- Email: [email protected]
Maximum weights of lift acceptable to male and female industrial workers for extended work shifts
16.4.7 (90105)
Craig, A., and Condon, R. Operational efficiency and time of day. Human Factors, 1984, 26.2, 197-205. Forty-eight subjects performed a battery of six predominantly perceptual tasks that were relevant to bridge operations on a ship at sea. Sessions were run at six times over an extended waking day, between 08.00 and midnight. For some of the tasks performance was noticeably deficient at certain times of day, the diurnal pattern corresponding approximately with that in activation and alertness. However, closer examination of the data reveals that although a genuine efficiency deficit may exist at particular times, a major part of the variation in performance can reasonably be attributed to a shift in the trade-off between speed and accuracy. Because the direction of the shift is towards faster but less careful performance as the day progresses, the shift may be due to accumulating fatigue rather than to time of day per se. Regardless of the primary cause, vulnerability may be increased at certain times due to a slump in operational efficiency.
Physiology, anthropometry and biomechanics 16.4.8 (90133) Yamana, N., et al The body form of pregnant women in monthly transitions. (In Japanese.) Japanese Journal o f Ergonomics, 1984, 20.3,171-178. One thousand measurements were made on 520 pregnant women to obtain basic data for designing maternity clothes. Pregnant women, from the 2nd to the 10th month of their pregnancy, were measured once or more on 44 items. Items such as depth and girth of abdomen and waist showed a remarkable change, as well as linear increase after the 4th month of pregnancy. But items concerning height showed no change. Principal components analysis revealed the body form of pregnant women can be estimated by the following three principal components. The first, size factor, represents the size of the body. The second, shape factor, represents the degree of obesity. The third represents the characteristics of the body trunk of pregnant women. The scores of the first principal component increase linearly and the scores of the second and the third decrease linearly with the progress of each month of pregnancy. Accordingly, the size of maternity clothes cannot be determined by month
of pregnancy. They must be designed for a variety of sizes and body shapes, changing with the progress of each month of pregnancy. 16.4.9 (90132)
Courtney, A.J. Hand anthropometry of Hong Kong Chinese females compared to other ethnic groups. Ergonomics, 1984, 27.11, 1169-1180. An anthropometric study of the hand dimensions of Hong Kong Chinese female workers was carried out using 100 subjects. Twenty-three hand dimensions were measured and compared with data from the UK, Japan and the USA. The Hong Kong Chinese had overan smaller hands than the UK and the USA females and larger hands than Japanese females. Comparisons were also made between the Hong Kong Chinese and UK females on the basis of age and ethnic group. In every case where a significant difference occurred the Hong Kong females had shorter, narrower hands with longer fingers than all other groups. 16.4.10 (90146) Karwowski, W., and Ayoub, M.M. Effect of frequency on the maximum acceptable weight of lift. In:Proceedings of the 1st Mid-Central Ergonomics/ Human-Factors Conference, Cincinnati, Ohio, April 12-13, 1984, Edited by A. Mital, pp 113-118. A psychophysical experiment was carried out to determine the maximum acceptable weight for lifting from floor to the 0.76 mlevel. A total of 108 data points were collected. Average loads of 44.77, 29-93, 19"93 and 15"06 kg were lifted for frequencies of 0-1, 3, 9, and 12 l/fts/min, respectively. The metabolic energy expenditure and heart rates at high frequencies of lift indicated that the period of 40 min may not be sufficiently long to determine the 'true' maximum acceptable weight for an 8 h shift.
16.4.11 (90150) Mital, A. M a x i m u m weights of liftacceptable to male and female industrial workers for extended work shifts. Ergonomics, 1984, 27.11, 1115-1126. This paper reports the development of maximum acceptable weight of lift databases for male and female industrial workers for 12 h work periods. Using a psychophysical methodology, 37 males and 37 females, experienced in manual lifting, performed various lifting tasks involving four frequencies, three box sizes, and three height levels. The maximum acceptable weight of lift was significantly influenced by the
frequency of lift, height of lift, and box size. Box size effects were, however, less profound than frequency, and height effects. The maximum weight, acceptable for 12 h of lifting, elicited an average heart rate of 90 and 101 beats/min for males and females, respectively. Males selected weights that, on average, resulted in metabolic energy expenditure rates of 23% of their aerobic capacity for 12 h of lifting. Females required metabolic energy expenditure rates equivalent to 24% of their aerobic capacity for lifting acceptable levels of weight for 12 h.
