Influence of macro- versus microcooling on the physiological and psychological performance of the human operator
- Authors: Heyns, Gerhardus Johannes
- Date: 1995
- Subjects: Cold -- Physiological effect , Temperature -- Physiological effect , Body temperature -- Regulation , Heat -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5167 , http://hdl.handle.net/10962/d1016247
- Description: This study evaluated the effect of a macro- versus a microcooling system on the cognitive, psychomotor and physiological performance of human operators. Male subjects (n = 24) were acclimatized for four days and then subjected to three different environmental conditions: hot ambient (40°C; 40% RH), microcooling and macrocooling. Each environmental condition was repeated twice; once under a rest condition and once while simulating a physical workload of 40 W. Four performance tests (reasoning, eye-hand coordination, memory, reaction time) were conducted once every hour for four hours. Five physiological measurements, viz rectal temperature, skin temperature, heart rate, total sweat loss and sweat rate, were taken. A significant difference existed between the physiological responses under the hot ambient condition and both cooling conditions. For all five physiological parameters he human operator benefitted substantially whatever the cooling condition. The psychological performance results indicated a greater benefit under the cooling conditions, though various external factors may have influenced responses. User perception showed that macrocooling was perceived to be the optimal method of cooling. The results showed that there was no difference in the extent to which both rectal temperature and heart rate (for rest and work conditions) decreased over the 4-hour study period with micro- and macrocooling. In the baseline hot environment both increase. Sweat rate was lowest when resting or working in a microcooled environment and at its highest in the hot baseline environment. Mean skin temperature was lowest (for rest and work conditions) with microcooling and highest in the hot baseline environment. Reaction time and memory/attention were the same under all three environmental conditions. Eye-hand coordination was better with cooling than without, but did not differ between the two cooling conditions. Reasoning ability was poorest under the hot baseline condition and best in the macrocooled environment. User perception showed that the subjects found macrocooling highly acceptable. Microcooling was found to be uncomfortable, particularly because cold air (18 - 21°C) entered the jacket at one point which caused numbness of the skin at that point. Jackets did not always fit subjects well and the umbilical cord restricted free movement.
- Full Text:
- Date Issued: 1995
- Authors: Heyns, Gerhardus Johannes
- Date: 1995
- Subjects: Cold -- Physiological effect , Temperature -- Physiological effect , Body temperature -- Regulation , Heat -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5167 , http://hdl.handle.net/10962/d1016247
- Description: This study evaluated the effect of a macro- versus a microcooling system on the cognitive, psychomotor and physiological performance of human operators. Male subjects (n = 24) were acclimatized for four days and then subjected to three different environmental conditions: hot ambient (40°C; 40% RH), microcooling and macrocooling. Each environmental condition was repeated twice; once under a rest condition and once while simulating a physical workload of 40 W. Four performance tests (reasoning, eye-hand coordination, memory, reaction time) were conducted once every hour for four hours. Five physiological measurements, viz rectal temperature, skin temperature, heart rate, total sweat loss and sweat rate, were taken. A significant difference existed between the physiological responses under the hot ambient condition and both cooling conditions. For all five physiological parameters he human operator benefitted substantially whatever the cooling condition. The psychological performance results indicated a greater benefit under the cooling conditions, though various external factors may have influenced responses. User perception showed that macrocooling was perceived to be the optimal method of cooling. The results showed that there was no difference in the extent to which both rectal temperature and heart rate (for rest and work conditions) decreased over the 4-hour study period with micro- and macrocooling. In the baseline hot environment both increase. Sweat rate was lowest when resting or working in a microcooled environment and at its highest in the hot baseline environment. Mean skin temperature was lowest (for rest and work conditions) with microcooling and highest in the hot baseline environment. Reaction time and memory/attention were the same under all three environmental conditions. Eye-hand coordination was better with cooling than without, but did not differ between the two cooling conditions. Reasoning ability was poorest under the hot baseline condition and best in the macrocooled environment. User perception showed that the subjects found macrocooling highly acceptable. Microcooling was found to be uncomfortable, particularly because cold air (18 - 21°C) entered the jacket at one point which caused numbness of the skin at that point. Jackets did not always fit subjects well and the umbilical cord restricted free movement.
