workloads is crucial to estimate the work-related health risks of exposed employees. Three key indicator methods are available for risk assessment regarding manual lifting, holding and carrying of loads; manual pulling and pushing of loads; and manual handling operations. Three further KIMs for risk assessment regarding whole-body forces, awkward body postures and body movement have been developed de novo. In addition, the development of a newly drafted combined method for mixed exposures is planned. All methods will be validated regarding face validity, reliability, convergent validity, criterion validity and further aspects of utility under practical conditions.Methods and analysisAs part of the joint project MEGAPHYS (multilevel risk assessment of physical workloads), a mixed-methods study is being designed for the validation of KIMs and conducted in companies of different sizes and branches in Germany. Workplaces are documented and analysed by observations, applying KIMs, interviews and assessment of environmental conditions. Furthermore, a survey among the employees at the respective workplaces takes place with standardised questionnaires, interviews and physical examinations. It is intended to include 1200 employees at 120 different workplaces. For analysis of the quality criteria, recommendations of the COSMIN checklist (COnsensus-based Standards for the selection of health Measurement INstruments) will be taken into account.Ethics and disseminationThe study was planned and conducted in accordance with the German Medical Professional Code and the Declaration of Helsinki as well as the German Federal Data Protection Act. The design of the study was approved by ethics committees. We intend to publish the validated KIMs in 2018. Results will be published in peer-reviewed journals, presented at international meetings and disseminated to actual users for practical application.

This paper offers an overview of the relation of low back pain (LBP) to occupational exposures to whole-body vibration (WBV) and mechanical shocks. LBP is a condition of multifactorial origin and is a very common health problem in the general population. Among occupational risk factors, epidemiological studies of driving occupations have provided evidence for strong associations between LBP and occupational exposures to WBV and mechanical shocks. Since it is hard to separate the contribution of WBV exposure to disorders in the lower back from that of other individual, ergonomic or psychosocial risk factors, a quantitative exposure-response relationship for WBV cannot be outlined precisely. Experimental research has provided biodynamic support to the findings of epidemiological studies, showing that in controlled laboratory conditions exposure to WBV can cause mechanical overload to the human spine. The EU Directive on mechanical vibration has established daily exposure action and limit values to protect the workers against the risk from WBV. There is some evidence that the EU exposure limit values are excessive, so much so that an elevated risk of LBP has been found for WBV exposures beneath the EU limit values. In the Italian arm of the EU VIBRISKS prospective cohort study of professional drivers, measures of internal lumbar load (compressive and shear peak forces), calculated by means of anatomy-based finite-element models, were found better predictors of the occurrence over time of low back disorders than the metrics of external exposure suggested by the EU Directive on mechanical vibration. Further biodynamic and epidemiological studies are needed to validate the findings of the VIBRISKS study.

At work or in leisure activities, many people are exposed to vibration or mechanical shocks associated with risks of injury or disease. This paper identifies information that can be used to decide whether there may be a risk from exposure to hand-transmitted vibration or whole-body vibration and shock, and suggests actions that can control the risks. The complex and time-varying nature of human exposures to vibration and shock, the complexity of the different disorders and uncertainty as to the mechanisms of injury and the factors influencing injury have prevented the definition of dose–response relationships well proven by scientific study. It is necessary to wave a flag indicating when there is a need to control risks from exposure to vibration and shock while scientific enquiry provides understanding needed to weave a better flag. It is concluded that quantifying exposure severity is often neither necessary nor sufficient to either identify risks or implement measures that control the risks.Practitioner Summary: The identification of risks associated with exposure to vibration and mechanical shock cannot, and need not, rely solely on the quantification of exposure severity. Qualitative methods can provide a sufficient indication of the need for control measures, which should not be restricted to reducing standardised measures of exposure severity.

This experimental study investigated the perception of fore-and-aft whole-body vibration intensity using cross-modality matching (CM) and magnitude estimation (ME) methods. Thirteen subjects were seated on a rigid seat without a backrest and exposed to sinusoidal stimuli from 0.8 to 12.5 Hz and 0.4 to 1.6 ms(-2) r.m.s. The Stevens exponents did not significantly depend on vibration frequency or the measurement method. The ME frequency weightings depended significantly on vibration frequency, but the CM weightings did not. Using the CM and ME weightings would result in higher weighted exposures than those calculated using the ISO (2631-1, 1997) Wd. Compared with ISO Wk, the CM and ME-weighted exposures would be greater at 1.6 Hz and lesser above that frequency. The CM and ME frequency weightings based on the median ratings for the reference vibration condition did not differ significantly. The lack of a method effect for weightings and for Stevens exponents suggests that the findings from the two methods are comparable.PRACTITIONER SUMMARY:Frequency weighting curves for seated subjects for x-axis whole-body vibration were derived from an experiment using two different measurement methods and were compared with the Wd and Wk weighting curves in ISO 2631-1 (1997).

