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Biomedical subjects

W Rohmert

Publications and source records attributed to W Rohmert.

At least 19 recordsLinked to original sources

Ergonomic research study on aircraft luggage handling.

In this study, the lifting and carrying of freight and luggage at a large German airport is classified by typical conditions of performance. These manual load handling tasks take place in height-restricted workplaces. Different methods for an ergonomic evaluation of these tasks are used. The results of the epidemiological, physiological, and biomechanical studies indicated a strain bottleneck during loading tasks in aircraft holds. Therefore, an additional laboratory study was done, in order to analyse the influence of work weight and weight of work object on heart rate, subjective RPE, and number of work objects handled. As a result of the study, the airport has developed a special lifting and carrying training for the aircraft handlers which aims to reduce strain on the postural and locomotor apparatus by an appropriate technique of work. The training programme consists of theoretical instruction by a company doctor and practical exercises under the supervision of a specially-trained sports teacher.

Accidents, Occupational

Ergonomic evaluation of a wheelchair for transfer of disabled passengers at a large airport.

Transferring disabled passengers to the aircraft, both arriving and departing, is one passenger service at a big airport. We use different ergonomic research methods (registration of heart rate, AET job analysis as well as a standardized questionnaire) to evaluate the present wheelchair design. Due to e.g. the high wheelchair backrest, the forces needed to handle the chair and other facts, the current wheelchair causes a strain bottleneck. The results of the AET analysis and the rating of the perceived exertion confirm this finding. A redesigned wheelchair based on ergonomic principles, which reduces stress on the employees and offers more comfort to disabled passengers, is presented.

Aviation

Effects of vibration on arm and shoulder muscles in three body postures.

The electromyographic responses of arm and shoulder muscles to vibrations were studied in three postures similar to the postures of drilling in a ceiling, drilling in a wall and drilling in a floor. This experiment was performed within the defined parameters of: vibrational frequency at 30 Hz, acceleration level 40 m.s-2 (rms), pushing force expressed as percentage maximal voluntary contraction, and gripping force which was set at 100 N. The exposure time for each test was 5 min. The general findings from these three body postures show that all the examined muscles were affected by exposure to vibration. The EMG index increased as follows: trapezius muscle 39% (p less than 0.05), lower-arm flexor muscles 23% (p less than 0.05), infraspinatus muscle 14% (p less than 0.05), lower-arm extensor muscles 14% (p less than 0.1) and biceps muscle 6% (p less than 0.1). The muscle most affected by vibration was found to be the trapezius muscle. It should be taken into consideration that vibration can be a contributing factor in neck/shoulder disorders among power handtool operators. The general conclusion from this study is that changes in working posture give different transmissions of vibration in the upper extremities. It seems as if the prime movers and muscles with an increased muscle length or increased degree of contraction are most affected by vibration.

Adult

[Tremor reaction to mental and emotional stress].

Reactions of tremor before and after stress were registered with a new method. Reactions with informatory-mental stress (adding tests with increasing time pressure) can only be interpreted by considering performance. Reactions with informatory-emotional stress (University examination; tasks in a central TV control room) are task specific when tremor is inter-individually normalized.

Fingers

[Evaluation of human strain during interrupted exposure to vibration (author's transl)].

The psychophysical reactions to stochastic vibrations transmitted in vertical direction to sitting man are investigated in simulated experiments under laboratory conditions. In the framework of an appropriate concept of assessment, indicators related to bottleneck situations in functional systems of the organism for activity and strain measurements allow the evaluation of the recreation efficiency of interruptions in exposure time. The special meaning of the distribution and thus the frequency rate of the interruptions can be illustrated particularly by the variance in time of the strain processes of selected muscles. Between the degree of muscle fatigue and the period of uninterrupted exposure time (expressed in "exposition-interruption-distribution") a significant correlation results so that numerous interruptions of vibration exposure should be considered as a profitable guideline for work design with respect to ergonomics.

Adult

[Performance- and strain-compensation with informatory work].

With results from literature it is shown that eye-blinking-rate is negative significant correlated with physiologic performance ability. Experiments with an abstract tracking task presented in this paper confirm that eye-blinking-rate is an indicator for activation. Taking in the indicator for activation (blinking-rate), tracking performance and central-physiological strain, phases of performance- and strain-compensation (stability, effort, fatigue, performance break-down) are defined in an hierarchical concept of stability. The compensatory processes of the human operator are discussed on the background of a stress-strain-concept taking account of the principle of feed-back.

Eyelids