- Full Text:
- Date Issued: 1995
Physiological, perceptual and performance responses to competitive stress in individual and team sports among youth sport participants
- Authors: Swart, Kamilla
- Date: 1995
- Subjects: Sports -- Psychological aspects , Competition (Psychology) in adolescence -- Testing , Stress in adolescence -- Testing , Anxiety in adolescence -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5169 , http://hdl.handle.net/10962/d1016257
- Description: Due to limited research in the field testing of youth sport, specifically with regard to females, this project was delimited to the examination of the responses of youth participants in relation to the nature of the sport, when participating under conditions of competitive stress. It further attempted to elucidate gender related differences within these responses. Forty four male and female subjects aged 15 - 19 years volunteered to participate in this study; all pupils were First team members who competed in a variety of team and individual sports. Subjects participated in a battery of psychological, physiological and performance tests before and after competing in a practice session and during competitive league matches. The data were statistically analyzed for the various parameters under investigation. The results of the Sport Competition Anxiety Test indicated that the females, and the male team players had the highest competitive anxiety traits (CTA). The Task and Ego Orientation in Sport Questionnaire scores showed that most subjects have a general dominance of task orientation to sport. The results of the Physical Self-Perception Profile revealed that the females' poorer perception of their physical was not as substantial as their difference in CTA compared to males. Team participants, particularly the males, had a poorer self-image than individual sport counterparts. Elevated heart rate responses were observed prior to performing in a competitive ambience, with significant increases in team, rather than individual, players. The Evaluation of Task Demands revealed that team players, especially the females, perceived the match demands as significantly higher than the individual athletes. No significant differences were observed in the players' Evaluation of Perceived Strain. Neither were any significant differences observed in the players' ratings of their performance. In conclusion, although differences appear to exist between male and female responses within a competitive ambience, the magnitude of difference was far more notable between team and individual responses to competitive stress, particularly for competitive matches as opposed to practice sessions.
- Full Text:
- Date Issued: 1995
- Authors: Swart, Kamilla
- Date: 1995
- Subjects: Sports -- Psychological aspects , Competition (Psychology) in adolescence -- Testing , Stress in adolescence -- Testing , Anxiety in adolescence -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5169 , http://hdl.handle.net/10962/d1016257
- Description: Due to limited research in the field testing of youth sport, specifically with regard to females, this project was delimited to the examination of the responses of youth participants in relation to the nature of the sport, when participating under conditions of competitive stress. It further attempted to elucidate gender related differences within these responses. Forty four male and female subjects aged 15 - 19 years volunteered to participate in this study; all pupils were First team members who competed in a variety of team and individual sports. Subjects participated in a battery of psychological, physiological and performance tests before and after competing in a practice session and during competitive league matches. The data were statistically analyzed for the various parameters under investigation. The results of the Sport Competition Anxiety Test indicated that the females, and the male team players had the highest competitive anxiety traits (CTA). The Task and Ego Orientation in Sport Questionnaire scores showed that most subjects have a general dominance of task orientation to sport. The results of the Physical Self-Perception Profile revealed that the females' poorer perception of their physical was not as substantial as their difference in CTA compared to males. Team participants, particularly the males, had a poorer self-image than individual sport counterparts. Elevated heart rate responses were observed prior to performing in a competitive ambience, with significant increases in team, rather than individual, players. The Evaluation of Task Demands revealed that team players, especially the females, perceived the match demands as significantly higher than the individual athletes. No significant differences were observed in the players' Evaluation of Perceived Strain. Neither were any significant differences observed in the players' ratings of their performance. In conclusion, although differences appear to exist between male and female responses within a competitive ambience, the magnitude of difference was far more notable between team and individual responses to competitive stress, particularly for competitive matches as opposed to practice sessions.
- Full Text:
- Date Issued: 1995
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