In a prospective cohort study of 537 male professional drivers, the occurrence of sciatic pain showed stronger associations with measures of internal lumbar load expressed in terms of daily compressive dose, S(ed) (MPa), and risk factor, R (non-dimensional), according to ISO/WD 2631-5 (2013), than with measures of daily vibration exposure calculated as either 8-h energy-equivalent frequency-weighted acceleration (ms(-2) r.m.s.) or vibration dose value (ms(-1.75)) according to the EU Directive on mechanical vibration (2002). Herniated lumbar disc, previous lumbar trauma and physical work load were also powerful predictors of the occurrence of sciatic pain over time. Psychosocial work environment was poorly associated with sciatic pain. The boundary values of risk factor (R) for low and high probabilities of adverse health effects on the lumbar spine, as proposed by international standard ISO/WD 2631-5 (2013), tend to underestimate the health risk in professional drivers.PRACTITIONER SUMMARY:In a prospective cohort study of professional drivers, measures of internal spinal load were better predictors of the occurrence of sciatic pain than the measures of daily vibration exposure established by the EU Directive (2002). Herniated lumbar disc, lumbar trauma and physical work load were also associated with sciatic pain.

The present study aimed to (1) employ the method for evaluation of vibration containing multiple shocks according to ISO/CD 2631-5:2014 (Model 1) and DIN SPEC 45697:2012 in a cohort of 537 professional drivers, (2) deliver the results for a re-analysis of epidemiological data obtained in the VIBRISKS study, (3) clarify the extent to which vibration acceleration and individual variables influence risk values, such as the daily compressive dose S-ed and the risk factor R, and (4) compare the results with in vivo measurements and those obtained in previous studies with similar models. The risk factor R was influenced by the acceleration, lifetime exposure duration, sitting posture, age at the start of exposure and body mass/body mass index in order of decreasing effect. Age and annual and daily exposure duration had only a marginal effect. The daily compressive dose S-ed and the risk factor R showed weak linear association with the daily vibration exposure A(8) and the vibration dose value VDV. The study revealed high shear forces in the lumbar spine. Practitioner Summary: In a re-analysis of an epidemiological study of professional drivers, a software tool available with standards DIN SPEC 45697:2012 and ISO/CD 2631-5:2014 Model 1 was used to calculate the risk to the lumbar spine in terms of daily compressive dose S-ed and risk factor R. The tool was found to be suitable for risk assessment in a large cohort.

Objective: The aim of this study was to compare the performance of alternative measures of cumulative lifetime vibration dose to predict the occurrence of low-back pain (LBP) outcomes in a cohort of 537 professional drivers investigated at baseline and over a two-year follow up period. Methods: The exposure data obtained in the EU VIBRISKS project were used to calculate alternative measures of either acceleration- (external) or force- (internal) based lifetime vibration doses. Vibration was measured in representative samples of machines and vehicles used by the drivers. Internal lumbar forces were calculated by means of anatomy-, posture-, and anthropometry-based finite element models. The relations of LBP outcomes to alternative measures of lifetime vibration doses were assessed by the generalized estimating equations method. Results: Metrics of cumulative vibration exposure constructed with either acceleration- or force-based methods were significantly associated with the occurrence of LBP outcomes. A measure of model fitting suggested that force-based doses were better predictors of LBP outcomes than acceleration-based doses. Models with force root-mean-square doses provided a better fit to LBP outcomes than those with force-peak doses. Conclusions: Measures of internal lumbar forces were better predictors of LBP outcomes than measures of external vibration acceleration although the exposure metrics constructed with the acceleration-based method have the advantage of greater simplicity compared to the force-based method. The differences between the models with force-based doses suggest that the cumulative health effects on the lumbar spine might depend on the integrated resulting total force over the entire exposure time rather than primarily on the force peaks.

Gefahrdungsbeurteilungen bei physischen Belastungen stellen aufgrund der Vielseitigkeit der Belastungen eine komplexe Aufgabe dar. Die Bundesanstalt fur Arbeitsschutz und Arbeitsmedizin (BAuA) und die Deutsche Gesetzliche Unfallversicherung (DGUV) haben gemeinsam mit Kooperationspartnern das Forschungsprojekt MEGAPHYS (Mehrstufige Gefahrdungsanalyse physischer Belastungen am Arbeitsplatz) zur Vervollstandigung und Validierung geeigneter Beurteilungsverfahren fur die Praxis gestartet.

