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Relative stresses of wheelchair activity
fatigue; the results of measurements taken after working for some hours, of some of the visual functions showed an impairment compared with the results before working. The amount of this impairment is closely related to the extent of the working period. 12.1.13 (79360) Meyer, J.J., et al Some aspects of visual strain in workplaces with CRT display terminals (Quelques Aspects de la Charge Visuelle aux Postes de Travail Impliquant un Ecran de Visualisation). (In French.) Travail Humain, 1979, 42.2, 275-301. A detailed analysis of the conditions of use of CRTs suggests that they are not comparable with those of other known situations for which the criteria defining visual capabilities and lighting standards have already been established. Too low levels of luminance, uneven symbols often badly focused, flickering and appearing in negative contrast due to unusual time patterns; phenomena of simultaneous and successive glare and finally little possibility of regulating distance, luminance and contrast, convey the following hypothesis: (a) the search of images, their focussing and their integration become an actual performance, for which cost must be assessed, in the usually allotted time limits for writing, reading and control; (b) widely spread small functional defects become a problem, whereas in other situations they can be considered as physiological because of their compensation through adaptation. It is obvious to the authors that a visual overload exists even if it cannot yet be evaluated completely for lack of adequate instruments independently from the fact that many other elements constituting nervous and physiological stress specific to the new work process can add to it. Possible improvements of the situation are discussed. 12.1.14 (79361)
Reading, V.M. Eyestrain and reading from a screen. Reprographics Quarterly, 1979, 12.4, 113-116. VDUs or readers are not considered to be in any way visually harmful. In general, front projection readers were preferred. The phenomenon of eyestrain is defined. The main causes of this are ocular factors such as uncorrected sight defects or
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environmental factors such as low screen luminance or glare. Lack of ergonomics design for workstations can also cause postural discomfort. 12.1.15 (79362) Tikkanen, K.T. Spectral eye fatigue in a school environment. Lighting Research and Technology, 1979, 11.4, 184-188. The eye fatigue information was expressed in writing by a randomly selected group of pupils in five Swedish comprehensive schools in winter and in spring. Simultaneous measurements of mixed electric light and daylight were made of spectral power distribution and illuminance at the classroom centre at pupil desk height. It is concluded that in this northern classroom environment of mixed electric light and daylight, the expressed eye fatigue was significantly higher in the experimental schools with mere skylight (monitor) windows as compared with the control schools with the regular side-view windows at eye-level height at sitting position. Also this fatigue was significantly higher among boys than among girls in classrooms with monitor windows as the only source of daylight and view. In a mild climate, this type of expressed eye fatigue was almost nonexistent even in windowless schools and was totally non-existent in schools with side-view windows.
Physiology, anthropometry and biomechanics 12.1.16 (79398) Glaser, R.M., et al Relative stresses of wheelchair activity. Human Factors, Apr 1980, 22.2, 177-181. To study relative stresses of wheelchair activity, seven able-bodied subjects' metabolic (oxygen uptake) and cardiopulmonary (heart rate and pulmonary ventilation) responses were determined during wheelchair (arm stroking) and bicycle (leg pedalling) exercise at identical propulsion velocities and work rates. For this, subjects exercised on a combination wheelchair-bicycle ergometer at wheel velocities of 1.17, 2'34 and 3"51 km/h. The six bouts of exercise were intermittent - 5 min exercise periods interspersed by 10 min rest periods. At 1"17 km/h no significant differences were found between wheelchair and bicycle exercise for each of the monitored variables. At 2.34 and 3'51 km/h, however, all responses were significantly higher for wheelchair exercise. At these higher
Applied Ergonomics March 1981
velocities, calculated respiratory exchange ratio and ventilatory equivalent values were also significantly higher for wheelchair exercise. These results suggest that acute exposure to wheelchair activity could be relatively stressful and could limit rehabilitative efforts, 12.1.17 (79399)
Nag, P.K., and Datt, P. Effectiveness of some simple agricultural weeders with reference to physiological responses. Journal of Human Ergology, Sep 1979, 8.1, 13-21 Seven different weeders used in agricultural operations were studied with reference to physiological responses and area weeded per unit time by using each method, and manual weeding. Five young skilled agricultural workers were used for the study. Average work pulse rate varied from 105 to 120 beats/min in weeding operations using blade-, and rake-type, projection finger-type and double sweep-type weeders. The lowest cardiac response was observed with the wheel hoe-type weeder. Blood pressure responses were also higher with the other three weeders mentioned above. Pulmonary demand was around 27 £/min with all the weeders; but the highest oxygen uptake (56% of the maximimal oxygen uptake) occurred in the case of a projection finger-type weeder. The maximum area was weeded (1"42 m2/min) by the wheel hoe-type weeder. Comparing physiological demand, work performance and preference of the workers, the wheel hoe-type of weeder was found to be the best for Indian workers. 12.1.18 (79425)
