Selected physiological and perceptual responses of batsmen during a simulated one day international century : impact on performance
- Authors: Pote, Lee
- Date: 2013 , 2013-04-02
- Subjects: Cricket -- Batting , Sports -- Physiological aspects , Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5097 , http://hdl.handle.net/10962/d1001650
- Description: Background: Very few studies have examined the demands of prolonged batting on physical, psychophysical and performance responses. Objective: The purpose of this study was therefore to determine the physiological and perceptual responses of batsmen scoring a simulated One Day International century. Furthermore, the impact that these responses had on batting performance were also measured. Methods: Seventeen male cricketers currently playing for Rhodes University or the country districts side, performed a simulated bating innings (BATEX©), typical of scoring a One Day international century. The BATEX© protocol consisted of six, five over stages (21 minutes each), with each stage matched to a specific phase of play where batsmen were encouraged to bat with the mindset of that phase. During stages one, three and five players ran at a “self-selected cruise pace” whereas during stages two, four and six players were required to run at maximum speed. At set intervals, selected physiological, perceptual and performance measures were recorded. Results: Most physiological responses increased and decreased accordingly with the low and high intensity stages with the exception of respiratory exchange ratio and core temperature responses. Mean physiological responses however, showed a progressive rise over time. Central ratings of perceived exertion increased as a function of intensity and duration. Sprint times got slower as the protocol progressed, while accuracy (impact accuracy) improved significantly (p<0.05) after stage one and then stabilised for the remainder of the protocol. Conclusion: The simulated batting protocol significantly impacted the physiological and perceptual responses over time. This was due to both the intensity and the duration of the work-bout. Furthermore, the increased physiological load placed on the batsmen significantly impacted the physical performance of the batsmen. An increase in sprint times (players getting slower) towards the end of the protocol may indicate the presence of physical fatigue. This physical fatigue did not however seem to impact the batsmen cognitively as accuracy improved after the first stage and then remained constant over time.
- Full Text:
- Date Issued: 2013
- Authors: Pote, Lee
- Date: 2013 , 2013-04-02
- Subjects: Cricket -- Batting , Sports -- Physiological aspects , Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5097 , http://hdl.handle.net/10962/d1001650
- Description: Background: Very few studies have examined the demands of prolonged batting on physical, psychophysical and performance responses. Objective: The purpose of this study was therefore to determine the physiological and perceptual responses of batsmen scoring a simulated One Day International century. Furthermore, the impact that these responses had on batting performance were also measured. Methods: Seventeen male cricketers currently playing for Rhodes University or the country districts side, performed a simulated bating innings (BATEX©), typical of scoring a One Day international century. The BATEX© protocol consisted of six, five over stages (21 minutes each), with each stage matched to a specific phase of play where batsmen were encouraged to bat with the mindset of that phase. During stages one, three and five players ran at a “self-selected cruise pace” whereas during stages two, four and six players were required to run at maximum speed. At set intervals, selected physiological, perceptual and performance measures were recorded. Results: Most physiological responses increased and decreased accordingly with the low and high intensity stages with the exception of respiratory exchange ratio and core temperature responses. Mean physiological responses however, showed a progressive rise over time. Central ratings of perceived exertion increased as a function of intensity and duration. Sprint times got slower as the protocol progressed, while accuracy (impact accuracy) improved significantly (p<0.05) after stage one and then stabilised for the remainder of the protocol. Conclusion: The simulated batting protocol significantly impacted the physiological and perceptual responses over time. This was due to both the intensity and the duration of the work-bout. Furthermore, the increased physiological load placed on the batsmen significantly impacted the physical performance of the batsmen. An increase in sprint times (players getting slower) towards the end of the protocol may indicate the presence of physical fatigue. This physical fatigue did not however seem to impact the batsmen cognitively as accuracy improved after the first stage and then remained constant over time.
- Full Text:
- Date Issued: 2013
An investigation into control mechanisms of driving performance : resource depletion and effort-regulation
- Authors: Louw, Tyron Linton
- Date: 2013
- Subjects: Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5101 , http://hdl.handle.net/10962/d1001842 , Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue
- Description: Driver fatigue is a complex phenomenon that has a range of causal factors including sleeprelated and task-related factors. These manifest as different safety and performance outcomes. Extensive research has been applied to linking these factors to performance impairment. However, little research focuses on the mechanisms by which this link exists. This research project therefore focuses on the processes underlying how driving performance is controlled and maintained during the development on non-sleep-related driver fatigue. The main aim was to establish whether progressive impairment of driving control over a prolonged drive could be attributed to a depletion of attentional resources, as proposed by Resource Theory, or to a withdrawal of effort, as proposed by Effort-Regulation Theory. As a multicomponent skill, driving requires perception, cognition and motor output. The secondary aim of this research was therefore to assess whether a prolonged drive impairs stage-specific information processing. Participants (n=24) in three experimental groups performed a 90-minute simulated drive wherein they were expected to keep the bonnet of a car on a lane (tracking task). The three groups differed in terms of lane width: small, medium and large, corresponding to low, medium, and high task-demand, respectively. To assess the impacts of this task on stagespecific information processing, participants performed a set of resource specific tests before and after the prolonged drive. Each task had two difficulty variations to ensure that performance decrement was due not only to the task-characteristic, but specifically to resource depletion. The tests probing information processing were: a modified Fitts' tapping task for motor programming, a digit recall task for perception, and an object recognition reading task for cognition. Performance was measured as lateral deviation of the car. Physiological measures included heart rate frequency (HR) and various time- and frequencydomain heart rate variability (HRV) parameters, eye blink frequency and duration. The Borg CR-10 scale was used to evaluate subjective effort and fatigue during the task. Driving control declined over time and was supplemented by HR, HRV, blink frequency and duration, indicating an increase in parasympathetic activity (or a reduction in arousal). An increase in blink frequency was considered as a sign of withdrawal of attentional resources over time. Driving control declined to a greater extent in the large road width group and reflected a lower parasympathetic activity, whereas the inverse was observed for the small road width group. Resource tests reveal a non-specific impairment of information processing following the prolonged drive. However, this was accompanied by an increase in parasympathetic activity. Overall, results indicate that Effort-Regulation Theory better accounts for the impairment of driving control in prolonged driving than does Resource Theory. This suggests that the impact of fatigue is guided more by task goals and intrinsic motivation than by the manner in which the fatigue state developed. Moreover, performance impairment by effort-regulation is dependant more on time on task than on task-demand
- Full Text:
- Date Issued: 2013
- Authors: Louw, Tyron Linton
- Date: 2013
- Subjects: Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5101 , http://hdl.handle.net/10962/d1001842 , Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue
- Description: Driver fatigue is a complex phenomenon that has a range of causal factors including sleeprelated and task-related factors. These manifest as different safety and performance outcomes. Extensive research has been applied to linking these factors to performance impairment. However, little research focuses on the mechanisms by which this link exists. This research project therefore focuses on the processes underlying how driving performance is controlled and maintained during the development on non-sleep-related driver fatigue. The main aim was to establish whether progressive impairment of driving control over a prolonged drive could be attributed to a depletion of attentional resources, as proposed by Resource Theory, or to a withdrawal of effort, as proposed by Effort-Regulation Theory. As a multicomponent skill, driving requires perception, cognition and motor output. The secondary aim of this research was therefore to assess whether a prolonged drive impairs stage-specific information processing. Participants (n=24) in three experimental groups performed a 90-minute simulated drive wherein they were expected to keep the bonnet of a car on a lane (tracking task). The three groups differed in terms of lane width: small, medium and large, corresponding to low, medium, and high task-demand, respectively. To assess the impacts of this task on stagespecific information processing, participants performed a set of resource specific tests before and after the prolonged drive. Each task had two difficulty variations to ensure that performance decrement was due not only to the task-characteristic, but specifically to resource depletion. The tests probing information processing were: a modified Fitts' tapping task for motor programming, a digit recall task for perception, and an object recognition reading task for cognition. Performance was measured as lateral deviation of the car. Physiological measures included heart rate frequency (HR) and various time- and frequencydomain heart rate variability (HRV) parameters, eye blink frequency and duration. The Borg CR-10 scale was used to evaluate subjective effort and fatigue during the task. Driving control declined over time and was supplemented by HR, HRV, blink frequency and duration, indicating an increase in parasympathetic activity (or a reduction in arousal). An increase in blink frequency was considered as a sign of withdrawal of attentional resources over time. Driving control declined to a greater extent in the large road width group and reflected a lower parasympathetic activity, whereas the inverse was observed for the small road width group. Resource tests reveal a non-specific impairment of information processing following the prolonged drive. However, this was accompanied by an increase in parasympathetic activity. Overall, results indicate that Effort-Regulation Theory better accounts for the impairment of driving control in prolonged driving than does Resource Theory. This suggests that the impact of fatigue is guided more by task goals and intrinsic motivation than by the manner in which the fatigue state developed. Moreover, performance impairment by effort-regulation is dependant more on time on task than on task-demand
- Full Text:
- Date Issued: 2013
The impact of low to moderate alcohol consumption on different types of human performance
- Authors: Goble, David
- Date: 2013
- Subjects: Alcohol -- Physiological effect Temperance Human information processing -- Effect of drugs on Visual perception -- Effect of drugs on Cognition -- Effect of drugs on Caffeine -- Physiological effect
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5136 , http://hdl.handle.net/10962/d1006042
- Description: Despite extensive research into the effects of alcohol consumption, there is no clear understanding into the mechanisms underlying human information processing impairment. The acute consumption of alcohol was investigated to determine the implications for human information processing capabilities, and to identify the extent to which these implications were stage-specific. Further aims included the investigation and quantification of caffeine-induced antagonism of alcohol impairment. Moreover, the aforementioned relationships were investigated in morning versus evening conditions. A test battery of six resource-specific tasks was utilised to measure visual perceptual, cognitive and sensory-motor performance, fashioned to return both simple and complex measures of each task. The tasks implemented were: visual perceptual performance (accommodation, visual detection, visual pattern recognition); cognition (memory recall- digit span); and motor output (modified Fitts‟ and a driving simulated line-tracking). Performance measures were recorded by the respective computer based tasks. Physiological variables measured included heart rate frequency, heart rate variability (RMSSD, High and Low Frequency Power) and body temperature. Saccade speed, saccade amplitude, pupil size and fixation duration were the oculomotor parameters measured. Three groups of participants (alcohol, caffeine+alcohol and control) n=36 were studied, split evenly between sexes in a mixed repeated/non-repeated measures design. The control group performed all test batteries under no influence. The alcohol group performed test batteries one and two sober, and three and four under the influence of a 0.4 g/kg dose of alcohol. Group caffeine+alcohol conducted test battery one sober, two under the effect of caffeine only (4 mg/kg), and three and four under the influence of both caffeine and alcohol (0.4 g/kg). The third test battery demonstrated the effects of alcohol during the inclining phase of the blood alcohol curve, and the fourth represented the declining phase. Morning experimentation occurred between 10:00 - 12: 45 and 10:30 -13:15 with evening experimentation between 19:00 - 21:30 and 19:30 - 22:00. Acute alcohol consumption at a dose of approximately 0.4 g/kg body weight effected an average peak breath alcohol concentration of 0.062 % and 0.059 % for the alcohol and caffeine+alcohol groups respectively. Task-related visual perceptual performance demonstrated significant decrements for simple reaction time, choice reaction time and error rate. Cognitive performance demonstrated no significant performance decrements, while motor performance indicated significant decrements in target accuracy only. Physiological parameters in response to alcohol consumption showed significantly decreased heart rate variability (RMSSD) in the modified Fitts‟ task only. A significant decrease in saccade amplitude in the memory task was the only change in oculomotor parameters. Prior caffeine consumption demonstrated limited antagonism to task-related alcohol impairment, significantly improving performance only in reduced error rate while reading. Caffeine consumption showed stimulating effects on physiological parameters, significantly increasing heart rate and heart rate variability when compared to alcohol alone. The design of the tasks allows for comparison between complex and simple task performance, indicating resource utilisation and depletion. Complex tasks demonstrated higher resource utilisation, however with no statistical performance differences to simple tasks. Physiological parameters showed greater change in response to alcohol consumption, than did the performance measures. Alcohol consumption imposed significant changes in physiological and oculomotor parameters for cognitive tasks only, significantly increasing heart rate frequency and decreasing heart rate variability, skin temperature and saccade amplitude. Caffeine consumption showed no antagonism of alcohol-induced performance measures. Physiological measures showed that caffeine consumption imposed stimulating effects in only the neural reflex and memory tasks, significantly increasing heart rate frequency and heart rate variability. Prior caffeine consumption significantly decreased fixation duration in the memory task only. The time of day at which alcohol was consumed demonstrated significant performance and physiological implications. Results indicated that morning consumption of alcohol imposes greater decrements in performance and larger fluctuations in physiological parameters than the decrements in evening experimental sessions. It can be concluded that alcohol consumption at a dose of 0.4 g/kg affects all stages in the information processing chain. Task performance indicates that alcohol has a greater severity on the early stages of information processing. Conversely, under the influence of alcohol an increased task complexity induces greater effects on central stage information processing. In addition, caffeine consumption at a dose of 4 mg/kg prior to alcohol does not antagonise the alcohol-induced performance decrements.
