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Evaluation of forces on the lumbosacral joint and assessment of work and energy transfers in nursing aides lifting patients
operational concept that could be embodied in a computerised support system. The recommended approach would emphasise the detection and correction of errors when they occur, in addition to the prevention of errors. 18.2.7 (101588)
Pedersen, O.M. Human risk contributions in process industry: Guides for their preidentification in well-structured activities and for post-incident analysis. Riso National Laboratory, Roskilde, Denmark, Report No RISO-M-2513, 1985, 70 pp. The report should be considered a guide for the treating of human errors: for identifying their possibilities of occurrence when designing wellstructured human tasks and for their improvement when they occur in reality. For these purposes a strong coupling between predictive and retrospective analysis is emphasised. In order to control human errors, postincident analysis of cases with human errors in a given industrial plant should be performed as means of feedback from reality for the verification of results of predictive analysis and as a general means of identifying and improving such human errors which cannot be expected to be covered by predictive analysis. 18.2.8 (101624)
Gagnon, M., Sicard, C., and Sirois, J.P. Evaluation of forces on the lumbosacral joint and assessment of work and energy transfers in nursing aides lifting patients. Ergonomics, 1986, 29.3, 407-421. Tasks associated with patient handling may present nursing aides with some risk of injuring the lumbar spine. The purpose of this study was to estimate the forces at L5/SI and to assess mechanical work and energy transfers in a task consisting of raising a patient (a 72.6 kg manikin) from a chair using three different methods: (A) with the hands; (B) with the forearms behind the patient's back at shoulder level; and (C) with a belt held at waist level. Six male subjects took part in the experiment. Spinal forces were estimated from a static and planar mathematical model used in conjunction with cinematography techniques, a force platform and EMG recordings. External forces and the internal forces (compression and shear at L5/S1) were determined from free-body diagrams and static equations. The model was analysed for its sensitivity in estimating patterns of EMG forces, intra-discal and musculo-ligamentous forces, intraabdominal pressure and inertial forces. The model was found to discriminate
166 Applied Ergonomics
June 1987
between the relative demands imposed on the spine by the different lifting methods, but the absolute values of the forces remain uncertain because of the uncertainty residing in many of the model's hypotheses. The method requiring a belt to lift the patient was found to be considerably more strenuous for the spine and also to require a larger amount of work; it should therefore not be recommended as a task for nursing aides. 18.2.9 (101626)
Patterson, P.E. The relationship between low back stress, muscle usage, and the appearance of transient load movement during manual lifting. In: IEEE 1985 Proceedings of the International Conference on Cybernetics and Society, Tucson, Arizona, USA, 1 2 - 1 5 November 1985. IEEE, New York, 1985, pp 1097--1100. Neuromuscular involvement should be considered in biomechanical evaluations of a worker's job-related stresses as a potential aid to understanding and reducing the rising incidence of low back problems in industry. Because such interactions have seldom been investigated in multisegmental movemellts, the present study was undertaken to determine the effects of the involvement of the neuromuscular system during lifting by creating conditions in which subjects had prior knowledge (PK) of a load's magnitude as well as when they had no prior knowledge (NK). Two groups of subjects, experienced and inexperienced lifters, lifted loads varying from 6-8 to 13-6 kg under both the PK and NK conditions. Results indicated that two general patterns of load movement were used by the subjects: smooth and oscillatory (irregular transient), with higher peak L4/L5 forces, and higher peak trunk moments,, found in the oscillatory pattern. The inclusion of lift preparation and load knowledge (PK and NK) considerations in training programmes and biomechanical models is recommended.
