Biomedical subjects

W Laurig

Publications and source records attributed to W Laurig.

16 recordsLinked to original sources

PubMed1992

Logistical and ergonomic transportation capacity for refuse collection workers: a work physiology field study.

In a work physiology field study, the work flow and the electrocardiogram were recorded throughout whole shifts for six male refuse (garbage) collection workers who transported and emptied 1.1 m3 refuse containers. The work rate (WR), indicated by the number of 1.1 m3 containers emptied per unit of time, and the work pulse rate (WPR) were determined in the data evaluation. The work pulse rate increases with the work rate. The functional relationship can be approximated by a linear regression function (WPR = 20.9 + 35.8.WR). The work pulse rate reaches such high values that it must be assumed that the work cannot be performed continuously throughout the whole working day. Consequently, regular breaks should be provided. When determining the necessary duration of the breaks, it was assumed that an equilibrium between fatigue and recovery should be maintained during the working day. The recovery breaks should be at least long enough for the heart rate to return to the resting level. The necessary duration of the breaks was determined on the basis of the present field study and the laboratory investigations described in the literature. A minimum duration of 10 min per working hour results from the calculations. The breaks should be taken regularly at about hourly intervals. A transportation-capacity model is provided for the planning of the deployment of refuse workers. It permits calculation of the number of 1.1 m3 containers a three-man crew, comprising the refuse collection truck driver and two loaders, can empty during one shift. Both the logistical and ergonomic transportation capacities can be determined using the model. The logistical transportation capacity (TCL) indicates the number of containers which can be emptied per shift by a crew when only criteria such as the optimal utilization of the working time are considered. The ergonomic transportation capacity (TCE) is understood as the number of containers which can be emptied per shift taking into consideration the workers' strain and the recovery breaks they require. TCE amounts to between about 140 and 160 containers per shift depending on the type of city district. TCL is higher by between 20 and 30 containers per shift. In order to meet the demand of protecting workers' health, the number of containers to be emptied per shift by a three-man crew should not exceed the ergonomic transportation capacity.

Adult↗

PubMed1990

[Stress-strain approach--a principle for ergonomic studies].

In the terminology of occupational hygiene and the WAO no distinction has been made to date between "load" and "strain". Occupational medicine and ergonomics by contrast, in addition to differentiating between the terms, have been developing the "load-strain approach" since about 1970. After outlining the historical development of the terms and explaining them, the approach is derived and presented in a simple and extended form. Starting from demands made by the WAO, the significance of the approach for the planning and execution of ergonomic investigations is explained. In the approach differentiation between the "description", "assessment" and "judgement" of working conditions is recommended. Possible approaches and criteria for forming a judgment are presented and discussed, with special attention being paid to models for the operationalization of strain. A concept for pragmatic judgment is presented after discussion about the necessity, frequently encountered in practice, of balancing the demands of providing scientific proof and of arriving at decisions relevant to practical problems.

Ergonomics↗

PubMed1990

[The load on the spinal column in handling of burdens].

The health consequences of long-term professional activity in loading for transport were investigated in an epidemiological study. This involved determining the frequency of orthopedic diseases within a series of transport workers and comparing it with the disease frequency in a comparable group with the same age distribution. The frequency of orthopedic diseases in transport workers is about 22% higher than in the other group. Most of the findings relate to the lower lumbar spine. An increase in the number of diseases can be observed in the transport workers even after a short period of professional activity. In order to examine the possible cause for the increased frequency of disease, the load on the lower lumbar spine was determined quantitatively using biomechanical model calculations. A three-dimensional biomechanical model that allows examination of both static and dynamic load was developed for this purpose. The influence of posture, the mass of the load to be transferred, and the acceleration of the load and the body on the mechanical spinal load were examined as typical examples of load manipulation. In the assessment of load, the compressive forces calculated were compared with the strength of the spinal elements. The compression forces on the lower lumbar spine are of the same order of magnitude as the strength. The high mechanical load can therefore be regarded as a possible cause of the high frequency of disease among persons whose professional activity involves lifting heavy loads.

Adult↗

PubMed1988

Orthopaedic diseases among transport workers.

Material handling tasks result in high load on the skeletal system. Long-term employment in transportation jobs may therefore cause a high frequency of orthopaedic diseases, particularly in the spinal region. An epidemiological study was performed on employees from a large company in order to test this hypothesis. The medical history of 249 male transport workers was examined by means of statistical analysis of the orthopaedic diseases documented in the record file of their company's health service. For purposes of comparison, the same data evaluation was performed for an age-matched reference group consisting of 267 persons chosen randomly from among the male employees in the same company. The proportion of persons with orthopaedic diseases amounts to 77.1% among the transport workers and 62.9% among the reference persons. It is consequently 1.22 times higher for the transport workers than for the reference persons ("rate ratio RR" = 1.22). The greatest part of all orthopaedic diseases affects the spine. Within the spine, the lumbar region is the most frequently damaged. Both for the totality of all spinal sections as well as for diseases of particular spinal sections (cervical, thoracic, lumbar spine), the proportion of the transport workers with diseases is higher than that of the reference persons (RR between 1.20 and 1.36). The proportion of persons with spinal diseases increases with age in both groups. There is no observable difference between the groups with regard to the frequency of persons with degenerative diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986