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Biomedical subjects

J J Knibbe

Publications and source records attributed to J J Knibbe.

5 recordsLinked to original sources
PubMed1996

Prevalence of back pain and characteristics of the physical workload of community nurses.

A research project is described that analyses the back pain prevalence and physical working conditions of community nurses. The purpose was to compare the position of nurses working in institutional care with the specific situation of nurses working in the private homes of their patients. The results of a questionnaire showed that the back pain prevalence was relatively high as compared to other occupations and also when compared to other health care sectors. The home care organization is influenced not only by sick leave due to back pain, but also its efficiency is hampered by nurses with back pain who continue to work. It appeared that the total sick leave incidence due to musculoskeletal disorders other than back pain exceeds that due to back pain alone. The physical exposure level not only consisted of frequent and heavy lifting and transferring of patients but also a substantial static workload was present. The onset of back pain seems to result from a gradual build up of overload reaching its maximum. A preventive approach should take these differential loading factors into account. The consequences for preventive interventions are discussed resulting in recommendations towards a (participatory) ergonomic approach. This material forms the baseline of a controlled prospective trial in home care.

Adult↗
PubMed1991

Efficiency and effectiveness of stoop and squat lifting at different frequencies.

The study investigated the effects of frequency (10 and 20 lifts/min) and technique (squat and stoop) of repetitive lifting of a barbell (19 kg) on the relationship between mean power output (Pm) and energy cost in 9 male power-lifters. Oxygen uptake (VO2) was measured directly and continuously and power output was deduced from film analysis using an inverse dynamic analysis. Power output and VO2 were significantly greater for squat than for stoop lifting at the same frequency. The mechanical efficiency (ME), defined as Pm divided by the energy equivalence of VO2, increased from 12% at rate 10 to 18.5% at rate 20, but there was no significant difference between the two techniques. The effectiveness (EF), defined as the productive external power output (only work done on the barbell) divided by the energy equivalence of VO2, was significantly higher for the stoop lift than for the squat lift. EF is judged as a more useful measure than ME for characterizing the relative energy cost of a lifting task.

Adolescent↗
PubMed1990

The physical and physiological workload of refuse collectors.

In order to secure a safer and healthy work situation, the heavy physical loads imposed on 23 refuse collectors (aged 26-54) working in the city of Haarlem, in The Netherlands, were studied in a series of three experiments between 1984 and 1987. The aims were respectively (1) to study the load for workers collecting dustbins or polythene bags; (2) to introduce changes to reduce the load to avoid exceeding the overload criteria by individual refuse collectors; and (3) to investigate the effects of interventions to improve the efficiency of refuse collecting. The maximal isometric lifting force (Fmax) and the maximal aerobic power (VO2max) of 23 refuse collectors were measured in the laboratory. Fmax was measured with an isometric dynamometer pulling with one arm from the floor; the mean value was 912 (+/- 127)N. VO2max was measured running on a treadmill; the mean value was 43.3 (+/- 0.8)ml O2 per kg body mass per min. The physical load on the oxygen transport system was measured through work analysis and by a continuous registration of the heart rate over three working days. Criteria for overload were set at a mean external load of 20% Fmax and a mean energy expenditure of 30% VO2max and an energy expenditure of 50% VO2max or more for a maximum of 60 min per day. Replacement of dustbins by polythene bags resulted in a 70% increase in the total amount of refuse collected, an increase in throwing frequency, but a lower mean load per throw, and no significant differences in the mean heart rate over the working day. When polythene bags were used the mean values did not exceed the overload criteria, but 39% of the individual collectors did have a workload that was too high with respect to one of the criteria. In the last experiment the collectors were advised to reduce their work load by (a) lifting no more than two bags at a time; (b) reducing their walking pace; and (c) taking more breaks. Although compliance with the recommendations was good, and the weight lifted and the walking speed decreased, the physiological load remained the same. This may have been caused by a 15% increase in the total amount of refuse that had to be collected at that time.

Adult↗