Dissertations / Theses on the topic 'Aerobic fitness'

Regular aerobic exercise has a wide range of positive effects on health and cognition. Exercise has been demonstrated to provide a particularly powerful and replicable method of triggering a wide range of structural changes within both human and animal brains. However, the details and mechanisms of these changes remain poorly understood. This thesis undertakes a comprehensive examination of the relationship between brain plasticity and aerobic exercise. A large, longitudinal experiment was conducted in which healthy but sedentary participants were scanned before and after six-weeks of monitored aerobic exercise. Increases in the volume of the anterior hippocampus were observed, as previously reported in an older cohort after a longer exercise intervention. Multimodal imaging methods allowed an in-depth exploration of the mechanisms underlying this volume change, which proved to be dominated by white matter changes rather than the vascular changes that have been previously reported. A surprising global change in the balance of CSF, blood, and brain tissue within the cranial cavity was also observed. Cross-sectional differences in memory and brain structure associated with fitness were also observed. The volume of the anterior hippocampus was shown to correlate with a measure of working memory. Higher cerebral blood volume throughout the brain was found to correlate with greater fitness and better working memory. Focal associations between fitness and magnetic susceptibility, a measure of iron content, were also observed in the basal ganglia. These findings demonstrate that aerobic fitness is associated with improved cognition and brain structure throughout the lifespan rather than simply acting to mitigate age related brain atrophy or accelerate brain development. Finally, a new pipeline was developed for analysing hippocampal morphometry using high-resolution, 7 Tesla scans. Striking variability in the convolution of the hippocampal surface is reported. This technique shows promise for imaging the precise nature of the change in hippocampal volume associated with aerobic exercise. This thesis adds to the evidence that aerobic exercise is a potent catalyst for behavioural and brain plasticity while also demonstrating that the mechanisms for those plastic changes are likely different than previously supposed. Future work will refine these measurement techniques, perhaps to a point where brain changes can be monitored on a single subject level. This work will provide an important tool to understand how best to utilize aerobic exercise to facilitate adaptive behavioural changes, mitigate the negative effects of ageing and disease on the brain, and maximize the benefits of active lifestyles.

Today, students are victims of stress associated with learning and unhealthy lifestyles. In addition, in our time Internet technology and other types of hanging out dominate, which do not involve mobility. Therefore, the importance of physical activity for students cannot be ignored. Now aerobic-fitness is widespread among young people. But not everyone can determine exactly what is hidden by the term.

Figure skating includes ice based locomotion, jumping and dance elements. It is limited by physiological, psychological, technical and tactical factors. Optimising performance requires guidance from coaches educated in; "Coaching", "Training", "Testing", "Nutrition" and "Biomechanics". AIMS: Acquire British coaches' self assessed knowledge levels. Independently evaluate coaches' efficacy. Identify an area of deficit in coach understanding. Using the area of coaching, "Testing", develop a valid and repeatable skating specific aerobic fitness test. Identify the role of aerobic fitness in competitive performance and its effect on a skill based jump element; An Axel. METHODS: The entire coaching population was surveyed. An objective multidimensional model measured efficacy in the respondent 12.5%. Pilot testing established a suitable track protocol for a progressive /O2 peak skating test (ISE test). 20 skaters performed the ISE test, running and laboratory V02 peak tests. 11 skaters repeated the ISE test twice. 10 skaters performed a videoed competitive routine simulation and 10 skaters performed Axels before and after an exhaustive drill. In both instances physiological, quantitative, qualitative and ISE " O2 peak were measured. RESULTS: Coaches rated their knowledge lowest and identified least methods of erudition available in "Testing" and "Biomechanics". Objective measurement identified mean coaching efficacy at 30%. ISE test VO2 peak was lower (p<0.002) but highly correlated (p<0.01) to laboratory V02. Linear regression adjusted ISE test values. Retrial repeatability fell between Bland and Altman limits. On ice "O2 peak was independent of routine heart rate and post exercise blood lactate but correlated to Axel take off (p<0.05) and height (p<0.01). These correlations were consistent in Axels' post exhaustive exercise (p<0.01). CONCLUSIONS: Testing is a coaching deficit which would benefit from research. The ISE test provides valid and repeatable V02 peak measures. Higher V02 peak does not reduce routine stress but influences Axel performance. Higher aerobic capacity improves Axel performance under physiological stress

The present study evaluated direct and indirect associations between aerobic fitness, executive control, and emotion regulation among a sample of children aged 8-12 years. To evaluate these associations, the study employed a cross-sectional design and full-information maximum likelihood (FIML) structural equation modeling. Although the hypothesized factor analytic model failed to converge, an alternative exploratory model allowed for the evaluation of associations between primary study variables. Results supported a moderate direct association between childhood aerobic fitness and executive control, a strong direct negative association between executive control and emotion regulation, and a moderate indirect association between aerobic fitness and emotion regulation through executive control. These findings provide preliminary evidence that executive control functions as a mediator between aerobic fitness and emotion regulation and may help explain the means by which aerobic exercise exerts its influence on emotional wellbeing among preadolescent children.