In a laboratory experiment, six male subjects were exposed to sinusoidal (0.8, 1.6, 3.15, 6.3 and 12.5 Hz) or random octave band-width white noise (mid-frequencies identical to those of the sinusoidal vibrations) whole-body vibration in x- or y-directions, at six levels of magnitude (0.4, 0.8 and 1.6 m/s2 r.m.s. non- and frequency-weighted) with two repetitions. In order to examine time effects, additional reference stimuli were used. Each subject was exposed to these 304 exposure conditions with a duration of about one minute on four different days (76 exposures per day). The subject's sensations of vibration intensity and vibration comfort were obtained by cross modality matching (length of a line). The subjects sat with an upright posture on a hard seat without backrest, hands on the thighs. The derived equivalent sensation contours suggest an underestimation of the sensation varying in extent from 2 dB to 8 dB at 1.6, 3.15, 6.3 and 12.5 Hz in comparison with the reference frequency 0.8 Hz for both types and directions of signals by the current evaluation methods according to ISO 2631-1 with the most pronounced effects revealed at the frequencies 3.15 and 6.3 Hz and at lower intensities (overall vibration total value aov around 0.48 m/s2 to 0.8 m/s2 at the reference frequency 0.8 Hz).

The development of suspension systems for vehicles requires knowledge of the association between objective and subjective data. One question to be answered by this experimental study was if the driver's body movements had similar effects as the magnitudes of the vibration exposure on the judgements of the vibration intensity, the seat comfort and the effort to carry out a foot pedal pressing task. Moreover, it was of interest, if the vibration measuring points (seat surface, feet, seat backrest) played an important role. Additionally, the adequacy of the frequency weightings according to ISI 2631-1 concerning subjective judgements should be verified.Twelve male subjects took part in the experiment. They sat on two different driver seats in relaxed posture using a hand support. Seat 1 was excited in x-direction, Seat 2 either in x- or in y-direction, on three levels of vibration magnitude with exposure duration of 166 seconds for each condition. There was a different frequency content of vibration signals of the two seats and in the x- and y-directions. The following values were measured: (i) accelerations in three directions at the feet (platform), at the seat frame under the seat cushion but above the suspension, at the seat cushion, at the seat backrest, (ii) body movements: head, hand, foot, knee and hip with a three-dimensional motion-analysis-system (infrared cameras), (iii) subjective judgements of the vibration intensity, of the seat comfort and the effort to carry out a reaction task with cross modality matching (length of a line), (iv) reaction times for pressing the foot pedals,,accelerator" and,,break".The subjective judgement of intensity seems to depend rather on the vibration magnitude at the buttocks, the back and the feet than on the movements of the body parts in relation to the spatial coordinates or the relative movements between the body parts. Probably, the vibration measuring point is of minor importance for the association between acceleration and judgement of intensity. It is possible that the influence of the body movements on the judgements will increase when they exceed the level observed in the current study. Perhaps, the frequency weightings according to ISO 2631-1 do not adequately reflect the subjective judgement, at least with respect to the assessment of the intensity.The results did not permit reliable estimates of the subjective judgements of the seat comfort and the effort to carry out the reaction task based on objective values. Nevertheless, there was a week linear association between the relative head movements within the spatial coordinates and the judgements of the effort. This effect was only observed during excitation in x-direction (fore-aft), not during exposure in y-direction. The results could indicate an increasing annoyance by a continually altering distance between the eyes and the screen of projection. The disturbance of the visual system may have played an important role during the reaction task.

The optimal design of driver seats with horizontal suspension requires knowledge of human response with respect to the perception of the vibration intensity and seat comfort or of the performance in motor tasks. In an experimental study, 12 male volunteers (body mass 59–97.3kg) were exposed to whole body vibrations in isolated x- or y-direction (three levels of magnitude) and biaxial xy-direction (combination of the x- and y-exposures on level two) sitting on a driver seat. The suspensions in x- and y-directions were randomly locked or unlocked. A brake and an accelerator foot pedal had to be pressed on demand as fast as possible. The perceptions of the vibration intensity, the seat comfort and the effort to carry out the motor task were judged by cross modality matching (modality: length of a line). The intensity judgements significantly increased with raising vibration magnitude. They were significantly higher for locked suspension. With only some exceptions, the judgements of the seat comfort decreased significantly with increasing magnitude, locked suspension and time. The effort judgements significantly increased with raising magnitude and time and revealed a tendency towards a lower effort with activated suspension. The reaction times showed no significant influences of vibration magnitude, suspension or time, but higher demands seemed to be compensated by enhanced effort. The wd-weighting did not adequately reflect the perceptions for the frequency spectra applied in this study in the x-axis. A modified ‘overall vibration total value’ determined from the non-weighted accelerations instead of the weighted ones (ISO 2631-1, Article 8.2.3) corresponded with the subjective judgements in case of exposure in x- and xy-directions. A clear definition of ‘comfort’ or ‘discomfort’ or the use of ‘intensity’ instead of these terms is recommendable.