16.4.12 (90151) Mital, A. Comprehensive m a x i m u m acceptable weight of liftdatabase for regular 8 hour work shifts.Ergonomics, 1984, 27.1 I, 1127-I 138. This paper presents comprehensive maximum acceptable weight of lift data for male and female industrial workers for 8 h shifts. The experimental data collected in this study, for 8 h, were compared with previous studies of Snook (1978) and Ayoub et al (1978). Since data from all three studies compared favourably, they were integrated to develop comprehensive databases. 16.4.13 (90153)
Mueller, M.R., and Bhattacharya, A. A study of postural changes associated with carpet installation. In: Proceedings of the 1st Mid-Central Ergonomics/ Human-Factors Conference, Cincinnati, Ohio, April 12-13, 1984, Edited by A. Mital, pp 14-19. Information about carpet layers and other trades that require extensive kneeling shows higher knee morbidity ratios than those trades which require limited or no kneeling (Tanaka et al, 1982). In addition, tranmatogenic factors associated .with carpet layers, including impact force, repetition of impact force and postures, have been shown to be biomechanically demanding to the knee and other body joints leading to possible knee morbidity, and other joint dysfunctions. In a recent study by Bhattacharya, et al (in review) showed carpet layers spend 75% of their work period kneeling, and when carpet is being stretched, 71% of their time is spent u~ng the knee-kicker. They also found that the hard kick average impact force value was 3200 N, and the rate of application of the kick was about 132 kicks per hour. The focus of the present study was to determine the range of joint angles as the worker progresses through the knee-kicking cycle. In addition, data were obtained concerning reaction forces and muscle moments at the body joints, and ground reaction
Applied Ergonomics
December 1985
301
Craig, A., and Condon, R. Operational efficiency and time of day. Human Factors, 1984, 26.2, 197-205. Forty-eight subjects performed a battery of six predominantly perceptual tasks that were relevant to bridge operations on a ship at sea. Sessions were run at six times over an extended waking day, between 08.00 and midnight. For some of the tasks performance was noticeably deficient at certain times of day, the diurnal pattern corresponding approximately with that in activation and alertness. However, closer examination of the data reveals that although a genuine efficiency deficit may exist at particular times, a major part of the variation in performance can reasonably be attributed to a shift in the trade-off between speed and accuracy. Because the direction of the shift is towards faster but less careful performance as the day progresses, the shift may be due to accumulating fatigue rather than to time of day per se. Regardless of the primary cause, vulnerability may be increased at certain times due to a slump in operational efficiency.