- Full Text:
- Date Issued: 2013
- Authors: Goble, David
- Date: 2013
- Subjects: Alcohol -- Physiological effect Temperance Human information processing -- Effect of drugs on Visual perception -- Effect of drugs on Cognition -- Effect of drugs on Caffeine -- Physiological effect
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5136 , http://hdl.handle.net/10962/d1006042
- Description: Despite extensive research into the effects of alcohol consumption, there is no clear understanding into the mechanisms underlying human information processing impairment. The acute consumption of alcohol was investigated to determine the implications for human information processing capabilities, and to identify the extent to which these implications were stage-specific. Further aims included the investigation and quantification of caffeine-induced antagonism of alcohol impairment. Moreover, the aforementioned relationships were investigated in morning versus evening conditions. A test battery of six resource-specific tasks was utilised to measure visual perceptual, cognitive and sensory-motor performance, fashioned to return both simple and complex measures of each task. The tasks implemented were: visual perceptual performance (accommodation, visual detection, visual pattern recognition); cognition (memory recall- digit span); and motor output (modified Fitts‟ and a driving simulated line-tracking). Performance measures were recorded by the respective computer based tasks. Physiological variables measured included heart rate frequency, heart rate variability (RMSSD, High and Low Frequency Power) and body temperature. Saccade speed, saccade amplitude, pupil size and fixation duration were the oculomotor parameters measured. Three groups of participants (alcohol, caffeine+alcohol and control) n=36 were studied, split evenly between sexes in a mixed repeated/non-repeated measures design. The control group performed all test batteries under no influence. The alcohol group performed test batteries one and two sober, and three and four under the influence of a 0.4 g/kg dose of alcohol. Group caffeine+alcohol conducted test battery one sober, two under the effect of caffeine only (4 mg/kg), and three and four under the influence of both caffeine and alcohol (0.4 g/kg). The third test battery demonstrated the effects of alcohol during the inclining phase of the blood alcohol curve, and the fourth represented the declining phase. Morning experimentation occurred between 10:00 - 12: 45 and 10:30 -13:15 with evening experimentation between 19:00 - 21:30 and 19:30 - 22:00. Acute alcohol consumption at a dose of approximately 0.4 g/kg body weight effected an average peak breath alcohol concentration of 0.062 % and 0.059 % for the alcohol and caffeine+alcohol groups respectively. Task-related visual perceptual performance demonstrated significant decrements for simple reaction time, choice reaction time and error rate. Cognitive performance demonstrated no significant performance decrements, while motor performance indicated significant decrements in target accuracy only. Physiological parameters in response to alcohol consumption showed significantly decreased heart rate variability (RMSSD) in the modified Fitts‟ task only. A significant decrease in saccade amplitude in the memory task was the only change in oculomotor parameters. Prior caffeine consumption demonstrated limited antagonism to task-related alcohol impairment, significantly improving performance only in reduced error rate while reading. Caffeine consumption showed stimulating effects on physiological parameters, significantly increasing heart rate and heart rate variability when compared to alcohol alone. The design of the tasks allows for comparison between complex and simple task performance, indicating resource utilisation and depletion. Complex tasks demonstrated higher resource utilisation, however with no statistical performance differences to simple tasks. Physiological parameters showed greater change in response to alcohol consumption, than did the performance measures. Alcohol consumption imposed significant changes in physiological and oculomotor parameters for cognitive tasks only, significantly increasing heart rate frequency and decreasing heart rate variability, skin temperature and saccade amplitude. Caffeine consumption showed no antagonism of alcohol-induced performance measures. Physiological measures showed that caffeine consumption imposed stimulating effects in only the neural reflex and memory tasks, significantly increasing heart rate frequency and heart rate variability. Prior caffeine consumption significantly decreased fixation duration in the memory task only. The time of day at which alcohol was consumed demonstrated significant performance and physiological implications. Results indicated that morning consumption of alcohol imposes greater decrements in performance and larger fluctuations in physiological parameters than the decrements in evening experimental sessions. It can be concluded that alcohol consumption at a dose of 0.4 g/kg affects all stages in the information processing chain. Task performance indicates that alcohol has a greater severity on the early stages of information processing. Conversely, under the influence of alcohol an increased task complexity induces greater effects on central stage information processing. In addition, caffeine consumption at a dose of 4 mg/kg prior to alcohol does not antagonise the alcohol-induced performance decrements.
- Full Text:
- Date Issued: 2013
South African anthropometric dimensions for the design of an ergonomic office chair
- Authors: Korte, Janice
- Date: 2013 , 2013-09-05
- Subjects: Design -- Human factors , Office chairs , Chair design , Human engineering , Sitting position
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5137 , http://hdl.handle.net/10962/d1006046 , Design -- Human factors , Office chairs , Chair design , Human engineering , Sitting position
- Description: Office chairs are becoming a modern status symbol in the workplace. Many individuals are seated on office chairs for most of the working day. As a result of using poorly designed chairs injury and discomfort are frequently experienced, most particularly lower back pain. Correct design of chairs is imperative, and must be user-centered. The aim of this investigation has been to gather anthropometric dimensions characteristic of the South African population, as this information has not been widely assimilated to date. Once collated, this information could be used in the design of an ergonomically correct office chair, suitable for the unique characteristics of the South African working population. Anthropometric dimensions were collected from 683 South Africans (comprising 448 South African females and 235 South African males) from pre-selected companies in major centres in South Africa (Johannesburg, Pietermaritzburg, Durban, East London, Grahamstown, Port Elizabeth and Cape Town). Measurements included participants’ personal information (age, sex, home language and ethnic group), basic anthropometric measures (stature, shoulder height, mass, and waist and hip circumference) as well as specific measures of fit of the individual to the specially designed, adjustable chair. Of the 448 females, 317 were Black females, 77 were White females, 35 were Coloured females and 19 were Indian/Asian females. Of the 235 males, 112 were Black males, 79 were White males, 26 were Coloured males and 18 were Indian/Asian males. Office chair dimensions for each ethnic group were represented and differences were noted. A comparison between a current office chair’s dimensions and the South African sample office chair’s dimensions indicated modifications that would need to be constructed to suit the South African sample. The conventional office chair is still the most widely accepted office chair due to its stability and support structures that maintain the correct sitting posture of the user. An ergonomic office chair needs to incorporate anthropometric dimensions worldwide.