Seats with horizontal suspensions can help to reduce detrimental effects of whole-body vibration (WBV) on health, comfort and performance. Two seats were used to examine the effect of body mass and WBV-magnitude on the transmission of WBV from the seat base to the cushion. Both seats have suspension in the x-direction while Seat 2 has suspension also in the y-direction. Twelve subjects with a body mass ranging from 59.0 to 97.3kg volunteered for the study. A set of anthropometric characteristics was acquired. Three magnitudes of WBV were used with a truck-like signal (Seat 1, 0.3–0.59ms−2 wd-weighted rms values at the seat base, x-direction) and a tractor-like signal (Seat 2, 0.55–1.09ms−2 wd-weighted rms values at the seat base, x-direction, 0.52–1.07ms−2 wd-weighted rms values, y-direction). The magnitude of WBV had a significant effect on the transmissibility characterized by SEAT-values. A significant influence of the body mass on SEAT-values was found for the y-direction only. Other anthropometric characteristics proved to be more important for the prediction of SEAT values by multiple regressions. There was no significant correlation of SEAT-values, x-direction, with the body mass. Other anthropometric characteristics enabled a satisfactory prediction of SEAT values also for x-direction in several cases. Tests with only two subjects of extreme body mass are not suited to obtain comparable and representative results required for a comparison of different seats with a suspension in the x-direction. The effect of the WBV-magnitude on the WBV-transmissibility should be considered with the design, testing and application of suspended seats.

BACKGROUND:The biologic plausibility for noise stress-related cardiovascular responses is well established. Epidemiologic studies on the relationship between transportation noise and ischemic heart disease suggest a higher risk of myocardial infarction in subjects exposed to high levels of traffic noise. METHODS:To determine the risk of road traffic noise for the incidence of myocardial infarction (MI), we carried out a hospital-based case-control study in the city of Berlin. We enrolled consecutive patients (n=1881), age 20-69 years, with confirmed diagnosis of MI from 1998 through 2001. Controls (n=2234) were matched according to sex, age, and hospital. Outdoor traffic noise level was determined for each study subject based on noise maps of the city. Standardized interviews were conducted to assess possible confounding factors and the annoyance from various noise sources. RESULTS:The adjusted odds ratio for men exposed to sound levels of more than 70 dB(A) during the day was 1.3 (95% confidence interval=0.88-1.8) compared with those where the sound level did not exceed 60 dBA. In the subsample of men who lived for at least 10 years at their present address, the odds ratio was 1.8 (1.0-3.2). Noise-exposed women were not at higher risk. CONCLUSIONS:The results support the hypothesis that chronic exposure to high levels of traffic noise increases the risk for cardiovascular diseases.

This review concentrates on the effects of low frequency noise (LFN) up to 100 Hz on selected physiological parameters, subjective complaints and performance. The results of laboratory experiments and field studies are discussed in relation to the thresholds of hearing, of vibrotactile sensation and of aural pain. The effects of LFN may be mediated trough different ways. Temporary or permanent hearing threshold shifts seem to be due to acoustic stimuli above the individual hearing threshold. However, non-aural physiological and psychological effects may be caused by levels of low frequency noise below the individual hearing threshold. The dynamic range between the thresholds of hearing and of aural pain diminishes with decreasing frequency. This should be taken into account by the setting of limits concerning the health risks. Sufficient safety margins are recommended. The use of a frequency weighting with an attenuation of the low frequencies (e.g. G-weighting) does not seem to be appropriate for the evaluation of the health risks caused by LFN up to 100 Hz. It may be proposed to measure third octave band spectra or narrow band spectra. A comparison with the known human responses caused by the measured levels and frequencies could help to evaluate the health risks. Some proposals for further investigations were given: (1) experimental methods to discover the ways mediating the effects of low frequency noise, (2) consideration of the individual hearing threshold or hearing threshold shift and of the vibrotactile threshold in the low frequency range to be able to judge the effects, (3) consideration of combined body vibration caused by airborne low frequency noise or by other sources, (4) modelling to analyse the transmission of the acoustic energy from the input into the body to the structures containing sensors, (5) consideration of probable risk groups like children or pregnant women.