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Biomedical subjects

A M Genaidy

Publications and source records attributed to A M Genaidy.

At least 37 records · Page 2Linked to original sources
PubMed1991

Truncal flexibility exercise effects on musculoskeletal capability for manual handling operations.

The main purpose of this study was to investigate the effects of a truncal flexibility programme on manual material handling strength and endurance, low-back flexibility and truncal rotation. Two training groups (males and females) and one control group participated in the study. Multivariate analysis of variance and discriminant analysis suggested that it is possible to improve significantly dynamic muscular strength, low-back flexibility and truncal rotation during the course of the exercises described in this investigation. However, the effects of the programme on muscular endurance were mixed; females significantly improved and males did not. The response variables collected for the control group did not show any significant change over the study period. The implications of the results with respect to the industrial environment are discussed.

Journal Article↗
PubMed1991

A training programme to improve human physical capability for manual handling jobs.

The primary objectives of this study were to test whether the muscular endurance, muscular strength, cardiovascular endurance, and workload perception of individuals engaged in combined manual handling tasks could be improved through a short and intensive physical training programme. Two separate experiments were conducted to achieve the objectives of this study. The independent variables studied in each experiment were group type (training and control) and training session. Twenty male subjects participated in these experiments. The task performed in the first experiment was a combined lifting, lowering, pushing, pulling, and carrying activity. The second experiment featured an upper extremity manual handling task. Results indicated that, for both experiments, endurance time increased and heart rate decreased significantly during the course of training. For experiment 1, there were no significant changes in either static or dynamic strength with training. On the other hand, significant increases in static and dynamic strength were observed with the training group of experiment 2. The results of this study suggest that it is possible to improve muscular endurance and cardiovascular endurance with a short and intensive training programme. Moreover, an endurance training programme may increase both static and dynamic strength only if the weight of load handled during the training programme taxes the subject to 50% or more of his/her initial dynamic strength.

Adult↗
PubMed1991

Endurance time and physiological responses to prolonged arm lifting.

The main objective of this study was to examine the effects of prolonged arm lifting tasks on endurance time and physiological responses. Ten male college students participated in the study. The independent variables were the frequency of handling and weight of load. The dependent variables were endurance time, oxygen consumption, minute ventilation, heart rate, and ratings of perceived exertion of the shoulder, arm, back, leg and overall body. The results indicated that: (1) endurance time decreased with an increase in frequency or load; (2) oxygen consumption and heart rate limits were dependent on the interaction of frequency and load; (3) oxygen consumption and heart rate limits for arm lifting were generally lower than limits for leg lifting tasks; and (4) for arm work, average physiological responses recorded over short durations were not significantly different from those based on long durations.

Adult↗
PubMed1990

Physiological and psychophysical responses to static, dynamic and combined arm tasks.

The main objective of the present study was to determine the effects of arm tasks possessing varying degrees of static and dynamic components upon the physiological and psychophysical strain imposed on the human body. Heart rate and blood pressure were used as indices of cardiovascular strain, while ratings of perceived exertion and endurance time are used as indices of psychophysical strain. For each weight of load studied, static tasks recorded the highest systolic blood pressure, dyastolic pressure, and ratings of perceived exertion values followed by combined, then highly dynamic, tasks. The highly dynamic task recorded the highest endurance time followed by combined then purely static tasks. This study supports the idea that blood pressure should be incorporated as one of the monitored strain factors in setting criteria for manual materials-handling tasks. In addition, the ratings of perceived exertion can be used as an effective tool in assessing the static component of the task. Based on the results obtained from the experimental conditions studied, the weight of the load has been shown to be an important parameter in the design of arm tasks comprising varying degrees of static and dynamic components. On the other hand, the frequency of handling is not an important parameter in the design of these types of tasks.

Journal Article↗
PubMed1990

Psychophysical models for manual lifting tasks.

This paper provides two models for males and females to assess the psychophysical maximum acceptable weight of lift. The weight guidelines generated by the models are a function of lifting frequency, height of lift, sagittal or asymmetrical lifting, task duration, container size in the sagittal plane, presence or absence of container couplings, and percentage of the working population. The developed models were generated from a knowledge base available in the published literature. A computer program was written in BASIC to assist the user in determining the safe load that could be handled by a specified working population. Model validation showed that the models developed predict the maximum acceptable weight of lift with a reasonable degree of accuracy. A comparison between the National Institute for Occupational Safety and Health recommendations and those made on the basis of the models developed in this paper is also presented.