- Full Text:
- Date Issued: 2013
- Authors: Korte, Janice
- Date: 2013 , 2013-09-05
- Subjects: Design -- Human factors , Office chairs , Chair design , Human engineering , Sitting position
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5137 , http://hdl.handle.net/10962/d1006046 , Design -- Human factors , Office chairs , Chair design , Human engineering , Sitting position
- Description: Office chairs are becoming a modern status symbol in the workplace. Many individuals are seated on office chairs for most of the working day. As a result of using poorly designed chairs injury and discomfort are frequently experienced, most particularly lower back pain. Correct design of chairs is imperative, and must be user-centered. The aim of this investigation has been to gather anthropometric dimensions characteristic of the South African population, as this information has not been widely assimilated to date. Once collated, this information could be used in the design of an ergonomically correct office chair, suitable for the unique characteristics of the South African working population. Anthropometric dimensions were collected from 683 South Africans (comprising 448 South African females and 235 South African males) from pre-selected companies in major centres in South Africa (Johannesburg, Pietermaritzburg, Durban, East London, Grahamstown, Port Elizabeth and Cape Town). Measurements included participants’ personal information (age, sex, home language and ethnic group), basic anthropometric measures (stature, shoulder height, mass, and waist and hip circumference) as well as specific measures of fit of the individual to the specially designed, adjustable chair. Of the 448 females, 317 were Black females, 77 were White females, 35 were Coloured females and 19 were Indian/Asian females. Of the 235 males, 112 were Black males, 79 were White males, 26 were Coloured males and 18 were Indian/Asian males. Office chair dimensions for each ethnic group were represented and differences were noted. A comparison between a current office chair’s dimensions and the South African sample office chair’s dimensions indicated modifications that would need to be constructed to suit the South African sample. The conventional office chair is still the most widely accepted office chair due to its stability and support structures that maintain the correct sitting posture of the user. An ergonomic office chair needs to incorporate anthropometric dimensions worldwide.
- Full Text:
- Date Issued: 2013
The factors affecting self-regulation through the analysis of physiological, psychological and behavioural measures during task-switching
- Authors: Chaplin, Caley
- Date: 2013 , 2013-07-16
- Subjects: Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5135 , http://hdl.handle.net/10962/d1006027 , Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Description: Individuals are required to manage multiple tasks which require strategic allocation of time and effort to ensure goals are reached efficiently. By providing the worker with autonomy over their work, performance and worker well-being have improved. This increased control allows individuals to organize work according to the needs of the body, which prevents fatigue leading to improved productivity. When given the option, humans tend to switch between tasks frequently. This behaviour can be used to determine the change in self-regulation strategies. An understanding of human task-switching behaviour is important for the design of job rotation systems. However, there is a lack of evidence explaining the factors motivating the need to switch between tasks. This study aims to use physiological, subjective and behavioural measures to explain the factors influencing selfregulation through the act of task-switching. Three primary hypotheses were developed to explain the factors underlying taskswitching behaviour. It was hypothesized that the degree of boredom experienced, the effort required to perform the task and the resource usage induced by the task are factors responsible in deciding task switching behaviour. Participants (17 males and 17 females) switched freely between five different information-processing tasks for the 45 minutes. Participants were allowed to switch back and forth between tasks and did not have to conduct all five tasks. The following measures were recorded during the experiment: subjective measures of boredom, mental effort, task frustration and perceived performance of the tasks; energy consumption and physiological measures of effort (HR, HRV and body temperature) and behavioural measures, including duration and frequency of task. Perceived boredom was found to differ among the tasks and before and after the experiment. The average boredom rating at each task transition for all tasks exceeded a score of 2.5 out of a possible 4. There were no significant changes in physiological measures between the beginning and end of the task trials. However, changes in physiological measures showed a decrease in effort investment following task transition. Heart rate variability was lower for externally-paced tasks than for self-paced tasks, despite the differences in cognitive demands. The most frequent task-switch combination occurred between tasks of high and low cognitive demand. The least frequent task-switching combination occurred between tasks of similar characteristics, which produced no differences in physiological responses. Task-switching behaviour was influenced by the degree of boredom, and therefore more time was spent on less monotonous tasks. The level of physiological effort required for the task affected task-switching behaviour. Task switches were made before any changes in effort took place in an attempt to maintain task efficiency. It appears plausible that a task switch was made to reduce effort investment and activation levels. The type of information processing resources used by different tasks affected the task-switching combinations. Individuals tended to switch between tasks of differing resources so that those in limited supply were able to replenish. Therefore the findings from this study can potentially be used to improve the design of job rotation systems. Such improvements may enhance productivity and worker well-being by inhibiting the onset of down regulation and fatigue processes. This study showed that autonomy is necessary for individuals to regulate behaviour to suit human needs. , Microsoft� Office Word 2007 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Chaplin, Caley
- Date: 2013 , 2013-07-16
- Subjects: Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5135 , http://hdl.handle.net/10962/d1006027 , Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Description: Individuals are required to manage multiple tasks which require strategic allocation of time and effort to ensure goals are reached efficiently. By providing the worker with autonomy over their work, performance and worker well-being have improved. This increased control allows individuals to organize work according to the needs of the body, which prevents fatigue leading to improved productivity. When given the option, humans tend to switch between tasks frequently. This behaviour can be used to determine the change in self-regulation strategies. An understanding of human task-switching behaviour is important for the design of job rotation systems. However, there is a lack of evidence explaining the factors motivating the need to switch between tasks. This study aims to use physiological, subjective and behavioural measures to explain the factors influencing selfregulation through the act of task-switching. Three primary hypotheses were developed to explain the factors underlying taskswitching behaviour. It was hypothesized that the degree of boredom experienced, the effort required to perform the task and the resource usage induced by the task are factors responsible in deciding task switching behaviour. Participants (17 males and 17 females) switched freely between five different information-processing tasks for the 45 minutes. Participants were allowed to switch back and forth between tasks and did not have to conduct all five tasks. The following measures were recorded during the experiment: subjective measures of boredom, mental effort, task frustration and perceived performance of the tasks; energy consumption and physiological measures of effort (HR, HRV and body temperature) and behavioural measures, including duration and frequency of task. Perceived boredom was found to differ among the tasks and before and after the experiment. The average boredom rating at each task transition for all tasks exceeded a score of 2.5 out of a possible 4. There were no significant changes in physiological measures between the beginning and end of the task trials. However, changes in physiological measures showed a decrease in effort investment following task transition. Heart rate variability was lower for externally-paced tasks than for self-paced tasks, despite the differences in cognitive demands. The most frequent task-switch combination occurred between tasks of high and low cognitive demand. The least frequent task-switching combination occurred between tasks of similar characteristics, which produced no differences in physiological responses. Task-switching behaviour was influenced by the degree of boredom, and therefore more time was spent on less monotonous tasks. The level of physiological effort required for the task affected task-switching behaviour. Task switches were made before any changes in effort took place in an attempt to maintain task efficiency. It appears plausible that a task switch was made to reduce effort investment and activation levels. The type of information processing resources used by different tasks affected the task-switching combinations. Individuals tended to switch between tasks of differing resources so that those in limited supply were able to replenish. Therefore the findings from this study can potentially be used to improve the design of job rotation systems. Such improvements may enhance productivity and worker well-being by inhibiting the onset of down regulation and fatigue processes. This study showed that autonomy is necessary for individuals to regulate behaviour to suit human needs. , Microsoft� Office Word 2007 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