The recent American college of Sports Medicine Position Stand concerning the quantity and quality of exercise for developing cardiovascular fitness (1) suggests a need for more information concerning the rate of improvement in aerobic power as a function of age. Therefore, the purpose of this retrospective study was to assess whether the change in maximal oxygen uptake (AVO2max) following endurance training varies as a function of age. Subjects were healthy men (N=277) and women (N=161), ranging in age from 20-72 years, who completed an endurance training program (= 3-5 months) between 1972 and 1987. The standard training stimulus consisted of individualized aerobic exercise (walking, walk-jog, or jogging) at about 75-85% maximal heart rate reserve for = 30-60 minutes, 3-4 sessions per week. A description of the %OVO2max expressed in relative and absolute terms, ± SEE are presented below.Variable20-29 yrs30-39 yrs40-49 yrs50-59 yrs60-69 yrsM 9/6AV02max ml•kg-1-min-'17.1 ± 13.220.0 ± 11.817.3 ± 13.319.5 ± 13.719.8 ± 9.1M%%OV02maxLmin-112.6 ± 10.616.0 ± 11.514.7 ± 11.616.6 ± 15.116.2 ± 9.8F °/oA VO2max mlkg''•min-'16.3 ± 9.022.5 ± 13.119.0 ± 10.917.6 ± 13.415.4 ± 6.8F%OV02maxL.min-'15.2±12.321.7±12.716.6±11.515.7±13.411.9±9.8N=Men women)20(17)87(54)112(51)46(30)12(9)A stepwise multiple regression analysis was used to assess the relationship between age and %OVO2max in both relative and absolute units, after adjusting for other parameters known to effect the training response. After adjusting for pre-training VO2max.(ml-kg-1-min-1) there was a significant negative correlation between OVO2max and age in both men (r = -0.31, p < 0.01) and women(r = -0.37, p < 0.01). When expressed as %OVO2max (L•min-1), the resultsrevealed the same age trend as that observed for the relative unit. Since the AVO2max after =3-5 months of training decreased as a function of age, this study supported the contention that training adaptations may be attenuated with increased age.