In experiments using an experienced analyst to evaluate a videotape, highly reproducible results were obtained. Furthermore, the new system required substantially less time than existing posture analysis methods to analyse and reduce postural data. 18.2.11 (101664) Froberg, J.E. Sleep deprivation and prolonged working hours. In: Hours of work: Temporal factors in work-scheduling, Edited by S. Folkard and T.H. Monk. John Wiley & Sons, Chichester, 1985, pp 6 7 - 7 5 . This paper deals with the effects oi1 performance of continuous work for 24 hours or more. Many performance functions deteriorate under such conditions, and the degree of this detrimental effect depends on a number of factors inherent in the task or situation, and on certain characteristics or attitudes of the person at work. Some of the empirical results of research in this field and on recovery from and countermeasures against performance de~line are discussed. 18.2.12 (101670) Folkard, S., and Monk, T.H. Circadian performance rhythms. In: Hours of work: Temporal factors in work-scheduling, Edited by S. Folkard and T.H. Monk. John Wiley & Sons, Chichester, 1985, pp 3 7 - 5 2 . This paper briefly reviews the evidence concerning circadian rhythms in human performance. It points to some of the problems met with in examining such rhythms, and the difficulties encountered in separating endogenous circadian rhythm effects from the masking effects of the sleepwake cycle. It is shown that the effects of time of day on performance can be fairly substantial, and that the trend over the day depends on the nature of the task under consideration. The task demands also appear to determine which oscillator is dominant in controlling performance rhythms.
18.2.10 (101643)
18.2.13 (101708)
Keyserling, W.M.
Van Der Veldt, R.J.
Postural analysis of the trunk and shoulders in simulated real time. Ergonomics, 1986, 29.4, 5 6 9 - 5 8 3 .
Looking ahead in supervisory control. In: Proceedings of the Fourth European Annual Conference on Human Decision Making and Manual Control, Zeist, The Netherlands, 2 8 - 3 0 May 1984. TNO Institute for Perception, Soesterberg, The Netherlands, 1984, pp 2 4 9 - 2 6 2 .
A new method for analysing and describing the posture of the trunk and shoulders was developed and used to describe the posture of workers performing automobile assembly operations. The system used a videotape to create a permanent record of the jobs and a personal computer to perform the clerical and time-keeping tasks associated with posture analysis.
Optimisation of the interaction between man and machine requires knowledge of human information processing. The research project discussedin this paper studies the
Pedersen, O.M. Human risk contributions in process industry: Guides for their preidentification in well-structured activities and for post-incident analysis. Riso National Laboratory, Roskilde, Denmark, Report No RISO-M-2513, 1985, 70 pp. The report should be considered a guide for the treating of human errors: for identifying their possibilities of occurrence when designing wellstructured human tasks and for their improvement when they occur in reality. For these purposes a strong coupling between predictive and retrospective analysis is emphasised. In order to control human errors, postincident analysis of cases with human errors in a given industrial plant should be performed as means of feedback from reality for the verification of results of predictive analysis and as a general means of identifying and improving such human errors which cannot be expected to be covered by predictive analysis. 18.2.8 (101624)
Gagnon, M., Sicard, C., and Sirois, J.P. Evaluation of forces on the lumbosacral joint and assessment of work and energy transfers in nursing aides lifting patients. Ergonomics, 1986, 29.3, 407-421. Tasks associated with patient handling may present nursing aides with some risk of injuring the lumbar spine. The purpose of this study was to estimate the forces at L5/SI and to assess mechanical work and energy transfers in a task consisting of raising a patient (a 72.6 kg manikin) from a chair using three different methods: (A) with the hands; (B) with the forearms behind the patient's back at shoulder level; and (C) with a belt held at waist level. Six male subjects took part in the experiment. Spinal forces were estimated from a static and planar mathematical model used in conjunction with cinematography techniques, a force platform and EMG recordings. External forces and the internal forces (compression and shear at L5/S1) were determined from free-body diagrams and static equations. The model was analysed for its sensitivity in estimating patterns of EMG forces, intra-discal and musculo-ligamentous forces, intraabdominal pressure and inertial forces. The model was found to discriminate