An empirical investigation into task aversion
- Authors: Sunshine, Megan
- Date: 2013 , 2013-07-25
- Subjects: Work aversion , Mental fatigue , Labor productivity , Employees -- Workload , Industrial hygiene
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5138 , http://hdl.handle.net/10962/d1006085 , Work aversion , Mental fatigue , Labor productivity , Employees -- Workload , Industrial hygiene
- Description: Aversion is a complex phenomenon that arises over time through performance of cognitively demanding tasks and has been associated with the mechanisms of mental fatigue and compensatory control. However, little is known about this sensation to dissociate from the task at hand and the causation thereof. It is apparent that aversion is a negative state for the operator and could result in decreased performance and productivity. Through identification of factors that contribute to aversion when performing cognitively demanding tasks, recommendations to reduce design deficits may be employed to promote worker wellbeing and further advance performance and productivity. The current study examined possible factors that may influence aversion experienced through execution of cognitive tasks. A subsequent aim of this study was to assess a possible cause of aversion. The cause of aversion was hypothesized to be related to efficiency, namely the perception of efficiency when performing tasks and actual efficiency calculated through performance of tasks in relation to the expenditure of effort. Four investigations were undertaken with a non-repeated design between investigations and a repeated design within investigations. The first investigation was an analysis of the effect that stimulus cycling had on the aversion experienced. This consisted of a proof reading task with two conditions varying in the repetitiveness of the text, therefore, allowing an analysis as to how aversion is altered by the provision of a new stimulus to the participants. Investigation two investigated the effect that task difficulty imposed on aversion experienced. This comprised of two conditions with varied difficulty that were implemented through a driving simulator tracking task with difficulty altered by the width of the driving lane. The effect of performance feedback on the aversion experienced towards a task was the focus of the third investigation. The effect on aversion experienced was assessed through a driving simulator tracking task with a condition providing feedback of performance to participants and a condition with no knowledge of performance. The final experiment evaluated the effect of task alternations on aversion. This experiment was conducted through alternations between a driving simulator tracking task and a choice reaction task. The choice reaction tasks required participants to identify critical and non-critical stimulus. Four conditions were required for this experiment and were made up of two conditions where there was provision of alternation that varied in frequencies between the two tasks (medium alternation condition and fast alternation condition) and two conditions where no alternations were instated (driving simulator task condition and choice reaction task condition). Separations between all testing conditions were three or more days apart with sixty participants distributed between the investigations. Test duration of each condition was 30 minutes. Subjective data was recorded throughout investigations for all conditions in the form of aversion, subjectively perceived efficiency and rate of perceived exertion. Objective data was collected in the form of physiological responses and performance of tasks for the analysis of objective efficiency. For factors influencing aversion analysis, no differences in aversion experienced were found for the task difficulty and performance feedback investigations. Aversion was found to be less for the changes imposed through the task cycles and task alternation investigations. This concludes that aversion is aggravated through monotonous tasks and by a change of the stimulus or the structure of the cognitive tasks provided to operators; aversion can be alleviated. The results for the cause of aversion analysis found no difference in objective efficiency over time, with a subsequent decrease in perceived efficiency associated with the increasing aversion. Inference from these findings suggest that aversion cannot be attributed to objective inefficiency of task performance, however it can further be assumed that perception of actual efficiency is inaccurate. Perception of efficiency however had a large influence on the sensation of aversion. Aversion is seen to be more of a product of time on task, however whether this is mechanism of fatigue or compensatory control is still to be determined.
- Full Text:
- Date Issued: 2013
- Authors: Sunshine, Megan
- Date: 2013 , 2013-07-25
- Subjects: Work aversion , Mental fatigue , Labor productivity , Employees -- Workload , Industrial hygiene
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5138 , http://hdl.handle.net/10962/d1006085 , Work aversion , Mental fatigue , Labor productivity , Employees -- Workload , Industrial hygiene
- Description: Aversion is a complex phenomenon that arises over time through performance of cognitively demanding tasks and has been associated with the mechanisms of mental fatigue and compensatory control. However, little is known about this sensation to dissociate from the task at hand and the causation thereof. It is apparent that aversion is a negative state for the operator and could result in decreased performance and productivity. Through identification of factors that contribute to aversion when performing cognitively demanding tasks, recommendations to reduce design deficits may be employed to promote worker wellbeing and further advance performance and productivity. The current study examined possible factors that may influence aversion experienced through execution of cognitive tasks. A subsequent aim of this study was to assess a possible cause of aversion. The cause of aversion was hypothesized to be related to efficiency, namely the perception of efficiency when performing tasks and actual efficiency calculated through performance of tasks in relation to the expenditure of effort. Four investigations were undertaken with a non-repeated design between investigations and a repeated design within investigations. The first investigation was an analysis of the effect that stimulus cycling had on the aversion experienced. This consisted of a proof reading task with two conditions varying in the repetitiveness of the text, therefore, allowing an analysis as to how aversion is altered by the provision of a new stimulus to the participants. Investigation two investigated the effect that task difficulty imposed on aversion experienced. This comprised of two conditions with varied difficulty that were implemented through a driving simulator tracking task with difficulty altered by the width of the driving lane. The effect of performance feedback on the aversion experienced towards a task was the focus of the third investigation. The effect on aversion experienced was assessed through a driving simulator tracking task with a condition providing feedback of performance to participants and a condition with no knowledge of performance. The final experiment evaluated the effect of task alternations on aversion. This experiment was conducted through alternations between a driving simulator tracking task and a choice reaction task. The choice reaction tasks required participants to identify critical and non-critical stimulus. Four conditions were required for this experiment and were made up of two conditions where there was provision of alternation that varied in frequencies between the two tasks (medium alternation condition and fast alternation condition) and two conditions where no alternations were instated (driving simulator task condition and choice reaction task condition). Separations between all testing conditions were three or more days apart with sixty participants distributed between the investigations. Test duration of each condition was 30 minutes. Subjective data was recorded throughout investigations for all conditions in the form of aversion, subjectively perceived efficiency and rate of perceived exertion. Objective data was collected in the form of physiological responses and performance of tasks for the analysis of objective efficiency. For factors influencing aversion analysis, no differences in aversion experienced were found for the task difficulty and performance feedback investigations. Aversion was found to be less for the changes imposed through the task cycles and task alternation investigations. This concludes that aversion is aggravated through monotonous tasks and by a change of the stimulus or the structure of the cognitive tasks provided to operators; aversion can be alleviated. The results for the cause of aversion analysis found no difference in objective efficiency over time, with a subsequent decrease in perceived efficiency associated with the increasing aversion. Inference from these findings suggest that aversion cannot be attributed to objective inefficiency of task performance, however it can further be assumed that perception of actual efficiency is inaccurate. Perception of efficiency however had a large influence on the sensation of aversion. Aversion is seen to be more of a product of time on task, however whether this is mechanism of fatigue or compensatory control is still to be determined.