School of Physical Education

Background: Performing aerobic exercise and maintaining high levels of aerobic fitness may have positive effects on both brain structure and function in older adults. Despite decades of research however, there is still a rather poor understanding of the neurocognitive mechanisms explaining the positive effects of aerobic exercise on cognition. Changes in prefrontal gray matter as well as dopaminergic neurotransmission in striatum are both candidate neurocognitive mechanisms. The main aims of this thesis are: 1. To investigate the effects of aerobic exercise and fitness on cognition and magnetic resonance imaging (MRI) derived gray matter volumes using data from a 6 month physical exercise intervention in older adults (Study I). 2. To simulate the effect of atrophy in longitudinal positron emission tomography (PET) which could pose a challenge to interpreting changes in longitudinal PET imaging (Study II). 3. To study the influence of aerobic exercise and fitness on the dopamine D2-receptor (D2R) system in striatum using [11C]raclopride PET as a potential mechanism for improved cognition (Study III). Results: In Study I, aerobic exercise was found to improve cognitive performance in a broad, rather than domain-specific sense. Moreover, aerobic fitness was related to prefrontal cortical thickness, and improved aerobic fitness over 6 months was related to increased hippocampal volume. In Study II, we identified areas in the striatum vulnerable to the effect of shrinkage, which should be considered in longitudinal PET imaging. Finally, in Study III, the effect of being aerobically fit, and improving fitness levels was found to impact dopaminergic neurotransmission in the striatum, which in turn mediated fitness-induced improvements in working memory updating performance. Conclusion: The findings in this thesis provide novel evidence regarding the neurocognitive mechanisms of aerobic exercise-induced improvements in cognition, and impacts the interpretation of longitudinal PET imaging. Performing aerobic exercise and staying aerobically fit at an older age have positive effects on cognition and brain systems important for memory and cognition. Specifically, fitness-induced changes to the dopaminergic system stands out as one novel neurocognitive mechanism explaining the positive effects of aerobic fitness on working-memory performance in healthy older adults.

Élite adult athletes are known to have physical and physiological characteristics specifically suited to their sport. However, it is not clear whether the observed adult differences arise because of training or whether the sport selects the individual with the appropriate characteristics.The purpose of this study was to compare and contrast the physical development of young athletes (8 - 19 yr) and in so doing provide an answer to this question. Development of anthropometric characteristics, sexual maturation, pulmonary function and aerobic power were assessed in a group of 232 boys and 222 girls. The athletes were a randomly selected group of young athletes who had demonstrated previous performance success or who were excepted to do so in the future. They came from 4 sports namely: soccer (all male); gymnastics (2:1 female to male ratio), swimming (1:1 sex ratio) and tennis (1:1 sex ratio). The subjects were assessed annually for three consecutive years. The adjusted mean (ANCOVA) height of male swimmers (161.6 ± 0.6 cm) was found to be significantly greater (P<0.01) than non-athletes (159.2 ± 0.4 cm), gymnasts (150.7 ± 0.8 cm) and soccer players (158.7 ± 0.6 cm) and adjusted body mass (51.3 ± 0.6 kg) significantly greater (P<0.01) than the other groups. These trends were also observed in females. When testicular volumes were compared, it was found that swimmers matured significantly earlier (P<0.05) than gymnasts, tennis players and a reference population of non athletes. Female gymnasts attained sexual maturation (indexed by menarche) on average (14.4 ± 0.2 yr) a year after the other sports and the general population. A positive correlation was found between menarcheal age in mothers and daughters (r=0.29 , P<0.05), suggesting a familial trait. The observed late sexual maturation of gymnast therefore suggests some form of sports specific selection. Swimmers had the highest initial lung volumes (P<0.001), a difference which did not change with time. However, as training began well before the subjects were tested it was not possible to determine whether these observed differences were present prior to training. When age, height and weight were controlled for VO₂ max in males significantly increased both pubertal development, although this pattern was not shown in females. Swimmers had the highest VO₂ max values at all ages.

Aerobic and anaerobic correlates of multiple sprint cycling performance. J. Strength Cond. Res. 20(4):792-798. 2006.--The aims of this study were to examine (a) the relationship between maximal oxygen uptake (O2max) and several performance indices of multiple sprint cycling; (b) the relationship between maximal accumulated oxygen deficit (MAOD) and those same performance indices; and (c) the influence of recovery duration on the magnitude of those relationships. Twenty-five physically active men completed a O2max test, a MAOD test, and 2 maximal intermittent (20 x 5 seconds) sprint cycling tests with contrasting recovery periods (10 seconds or 30 seconds). Mean +/- SD for age, height, and body mass were 20.6 +/- 1.5 years, 177.2 +/- 5.4 cm, and 78.2 +/- 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer with subsequent data normalized for body mass. Moderate (0.3 r < 0.5) positive correlations were observed between power output data and MAOD (range, 0.31-0.46; 95% confidence limits, -0.10 to 0.72). Moderate to large positive correlations also were observed between power output data and O2max, the magnitude of which increased as values were averaged across all sprints (range, 0.45-0.67; 95% confidence limits 0.07-0.84). Correlations between fatigue and O2max were greater in the intermittent protocol with 30-second recovery periods (r = -0.34; 95% confidence limits, 0.06 to -0.65). The results of this study reflect the complex energetics associated with multiple sprint work. Though the findings add support to the idea that multiple sprint sports demand a combination of speed and endurance, further longitudinal research is required to confirm the relative importance of these parameters.