Journal Article↗
PubMed1990

Improving human capabilities for combined manual handling tasks through a short and intensive physical training program.

The primary objectives of this study were to test whether the muscular endurance, muscular strength, cardiovascular endurance, and workload perception of individuals engaged in combined manual handling tasks could be improved through a short and intensive physical training program. Three groups were formed to achieve the objectives of this study, and five subjects participated in each group. Two groups were trained using the concept of progressive resistance exercise; one group used the concept of six-repetition maximum (6 RM) while the other group followed the ten-repetition maximum (10 RM) protocol. The third group was used as a control group to monitor the effectiveness of the training groups. The training groups required subjects' attendance at 16 sessions for a period of 6 weeks. The control group performed the same tests given to the training group twice, separated by a period of 6 weeks. Endurance time, heart rate, ratings of perceived exertion, and static and dynamic strength were the response variables. Based on the results of this study, the following conclusions could be made: (1) it is possible to significantly improve muscular endurance, muscular strength, and cardiovascular endurance through the short and intensive training protocols examined in this investigation (the 10 RM training protocol, however, yielded better improvement in human physical capability than the 6 RM training protocol); and (2) for a fixed work load, endurance time can increase without changing job demand perception.

Adult↗
PubMed1990

A muscular endurance training program for symmetrical and asymmetrical manual lifting tasks.

The purpose of this study was to test whether the endurance limits of new employees engaged in symmetrical and asymmetrical manual lifting tasks can be significantly increased through a physical training program. Each subject participating in the training program performed a total of 16 sessions. A control group performed two sessions separated by a 4-week interval. The results of this study showed that endurance time increased by 248% for the symmetrical and 46% for the asymmetrical lifting tasks. Furthermore, the frequency of handling increased by 44% and 34% for these tasks, respectively. The control group showed no improvement in terms of endurance time and frequency of handling. The implementation of a physical training program as a tool to control overexertion injuries in industrial settings is outlined.

Accidents, Occupational↗
PubMed1989

Portability of three consumer products.

Three consumer products (a television set, a personal computer and a typewriter), all considered portable by their respective manufacturers, were evaluated experimentally for portability. Products were not considered portable if the physical and subjective workloads resulting from carrying them over specified distances were excessive. Twenty-two males and six females participated in the experimental investigation and carried the three products for distances of 45.72, 91.44. 137.16 and 182.88 m. Their pulse and ratings of perceived exertion (RPE) of the arms and whole body were recorded and used as measures of physical and perceived workloads. Both physiological and subjective responses to carrying products were significantly influenced by the type of product and carrying distance, regardless of the gender of the person performing the carrying. The results of this study and the design guidelines provided in the literature for one-handed and two-handed carrying tasks led to the conclusion that, of the three products, only the television set could be considered portable.

Journal Article↗
PubMed1989

Effects of frequency and load to lift on endurance time.

The purpose of the present study was to determine endurance time for manual lifting tasks which were performed over a wide range of loads (5, 10, 15, and 20 kg) and frequencies (4, 6, 8, and 10 times/min) for a lift from floor to table height. Endurance time was defined in this study as the maximum length of time during which an individual was capable of lifting a given load at a given frequency continuously. The upper limit of endurance time was set to 8 h. Eleven male subjects participated in this study, and the lifting technique utilized with the straight back-bent knees method. The results showed that endurance time was significantly reduced with an increase in frequency or load of lift. The lightest frequency-load combination (4 times/min; 5 kg) was maintained by most of the subjects for 8 h. Conversely, the average endurance time for the heaviest frequency-load combination (10 times/min; 20 kg) was about 27 minutes.

Adult↗
PubMed1989

An endurance training programme for frequent manual carrying tasks.

This study was conducted with the aim of testing whether the endurance time of new employees engaged in frequent industrial carrying tasks can be significantly increased through a short training programme (2.5 weeks). Endurance time was here defined as the maximum length of time during which an individual can continuously carry a 20 kg load over a 4 m distance 8 times/min. The results showed that (1) endurance time increased by almost 100% over an 8-session training programme; (2) for a fixed workload, endurance time increased without changing job demand perception; and (3) overall body fatigue may be the limiting factor in frequent carrying tasks.

Adult↗
PubMed1988

A knowledge-based system for the design of manual materials handling.