- Full Text:
- Date Issued: 2013
An analysis of regulatory mechanisms during sustained task execution in cognitive, motor and sensory tasks
- Tau, Sethunya Harriet Hlobisa
- Authors: Tau, Sethunya Harriet Hlobisa
- Date: 2013 , 2013-10-11
- Subjects: Work -- Physiological aspects , Work -- Psychological aspects , Fatigue , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Employees -- Workload , Performance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5140 , http://hdl.handle.net/10962/d1006806 , Work -- Physiological aspects , Work -- Psychological aspects , Fatigue , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Employees -- Workload , Performance
- Description: Fatigue is a state that, although researched for many years, is still not completely understood. Alongside this lack of a general understanding of fatigue is a lack of knowledge on the processes involved in the regulation of fatigue. The existing theories relating to regulation are focussed on mental effort regulation, suggesting that performance outcomes are co-ordinated by effort regulation that functions by making alterations to physiological processes and strategic adjustments at a cognitive level in response to cognitive demands and goals. Since fatigue is a multi-dimensional construct with psychological, physiological, and behavioural effects that respond to endogenous and exogenous variables, it follows then that fatigue assessment techniques ought to include multi-dimensional measures to acquire a holistic depiction of the fatigue symptom. This study aimed to assess whether or not a mechanism that regulated fatigue during sustained task execution could be identified and whether this mechanism resulted in regulation patterns that were distinct to a specific task. An additional aim of the study was on assessing whether the manner in which performance, psychophysical and subjective variables were modified over time followed a similar regulation pattern. The research design was aimed at inducing task-related fatigue twice on two different occasions in the same participants and evaluating the resultant changes in fatigue manifestation. This was done to assess the ability of participants to cope with fatigue as a result of previous experience. The research protocol included three tasks executed for an hour aimed at targeting and taxing the sensory, cognitive, motor resources, each task performed twice. 60 participants were recruited to participate in the current study, with 20 participants – 10 males and 10 females – randomly assigned to each of the three tasks. The cognitive resource task consisted of a memory recall task relying on working memory intended to evaluate the extent of reductions in memory and attention. The sensory resource task consisted of a reading task measuring visual scanning and perception designed to evaluate the extent of reduced vigilance. The motor resource task consisted of a modified Fitts’ stimulus response task targeted at monitoring the extent of movement timing disruption. Performance measures comprised of: response delay and the number of correctly identified digits during the cognitive resource task, the amount of correctly identified errors and reading speed during the sensory resource task, response time during the motor resource task, and responses to simple auditory reaction time tests (RTT) initiated at intervals during the task and then again at the end of each task. Physiological measures included ear temperature, eye blink frequency and duration, heart rate (HR), and heart rate variability (HRV). Subjective measures included the use of the Ratings of Perceived Exertion Category Ratio 10 scale (RPE CR 10) to measure cognitive exertion and the NASA-Task Load Index (NASA-TLX) to index mental workload. Eye blink frequency and duration, HR and HRV were sensitive to the type of task executed, showing differing response patterns both over the different tasks and over the two test sessions. The subjective measures indicated increasing RPE ratings over time in all tasks while the NASA-TLX indicated that each task elicited different workloads. Differing task performance responses were measured between the 1st test session and the 2nd test session during all tasks; while performance was found to improve during the 2nd test session for the motor and sensory tasks, it declined during the cognitive task. The findings of this research indicate that there was a regulatory mechanism for fatigue that altered the manner in which performance, psychophysical and subjective variables were modified over time, initiating a unique fatigue regulation pattern for each variable and each task. This regulation mechanism is understood to be a proactive and protective mechanism that functions through reducing a person’s ability to be vigilant, attentive, to exercise discernment, and to direct their level of responsiveness, essentially impacting how the body adapts to and copes with fatigue. The noted overall findings have industry implications; industries should consider accounting for the effects of this regulatory mechanism in their fatigue management interventions, specifically when designing job rotation and work/rest schedules because each cognitive task, having elicited a unique fatigue regulation pattern, ought to also have a different management program. , Microsoft� Office Word 2007 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Tau, Sethunya Harriet Hlobisa
- Date: 2013 , 2013-10-11
- Subjects: Work -- Physiological aspects , Work -- Psychological aspects , Fatigue , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Employees -- Workload , Performance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5140 , http://hdl.handle.net/10962/d1006806 , Work -- Physiological aspects , Work -- Psychological aspects , Fatigue , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Employees -- Workload , Performance
- Description: Fatigue is a state that, although researched for many years, is still not completely understood. Alongside this lack of a general understanding of fatigue is a lack of knowledge on the processes involved in the regulation of fatigue. The existing theories relating to regulation are focussed on mental effort regulation, suggesting that performance outcomes are co-ordinated by effort regulation that functions by making alterations to physiological processes and strategic adjustments at a cognitive level in response to cognitive demands and goals. Since fatigue is a multi-dimensional construct with psychological, physiological, and behavioural effects that respond to endogenous and exogenous variables, it follows then that fatigue assessment techniques ought to include multi-dimensional measures to acquire a holistic depiction of the fatigue symptom. This study aimed to assess whether or not a mechanism that regulated fatigue during sustained task execution could be identified and whether this mechanism resulted in regulation patterns that were distinct to a specific task. An additional aim of the study was on assessing whether the manner in which performance, psychophysical and subjective variables were modified over time followed a similar regulation pattern. The research design was aimed at inducing task-related fatigue twice on two different occasions in the same participants and evaluating the resultant changes in fatigue manifestation. This was done to assess the ability of participants to cope with fatigue as a result of previous experience. The research protocol included three tasks executed for an hour aimed at targeting and taxing the sensory, cognitive, motor resources, each task performed twice. 