Falls in people aged over 65 years account for the largest proportion of all injury-related deaths and hospitalisations within Australia. Falls contributed to 1,000 deaths and 50,000 hospitalisations in older people during 1998 (Commonwealth Department of Health and Aged Care 2001). It has been predicted that by 2016, 16% of the Australian population will be aged over 65 years (Australian Bureau of Statistics 1999) placing considerable pressure on the health care system. Furthermore, prospective studies have shown that 30-50% of people aged 65 years and over, will experience a fall (Tinetti et al. 1988b; Campbell et al. 1989; Lord et al. 1994b; Hill 1999; Brauer et al. 2000; Stalenhoef et al. 2002) and this figure increases exponentially with age (Lord et al. 1994b). Many physiological falls risk factors have been established including reduced leg strength, poor balance, impaired vision, slowed reaction time and proprioception deficits. However, little research has been conducted to determine whether performance on aerobic fitness tasks is also a physiological falls risk factor. Aerobic fitness has previously been related to an individual's ability to perform activities of daily living, which in turn has been linked to falls. It was therefore proposed that aerobic fitness might also be a risk factor for falls among community dwelling older people. This research aimed to provide clinical evidence to inform public health practice. This thesis comprised of four objectives: the first to find suitable measures of aerobic fitness for older people; the second investigated relationships between existing clinical tests and future falls; the third explored relationships between aerobic fitness tests and future falls; the final objective was to examine the independent relationships between falls and clinical and physiological characteristics. The participants were recruited through a random sample from the local electoral roll, with an average age of 73 ±6 years. Of the 87 participants who completed the prospective component of the study, 37% were male and 63% were female. Sixty-three participants (65%) reported no previous falls, 19 (20%) reported a single fall, and 16 (15%) reported two or more falls in the previous 12 months. The first objective required participants recruited from the community to take part in submaximal and maximal fitness tests in order to find suitable measures of aerobic fitness. A further objective was to determine whether older people were able to fulfil the 'standard' criteria for completion of a maximum oxygen consumption test. The measures used in this research included: maximum oxygen consumption, peak oxygen consumption, ventilatory threshold, oxygen uptake kinetics, oxygen deficit, efficiencies, oxygen consumption at zero, 30 and 50 watts, predicted max and Six-Minute Walk Test distance. Only weak relationships were observed between submaximal aerobic measures and peak oxygen consumption. Furthermore, only 54% of participants were able to fulfil the criteria to complete a test of maximum oxygen consumption, indicating it was not a suitable measure for use among a sample of community dwelling older people. Therefore submaximal aerobic variables were used in the following chapters. The second objective investigated the relationship between clinical measures and falls among older people and was carried out to enable comparisons between the population in this study and those described in the literature. This research found that the Timed Up and Go (TUG) test was the most sensitive of all clinical tests (including the Berg Balance Scale, Function Reach, Performance Oriented Mobility Assessment and Physiological Profile Assessment) for the assessment of future falls. The TUG requires participants to stand up, walk 3m, turn, walk back, and sit down. Time taken to complete the test is the recorded value. For this study, a cut-off value of 7-seconds was established, above which individuals were at increased risk of falls. Previous research suggested cut-off times of over 10s were appropriate for older people. However, this is the first study to assess falls prospectively and definitively find that the TUG can discriminate between future fallers and non-fallers. This research also investigated the differences in falls risk factors for functionally different subsamples, as defined by their ability to undertake and complete the cycle test. The participants who could complete the test had significantly better balance ability and strength than those unable to undertake or complete the cycle test. However, this inability to undertake or complete the cycle test was not itself a predictor of future falls. These two groups also differed in the relationships between clinical test results and falls risk. Participants in the no-cycle group had very similar results to that of the entire cohort. Even after adjustment for age, the TUG, foot and hand reaction times and knee flexion strength were all performed better by non-fallers than fallers. However, none of these differed between fallers and non-fallers for participants in the cycle group. This group had better balance ability and strength than the no-cycle group. These