Davies, B.T., et aI A comparison of hand anthropometry of females in three ethnic groups. Ergonomics, Feb 1980, 23.2, 179-182. An anthropometric study of female workers' hand dimensions was carried out using 92 subjects. Three ethnic groups, Western Europeans, Indian and West Indian were identified and compared. There were no significant differences between West Indian and Indian and West Indian and European groups. Fifty-one West Europeans, 21 Indians (from the Punjab) and 20 West Indians were included in the study. 12.1.19 (79437)
Jones, D.F. The choice is up to you! Dynacopics Inc, Don Mills, Ontario, Canada, 1979, 67 pp. Back pain is a universal problem. Until recently, it was assumed that evolution had not caught up to our
Reading, V.M. Eyestrain and reading from a screen. Reprographics Quarterly, 1979, 12.4, 113-116. VDUs or readers are not considered to be in any way visually harmful. In general, front projection readers were preferred. The phenomenon of eyestrain is defined. The main causes of this are ocular factors such as uncorrected sight defects or
48
environmental factors such as low screen luminance or glare. Lack of ergonomics design for workstations can also cause postural discomfort. 12.1.15 (79362) Tikkanen, K.T. Spectral eye fatigue in a school environment. Lighting Research and Technology, 1979, 11.4, 184-188. The eye fatigue information was expressed in writing by a randomly selected group of pupils in five Swedish comprehensive schools in winter and in spring. Simultaneous measurements of mixed electric light and daylight were made of spectral power distribution and illuminance at the classroom centre at pupil desk height. It is concluded that in this northern classroom environment of mixed electric light and daylight, the expressed eye fatigue was significantly higher in the experimental schools with mere skylight (monitor) windows as compared with the control schools with the regular side-view windows at eye-level height at sitting position. Also this fatigue was significantly higher among boys than among girls in classrooms with monitor windows as the only source of daylight and view. In a mild climate, this type of expressed eye fatigue was almost nonexistent even in windowless schools and was totally non-existent in schools with side-view windows.
Physiology, anthropometry and biomechanics 12.1.16 (79398) Glaser, R.M., et al Relative stresses of wheelchair activity. Human Factors, Apr 1980, 22.2, 177-181. To study relative stresses of wheelchair activity, seven able-bodied subjects' metabolic (oxygen uptake) and cardiopulmonary (heart rate and pulmonary ventilation) responses were determined during wheelchair (arm stroking) and bicycle (leg pedalling) exercise at identical propulsion velocities and work rates. For this, subjects exercised on a combination wheelchair-bicycle ergometer at wheel velocities of 1.17, 2'34 and 3"51 km/h. The six bouts of exercise were intermittent - 5 min exercise periods interspersed by 10 min rest periods. At 1"17 km/h no significant differences were found between wheelchair and bicycle exercise for each of the monitored variables. At 2.34 and 3'51 km/h, however, all responses were significantly higher for wheelchair exercise. At these higher
Applied Ergonomics March 1981
velocities, calculated respiratory exchange ratio and ventilatory equivalent values were also significantly higher for wheelchair exercise. These results suggest that acute exposure to wheelchair activity could be relatively stressful and could limit rehabilitative efforts, 12.1.17 (79399)
Nag, P.K., and Datt, P. Effectiveness of some simple agricultural weeders with reference to physiological responses. Journal of Human Ergology, Sep 1979, 8.1, 13-21 Seven different weeders used in agricultural operations were studied with reference to physiological responses and area weeded per unit time by using each method, and manual weeding. Five young skilled agricultural workers were used for the study. Average work pulse rate varied from 105 to 120 beats/min in weeding operations using blade-, and rake-type, projection finger-type and double sweep-type weeders. The lowest cardiac response was observed with the wheel hoe-type weeder. Blood pressure responses were also higher with the other three weeders mentioned above. Pulmonary demand was around 27 £/min with all the weeders; but the highest oxygen uptake (56% of the maximimal oxygen uptake) occurred in the case of a projection finger-type weeder. The maximum area was weeded (1"42 m2/min) by the wheel hoe-type weeder. Comparing physiological demand, work performance and preference of the workers, the wheel hoe-type of weeder was found to be the best for Indian workers. 12.1.18 (79425)
Davies, B.T., et aI A comparison of hand anthropometry of females in three ethnic groups. Ergonomics, Feb 1980, 23.2, 179-182. An anthropometric study of female workers' hand dimensions was carried out using 92 subjects. Three ethnic groups, Western Europeans, Indian and West Indian were identified and compared. There were no significant differences between West Indian and Indian and West Indian and European groups. Fifty-one West Europeans, 21 Indians (from the Punjab) and 20 West Indians were included in the study. 12.1.19 (79437)
Jones, D.F. The choice is up to you! Dynacopics Inc, Don Mills, Ontario, Canada, 1979, 67 pp. Back pain is a universal problem. Until recently, it was assumed that evolution had not caught up to our