166 Applied Ergonomics
June 1987
between the relative demands imposed on the spine by the different lifting methods, but the absolute values of the forces remain uncertain because of the uncertainty residing in many of the model's hypotheses. The method requiring a belt to lift the patient was found to be considerably more strenuous for the spine and also to require a larger amount of work; it should therefore not be recommended as a task for nursing aides. 18.2.9 (101626)
Patterson, P.E. The relationship between low back stress, muscle usage, and the appearance of transient load movement during manual lifting. In: IEEE 1985 Proceedings of the International Conference on Cybernetics and Society, Tucson, Arizona, USA, 1 2 - 1 5 November 1985. IEEE, New York, 1985, pp 1097--1100. Neuromuscular involvement should be considered in biomechanical evaluations of a worker's job-related stresses as a potential aid to understanding and reducing the rising incidence of low back problems in industry. Because such interactions have seldom been investigated in multisegmental movemellts, the present study was undertaken to determine the effects of the involvement of the neuromuscular system during lifting by creating conditions in which subjects had prior knowledge (PK) of a load's magnitude as well as when they had no prior knowledge (NK). Two groups of subjects, experienced and inexperienced lifters, lifted loads varying from 6-8 to 13-6 kg under both the PK and NK conditions. Results indicated that two general patterns of load movement were used by the subjects: smooth and oscillatory (irregular transient), with higher peak L4/L5 forces, and higher peak trunk moments,, found in the oscillatory pattern. The inclusion of lift preparation and load knowledge (PK and NK) considerations in training programmes and biomechanical models is recommended.
In experiments using an experienced analyst to evaluate a videotape, highly reproducible results were obtained. Furthermore, the new system required substantially less time than existing posture analysis methods to analyse and reduce postural data. 18.2.11 (101664) Froberg, J.E. Sleep deprivation and prolonged working hours. In: Hours of work: Temporal factors in work-scheduling, Edited by S. Folkard and T.H. Monk. John Wiley & Sons, Chichester, 1985, pp 6 7 - 7 5 . This paper deals with the effects oi1 performance of continuous work for 24 hours or more. Many performance functions deteriorate under such conditions, and the degree of this detrimental effect depends on a number of factors inherent in the task or situation, and on certain characteristics or attitudes of the person at work. Some of the empirical results of research in this field and on recovery from and countermeasures against performance de~line are discussed. 18.2.12 (101670) Folkard, S., and Monk, T.H. Circadian performance rhythms. In: Hours of work: Temporal factors in work-scheduling, Edited by S. Folkard and T.H. Monk. John Wiley & Sons, Chichester, 1985, pp 3 7 - 5 2 . This paper briefly reviews the evidence concerning circadian rhythms in human performance. It points to some of the problems met with in examining such rhythms, and the difficulties encountered in separating endogenous circadian rhythm effects from the masking effects of the sleepwake cycle. It is shown that the effects of time of day on performance can be fairly substantial, and that the trend over the day depends on the nature of the task under consideration. The task demands also appear to determine which oscillator is dominant in controlling performance rhythms.
18.2.10 (101643)
18.2.13 (101708)
Keyserling, W.M.
Van Der Veldt, R.J.
Postural analysis of the trunk and shoulders in simulated real time. Ergonomics, 1986, 29.4, 5 6 9 - 5 8 3 .
Looking ahead in supervisory control. In: Proceedings of the Fourth European Annual Conference on Human Decision Making and Manual Control, Zeist, The Netherlands, 2 8 - 3 0 May 1984. TNO Institute for Perception, Soesterberg, The Netherlands, 1984, pp 2 4 9 - 2 6 2 .
A new method for analysing and describing the posture of the trunk and shoulders was developed and used to describe the posture of workers performing automobile assembly operations. The system used a videotape to create a permanent record of the jobs and a personal computer to perform the clerical and time-keeping tasks associated with posture analysis.
Optimisation of the interaction between man and machine requires knowledge of human information processing. The research project discussedin this paper studies the