results indicated that the cycle group differed from the no-cycle group and the entire sample, further indicating that factors other than the physiological variables measured in this research influence falls risk in strong participants with good balance ability. Similar results were reported when aerobic tests and falls were investigated in the third objective. In the whole sample, the fallers walked significantly less distance than non-fallers for the 6-MWT. Similar results were found for participants in the no-cycle group but not the cycle group. All participants were able to complete the Six-Minute Walk Test (6-MWT) although only 74% were able to undertake and complete the cycle test. The fourth objective was to consider all measures from the previous chapters as potential predictors of falls. The variables most predictive of future falls were the TUG and having experienced one or more falls in the previous 12 months. As a result they could be used as screening tools for the identification of high-risk fallers who require referral for further assessment. This could be completed by a General Practitioner or Practice Nurse, which would ensure that screening is being undertaken in the wider population. If the patient is at high risk they should be referred for falls risk factor assessment to determine an optimal tailored intervention to reduce future falls. Low risk patients should be referred for preventive evidence-based activities. These steps can potentially improve quality of life for individuals, and if effective in preventing future falls, will result in reduced costs to the individual and the Australian public. The results of this work demonstrate that the best screening tests are simple tasks like the TUG and asking an individual if they have experienced a fall in the last 12 months. This research also found that strong, mobile older people who could undertake and complete a submaximal cycle ergometer test, still experienced falls in the following 12 months, although the causes of this are currently unknown. This research showed that physiological falls risk factors are less relevant as these highly functional older people do not have physiological deficits. However, this research found that the 6-MWT showed promise as a predictor of falls in a group who could not complete a submaximal cycle ergometer test, who had lower strength, balance and functional fitness scores than a group who could complete this cycle test. The results showed that physiological falls risk factors are still very important for older people with lower physical abilities, and this is where aerobic fitness may still be related to falls. While the association between aerobic fitness and falls remains unclear, these are novel and provocative findings highlighting the need for future falls risk investigations to consider aerobic fitness as a contributing factor.

Falls in people aged over 65 years account for the largest proportion of all injury-related deaths and hospitalisations within Australia. Falls contributed to 1,000 deaths and 50,000 hospitalisations in older people during 1998 (Commonwealth Department of Health and Aged Care 2001). It has been predicted that by 2016, 16% of the Australian population will be aged over 65 years (Australian Bureau of Statistics 1999) placing considerable pressure on the health care system. Furthermore, prospective studies have shown that 30-50% of people aged 65 years and over, will experience a fall (Tinetti et al. 1988b; Campbell et al. 1989; Lord et al. 1994b; Hill 1999; Brauer et al. 2000; Stalenhoef et al. 2002) and this figure increases exponentially with age (Lord et al. 1994b). Many physiological falls risk factors have been established including reduced leg strength, poor balance, impaired vision, slowed reaction time and proprioception deficits. However, little research has been conducted to determine whether performance on aerobic fitness tasks is also a physiological falls risk factor. Aerobic fitness has previously been related to an individual's ability to perform activities of daily living, which in turn has been linked to falls. It was therefore proposed that aerobic fitness might also be a risk factor for falls among community dwelling older people. This research aimed to provide clinical evidence to inform public health practice. This thesis comprised of four objectives: the first to find suitable measures of aerobic fitness for older people; the second investigated relationships between existing clinical tests and future falls; the third explored relationships between aerobic fitness tests and future falls; the final objective was to examine the independent relationships between falls and clinical and physiological characteristics. The participants were recruited through a random sample from the local electoral roll, with an average age of 73 ±6 years. Of the 87 participants who completed the prospective component of the study, 37% were male and 63% were female. Sixty-three participants (65%) reported no previous falls, 19 (20%) reported a single fall, and 16 (15%) reported two or more falls in the previous 12 months. The first objective required participants recruited from the community to