Physiology, anthropometry and biomechanics 16.4.8 (90133) Yamana, N., et al The body form of pregnant women in monthly transitions. (In Japanese.) Japanese Journal o f Ergonomics, 1984, 20.3,171-178. One thousand measurements were made on 520 pregnant women to obtain basic data for designing maternity clothes. Pregnant women, from the 2nd to the 10th month of their pregnancy, were measured once or more on 44 items. Items such as depth and girth of abdomen and waist showed a remarkable change, as well as linear increase after the 4th month of pregnancy. But items concerning height showed no change. Principal components analysis revealed the body form of pregnant women can be estimated by the following three principal components. The first, size factor, represents the size of the body. The second, shape factor, represents the degree of obesity. The third represents the characteristics of the body trunk of pregnant women. The scores of the first principal component increase linearly and the scores of the second and the third decrease linearly with the progress of each month of pregnancy. Accordingly, the size of maternity clothes cannot be determined by month
of pregnancy. They must be designed for a variety of sizes and body shapes, changing with the progress of each month of pregnancy. 16.4.9 (90132)
Courtney, A.J. Hand anthropometry of Hong Kong Chinese females compared to other ethnic groups. Ergonomics, 1984, 27.11, 1169-1180. An anthropometric study of the hand dimensions of Hong Kong Chinese female workers was carried out using 100 subjects. Twenty-three hand dimensions were measured and compared with data from the UK, Japan and the USA. The Hong Kong Chinese had overan smaller hands than the UK and the USA females and larger hands than Japanese females. Comparisons were also made between the Hong Kong Chinese and UK females on the basis of age and ethnic group. In every case where a significant difference occurred the Hong Kong females had shorter, narrower hands with longer fingers than all other groups. 16.4.10 (90146) Karwowski, W., and Ayoub, M.M. Effect of frequency on the maximum acceptable weight of lift. In:Proceedings of the 1st Mid-Central Ergonomics/ Human-Factors Conference, Cincinnati, Ohio, April 12-13, 1984, Edited by A. Mital, pp 113-118. A psychophysical experiment was carried out to determine the maximum acceptable weight for lifting from floor to the 0.76 mlevel. A total of 108 data points were collected. Average loads of 44.77, 29-93, 19"93 and 15"06 kg were lifted for frequencies of 0-1, 3, 9, and 12 l/fts/min, respectively. The metabolic energy expenditure and heart rates at high frequencies of lift indicated that the period of 40 min may not be sufficiently long to determine the 'true' maximum acceptable weight for an 8 h shift.
16.4.11 (90150) Mital, A. M a x i m u m weights of liftacceptable to male and female industrial workers for extended work shifts. Ergonomics, 1984, 27.11, 1115-1126. This paper reports the development of maximum acceptable weight of lift databases for male and female industrial workers for 12 h work periods. Using a psychophysical methodology, 37 males and 37 females, experienced in manual lifting, performed various lifting tasks involving four frequencies, three box sizes, and three height levels. The maximum acceptable weight of lift was significantly influenced by the
frequency of lift, height of lift, and box size. Box size effects were, however, less profound than frequency, and height effects. The maximum weight, acceptable for 12 h of lifting, elicited an average heart rate of 90 and 101 beats/min for males and females, respectively. Males selected weights that, on average, resulted in metabolic energy expenditure rates of 23% of their aerobic capacity for 12 h of lifting. Females required metabolic energy expenditure rates equivalent to 24% of their aerobic capacity for lifting acceptable levels of weight for 12 h.
16.4.12 (90151) Mital, A. Comprehensive m a x i m u m acceptable weight of liftdatabase for regular 8 hour work shifts.Ergonomics, 1984, 27.1 I, 1127-I 138. This paper presents comprehensive maximum acceptable weight of lift data for male and female industrial workers for 8 h shifts. The experimental data collected in this study, for 8 h, were compared with previous studies of Snook (1978) and Ayoub et al (1978). Since data from all three studies compared favourably, they were integrated to develop comprehensive databases. 16.4.13 (90153)
Mueller, M.R., and Bhattacharya, A. A study of postural changes associated with carpet installation. In: Proceedings of the 1st Mid-Central Ergonomics/ Human-Factors Conference, Cincinnati, Ohio, April 12-13, 1984, Edited by A. Mital, pp 14-19. Information about carpet layers and other trades that require extensive kneeling shows higher knee morbidity ratios than those trades which require limited or no kneeling (Tanaka et al, 1982). In addition, tranmatogenic factors associated .with carpet layers, including impact force, repetition of impact force and postures, have been shown to be biomechanically demanding to the knee and other body joints leading to possible knee morbidity, and other joint dysfunctions. In a recent study by Bhattacharya, et al (in review) showed carpet layers spend 75% of their work period kneeling, and when carpet is being stretched, 71% of their time is spent u~ng the knee-kicker. They also found that the hard kick average impact force value was 3200 N, and the rate of application of the kick was about 132 kicks per hour. The focus of the present study was to determine the range of joint angles as the worker progresses through the knee-kicking cycle. In addition, data were obtained concerning reaction forces and muscle moments at the body joints, and ground reaction
Applied Ergonomics
December 1985
301