60 participants were recruited to participate in the current study, with 20 participants – 10 males and 10 females – randomly assigned to each of the three tasks. The cognitive resource task consisted of a memory recall task relying on working memory intended to evaluate the extent of reductions in memory and attention. The sensory resource task consisted of a reading task measuring visual scanning and perception designed to evaluate the extent of reduced vigilance. The motor resource task consisted of a modified Fitts’ stimulus response task targeted at monitoring the extent of movement timing disruption. Performance measures comprised of: response delay and the number of correctly identified digits during the cognitive resource task, the amount of correctly identified errors and reading speed during the sensory resource task, response time during the motor resource task, and responses to simple auditory reaction time tests (RTT) initiated at intervals during the task and then again at the end of each task. Physiological measures included ear temperature, eye blink frequency and duration, heart rate (HR), and heart rate variability (HRV). Subjective measures included the use of the Ratings of Perceived Exertion Category Ratio 10 scale (RPE CR 10) to measure cognitive exertion and the NASA-Task Load Index (NASA-TLX) to index mental workload. Eye blink frequency and duration, HR and HRV were sensitive to the type of task executed, showing differing response patterns both over the different tasks and over the two test sessions. The subjective measures indicated increasing RPE ratings over time in all tasks while the NASA-TLX indicated that each task elicited different workloads. Differing task performance responses were measured between the 1st test session and the 2nd test session during all tasks; while performance was found to improve during the 2nd test session for the motor and sensory tasks, it declined during the cognitive task. The findings of this research indicate that there was a regulatory mechanism for fatigue that altered the manner in which performance, psychophysical and subjective variables were modified over time, initiating a unique fatigue regulation pattern for each variable and each task. This regulation mechanism is understood to be a proactive and protective mechanism that functions through reducing a person’s ability to be vigilant, attentive, to exercise discernment, and to direct their level of responsiveness, essentially impacting how the body adapts to and copes with fatigue. The noted overall findings have industry implications; industries should consider accounting for the effects of this regulatory mechanism in their fatigue management interventions, specifically when designing job rotation and work/rest schedules because each cognitive task, having elicited a unique fatigue regulation pattern, ought to also have a different management program. , Microsoft� Office Word 2007 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The influence of soccer-specific fatigue on the risk of thigh injuries in amateur black African players
- Authors: Jones, Robert Ian
- Date: 2013
- Subjects: Soccer injuries -- South Africa -- Eastern Cape Thigh -- Wounds and injuries -- South Africa -- Eastern Cape Hamstring muscle -- Wounds and injuries -- South Africa -- Eastern Cape Black people -- Wounds and injuries -- South Africa -- Eastern Cape Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5100 , http://hdl.handle.net/10962/d1001841
- Description: Background: Epidemiological findings indicate a higher risk of muscular thigh strain injury during the latter stages of both halves of soccer match-play, with muscular fatigue highlighted as a key etiological factor in injury causation. Anthropometric, biomechanical and physiological differences present in the Black African population may elicit unique thigh injury risk profiles, different from those of European and American players. Objectives: The purpose of the current research was to investigate the impact of soccer-specific fatigue on the risk of hamstring and quadricep injury in amateur Black African soccer players, in both the dominant and non-dominant legs. Methods: Participants were required to perform a soccer matchplay simulation (SAFT⁹⁰), consisting of multidirectional and utility movements, as well as frequent acceleration and deceleration. Selected physical, physiological and psychophysical responses were collected at specific time intervals throughout fatigue protocol performance. Results: Heart rate responses were observed to increase significantly (p<0.05) in response to the start of both halves, and remain elevated (but showing no further significant increase) during the performance of the remainder of the fatigue protocol. Significant (p<0.05) changes in both concentric and eccentric isokinetic variables of the knee flexors and extensors highlight the effect of muscular fatigue on performance in soccer match-play. Eccentric hamstring peak torque was observed to decrease significantly over time (60°.s⁻ₑ=17.34%, 180°.s⁻ₑ=18.27%), with significant reductions observed during both halves. The functional H:Q ratio at 180°.s⁻ₑ indicated a significant decrease over time (10.04%), with a significant decrease indicated during the second half of the SAFT⁹⁰ protocol. The passive half time interval did not result in significant changes in isokinetic variables. Isokinetic strength, work and power indicated no significant effects of leg dominance.. ‘Central’ and ‘Local’ ratings of exertion were observed to increase significantly (p<0.05) as a function of exercise duration. Conclusion: The overall reduction in both the eccentric hamstring peak torque and the functional strength ratio was illustrated to be similar to that of other soccer-specific fatigue research. As a result, the risk of thigh strain injuries is suggested to be similar regardless of playing level and race. These time dependent changes may have implications for competitive performance and increased predisposition to hamstring strain injuries during the latter stages of both halves of match-play
- Full Text:
- Date Issued: 2013
- Authors: Jones, Robert Ian
- Date: 2013
- Subjects: Soccer injuries -- South Africa -- Eastern Cape Thigh -- Wounds and injuries -- South Africa -- Eastern Cape Hamstring muscle -- Wounds and injuries -- South Africa -- Eastern Cape Black people -- Wounds and injuries -- South Africa -- Eastern Cape Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5100 , http://hdl.handle.net/10962/d1001841
- Description: Background: Epidemiological findings indicate a higher risk of muscular thigh strain injury during the latter stages of both halves of soccer match-play, with muscular fatigue highlighted as a key etiological factor in injury causation. Anthropometric, biomechanical and physiological differences present in the Black African population may elicit unique thigh injury risk profiles, different from those of European and American players. Objectives: The purpose of the current research was to investigate the impact of soccer-specific fatigue on the risk of hamstring and quadricep injury in amateur Black African soccer players, in both the dominant and non-dominant legs. Methods: Participants were required to perform a soccer matchplay simulation (SAFT⁹⁰), consisting of multidirectional and utility movements, as well as frequent acceleration and deceleration. Selected physical, physiological and psychophysical responses were collected at specific time intervals throughout fatigue protocol performance. Results: Heart rate responses were observed to increase significantly (p<0.05) in response to the start of both halves, and remain elevated (but showing no further significant increase) during the performance of the remainder of the fatigue protocol. Significant (p<0.05) changes in both concentric and eccentric isokinetic variables of the knee flexors and extensors highlight the effect of muscular fatigue on performance in soccer match-play. Eccentric hamstring peak torque was observed to decrease significantly over time (60°.s⁻ₑ=17.34%, 180°.s⁻ₑ=18.27%), with significant reductions observed during both halves. The functional H:Q ratio at 180°.s⁻ₑ indicated a significant decrease over time (10.04%), with a significant decrease indicated during the second half of the SAFT⁹⁰ protocol. The passive half time interval did not result in significant changes in isokinetic variables. Isokinetic strength, work and power indicated no significant effects of leg dominance.. ‘Central’ and ‘Local’ ratings of exertion were observed to increase significantly (p<0.05) as a function of exercise duration. Conclusion: The overall reduction in both the eccentric hamstring peak torque and the functional strength ratio was illustrated to be similar to that of other soccer-specific fatigue research. As a result, the risk of thigh strain injuries is suggested to be similar regardless of playing level and race. These time dependent changes may have implications for competitive performance and increased predisposition to hamstring strain injuries during the latter stages of both halves of match-play