The purpose of this paper is to develop and test an expert system for the design of new and existing repetitive manual materials handling (RMMH) tasks. For new jobs, the expert system provides recommendations on the maximum acceptable weight to be handled under a variety of worker and task variables. For existing jobs, the expert system provides possible solutions to the design of RMMH tasks if the weight handled on the job is greater than the recommended one. The expert system was implemented on an IBM PCXT personal computer. Two examples on how to utilise the expert system in designing new and existing jobs are given.

Journal Article↗
PubMed1988

Physiological stresses associated with television camera operators' tasks.

This study was undertaken to evaluate the physiological stresses experienced by news media cameramen on their jobs. The tasks performed by the cameramen were simulated, based on the results of monitoring the field performance of these camera operators for a two-week period. Four male professional camera operators volunteered to participate in this study. Heart rate and oxygen consumption were selected to measure the physiological stresses associated with the camera operator's jobs. The results clearly show that jobs performed by the news media camera operators working for small television stations include very demanding physical tasks. The camera operator's job could be classified, based on physiological costs, as heavy work. A detailed discussion of the results and their implications in the process of camera operator's job redesign is given.

Journal Article↗
PubMed1988

Physiological guidelines for the design of manual lifting and lowering tasks: the state of the art.

The goal of many researchers and practitioners of occupational health and safety has been to design manual materials handling (MMH) tasks so as to reduce the frequency and severity of overexertion injuries usually associated with these types of tasks. Physiological limits with respect to the manual lifting and lowering aspects of MMH have been reviewed and evaluated. The information provided by different researchers has been presented in a concise manner that is easily accessed by designers and practitioners of MMH. Recommendations for future research in determining physiological limits of individuals engaged in manual lifting and lowering tasks and other aspects of MMH activities have been provided.

Energy Metabolism↗
PubMed1987

Determination of lifting abilities: a comparative study of four techniques.

The main objective of this study was to test the differences among four techniques for the determination of lifting abilities. This study introduced a new submaximal isometric strength testing technique. The proposed test was based on the concept of acceptable maximum effort (AME) which is the level of static exertion the individual is willing to perform voluntarily and comfortably without over-exertion (as opposed to the maximum ability of performance). Twelve male and five female subjects underwent the protocol of the four strength testing techniques investigated: isometric maximum voluntary contraction (MVC); maximum acceptable weight (MAW); maximum dynamic lifting (MDL); and acceptable maximum effort (AME). The results showed that MAW recorded the lowest values followed by AME, then MDL, then MVC. The correlation between AME and MAW was higher than that found between MVC and MAW. Also, it was found that AME is a reproducible measure of muscular functional abilities. On the average, the coefficient of variation was less than 15% for data for both males and females. The implications of these results in determining lifting abilities are discussed.

Adult↗
PubMed1986

Physiologic responses to static, dynamic and combined work.

The main objective of the present study was to determine the effects on cardiovascular stress of tasks that have varying degrees of static and dynamic components (weight holding, manual lifting and stepping). Heart rate, oxygen consumption and blood pressure were used as indices of cardiovascular stress. The results showed that oxygen consumption and heart rate responses to manual lifting are significantly lower than those of stepping and higher than those of weight holding. A low frequency lifting task evoked significantly lower systolic blood pressure than a high frequency lifting task. This study supported the idea that a physiologic fatigue criterion (PFC) based on stepping should not be applied directly to tasks such as manual lifting. In addition, a PFC for manual lifting should not be based only on oxygen consumption or heart rate; it also should incorporate systolic blood pressure as one of the monitored stress factors in setting lifting standards.

Adult↗
PubMed1985

Physiological limits in lifting.

Two different experiments were conducted to study the effects of frequency, height and load of lift on computed maximal oxygen uptake and to compare the data obtained to a standard bicycle ergometer. A progressive submaximal technique was used to predict maximal oxygen uptake. The results of the present study revealed that across all heights, an increase in either the frequency of lift or load of lift was accompanied by an increase in computed maximal oxygen uptake; however, all maximal oxygen uptake values reported showed a tendency to level off beyond the frequency of five lifts/min. The results also showed that combined arm and leg lifting recorded the highest maximal oxygen uptake followed by leg lifting then arm lifting, respectively. Maximal oxygen uptake values obtained for lifting tasks were much lower than those obtained for a bicycle ergometer. It is therefore recommended that limits for continuous work for a lifting task be based on the attainable maximal oxygen uptake for that particular task and not on a maximal oxygen uptake obtained from another task such as a bicycle ergometer test.

Adult↗