- Full Text:
- Date Issued: 2013
Changes in muscle recruitment, functional strength and ratings of perceived effort during an 8-over bowling spell: impact on performance
- Authors: Barford, Gareth Charles
- Date: 2013
- Subjects: Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5102 , http://hdl.handle.net/10962/d1003926 , Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Description: Background: The musculoskeletal demands placed on the lower limb musculature of fast bowlers over time have not received much attention. In particular, measures of muscle recruitment changes have, to the author’s knowledge, not been considered. Objective: The present study, therefore sought to establish any associations between an eight over, simulated fast bowling spell, and muscle activation patterns, power output, perceptual demands, and changes in performance. This will enable improvements in the development of training programmes. Methods: Players’ were required to attend two sessions in total. The purpose of the initial session was to collect specific demographic, anthropometric and physiological data and injury history information from each player. In addition, this first session allowed for habituation with the treadmill, the jump meter and all other equipment involved in experimentation. The second testing session involved electrode attachment sites being identified on player’s dominant leg. The areas were then shaved, wiped with an alcohol swab and left to dry, to ensure good connectivity. Pre- and post- measures of muscle activity and functional strength of the lower limbs were recorded in the Department of Human Kinetics and Ergonomics. The protocol took place at the Kingswood High Performance Centre, which is in close proximity to the initial testing site. The protocol involved players bowling eight overs (48 balls). During the protocol, accuracy, ball release speed and perceptual measures were recorded at the end of each over. After the protocol, players were driven back to the Human Kinetics and Ergonomics Department where post-testing measures were completed. The dependable variables of interest were muscle activation, functional strength of the lower limbs, ‘local’ ratings of perceived exertion (RPE), body discomfort, accuracy, and ball release speed. Results: For all muscles it was shown that, as the speed increased so did the muscle activity in players’ lower limbs. There were no significant changes in muscle activity preversus post-protocol. There was however, a general trend of decreasing muscle activity post protocol at higher testing speeds. There were significant (p<0.05) decreases in peak power following the simulated eight over bowling spell. ‘Local’ RPE displayed a significant (P<0.05) increase with each additional over and were observed to reach the ‘heavy’ category. The players’ highest discomfort area was in the lower back, with 13 players perceiving discomfort in this region following the eight over spell. The shoulder and chest were another two areas player’s indicated discomfort with eight players selecting the dominant shoulder. Seven players complained of the dominant side pectoral muscle, leading foot and dominant latissimus dorsi muscle being uncomfortable. Interestingly, the dominant pectoral showed the highest body discomfort ratings amongst players. There were no significant changes in accuracy between overs although there were large interindividual differences in accuracy points between players. The decrease in ball release speed observed during over seven was shown to be significantly (p<0.05) lower than overs one to four. Conclusion: The power output and perceived strain results of the players, appears to indicate the presence of fatigue in players. However, the results are not conclusive, as the fatigue was not shown in muscle recruitment patterns, as well as the body discomfort ratings. There was a non-significant trend observed in the lower limb muscle activation decreasing at higher speeds. Players were able to maintain accuracy. However, the significantly lower ball release speed observed during over seven showed players performance decreasing.
- Full Text:
- Date Issued: 2013
- Authors: Barford, Gareth Charles
- Date: 2013
- Subjects: Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5102 , http://hdl.handle.net/10962/d1003926 , Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Description: Background: The musculoskeletal demands placed on the lower limb musculature of fast bowlers over time have not received much attention. In particular, measures of muscle recruitment changes have, to the author’s knowledge, not been considered. Objective: The present study, therefore sought to establish any associations between an eight over, simulated fast bowling spell, and muscle activation patterns, power output, perceptual demands, and changes in performance. This will enable improvements in the development of training programmes. Methods: Players’ were required to attend two sessions in total. The purpose of the initial session was to collect specific demographic, anthropometric and physiological data and injury history information from each player. In addition, this first session allowed for habituation with the treadmill, the jump meter and all other equipment involved in experimentation. The second testing session involved electrode attachment sites being identified on player’s dominant leg. The areas were then shaved, wiped with an alcohol swab and left to dry, to ensure good connectivity. Pre- and post- measures of muscle activity and functional strength of the lower limbs were recorded in the Department of Human Kinetics and Ergonomics. The protocol took place at the Kingswood High Performance Centre, which is in close proximity to the initial testing site. The protocol involved players bowling eight overs (48 balls). During the protocol, accuracy, ball release speed and perceptual measures were recorded at the end of each over. After the protocol, players were driven back to the Human Kinetics and Ergonomics Department where post-testing measures were completed. The dependable variables of interest were muscle activation, functional strength of the lower limbs, ‘local’ ratings of perceived exertion (RPE), body discomfort, accuracy, and ball release speed. Results: For all muscles it was shown that, as the speed increased so did the muscle activity in players’ lower limbs. There were no significant changes in muscle activity preversus post-protocol. There was however, a general trend of decreasing muscle activity post protocol at higher testing speeds. There were significant (p<0.05) decreases in peak power following the simulated eight over bowling spell. ‘Local’ RPE displayed a significant (P<0.05) increase with each additional over and were observed to reach the ‘heavy’ category. The players’ highest discomfort area was in the lower back, with 13 players perceiving discomfort in this region following the eight over spell. The shoulder and chest were another two areas player’s indicated discomfort with eight players selecting the dominant shoulder. Seven players complained of the dominant side pectoral muscle, leading foot and dominant latissimus dorsi muscle being uncomfortable. Interestingly, the dominant pectoral showed the highest body discomfort ratings amongst players. There were no significant changes in accuracy between overs although there were large interindividual differences in accuracy points between players. The decrease in ball release speed observed during over seven was shown to be significantly (p<0.05) lower than overs one to four. Conclusion: The power output and perceived strain results of the players, appears to indicate the presence of fatigue in players. However, the results are not conclusive, as the fatigue was not shown in muscle recruitment patterns, as well as the body discomfort ratings. There was a non-significant trend observed in the lower limb muscle activation decreasing at higher speeds. Players were able to maintain accuracy. However, the significantly lower ball release speed observed during over seven showed players performance decreasing.
- Full Text:
- Date Issued: 2013
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