take part in submaximal and maximal fitness tests in order to find suitable measures of aerobic fitness. A further objective was to determine whether older people were able to fulfil the 'standard' criteria for completion of a maximum oxygen consumption test. The measures used in this research included: maximum oxygen consumption, peak oxygen consumption, ventilatory threshold, oxygen uptake kinetics, oxygen deficit, efficiencies, oxygen consumption at zero, 30 and 50 watts, predicted max and Six-Minute Walk Test distance. Only weak relationships were observed between submaximal aerobic measures and peak oxygen consumption. Furthermore, only 54% of participants were able to fulfil the criteria to complete a test of maximum oxygen consumption, indicating it was not a suitable measure for use among a sample of community dwelling older people. Therefore submaximal aerobic variables were used in the following chapters. The second objective investigated the relationship between clinical measures and falls among older people and was carried out to enable comparisons between the population in this study and those described in the literature. This research found that the Timed Up and Go (TUG) test was the most sensitive of all clinical tests (including the Berg Balance Scale, Function Reach, Performance Oriented Mobility Assessment and Physiological Profile Assessment) for the assessment of future falls. The TUG requires participants to stand up, walk 3m, turn, walk back, and sit down. Time taken to complete the test is the recorded value. For this study, a cut-off value of 7-seconds was established, above which individuals were at increased risk of falls. Previous research suggested cut-off times of over 10s were appropriate for older people. However, this is the first study to assess falls prospectively and definitively find that the TUG can discriminate between future fallers and non-fallers. This research also investigated the differences in falls risk factors for functionally different subsamples, as defined by their ability to undertake and complete the cycle test. The participants who could complete the test had significantly better balance ability and strength than those unable to undertake or complete the cycle test. However, this inability to undertake or complete the cycle test was not itself a predictor of future falls. These two groups also differed in the relationships between clinical test results and falls risk. Participants in the no-cycle group had very similar results to that of the entire cohort. Even after adjustment for age, the TUG, foot and hand reaction times and knee flexion strength were all performed better by non-fallers than fallers. However, none of these differed between fallers and non-fallers for participants in the cycle group. This group had better balance ability and strength than the no-cycle group. These results indicated that the cycle group differed from the no-cycle group and the entire sample, further indicating that factors other than the physiological variables measured in this research influence falls risk in strong participants with good balance ability. Similar results were reported when aerobic tests and falls were investigated in the third objective. In the whole sample, the fallers walked significantly less distance than non-fallers for the 6-MWT. Similar results were found for participants in the no-cycle group but not the cycle group. All participants were able to complete the Six-Minute Walk Test (6-MWT) although only 74% were able to undertake and complete the cycle test. The fourth objective was to consider all measures from the previous chapters as potential predictors of falls. The variables most predictive of future falls were the TUG and having experienced one or more falls in the previous 12 months. As a result they could be used as screening tools for the identification of high-risk fallers who require referral for further assessment. This could be completed by a General Practitioner or Practice Nurse, which would ensure that screening is being undertaken in the wider population. If the patient is at high risk they should be referred for falls risk factor assessment to determine an optimal tailored intervention to reduce future falls. Low risk patients should be referred for preventive evidence-based activities. These steps can potentially improve quality of life for individuals, and if effective in preventing future falls, will result in reduced costs to the individual and the Australian public. The results of this work demonstrate that the best screening tests are simple tasks like the TUG and asking an individual if they have experienced a fall in the last 12 months. This research also found that strong, mobile older people who could undertake and complete a submaximal cycle ergometer test, still experienced falls in the following 12 months, although the causes of this are currently unknown. This research showed that physiological falls risk factors are less relevant as these highly functional older people do not have physiological deficits. However, this research found that the 6-MWT showed promise as a predictor of falls in a group who could not complete a submaximal cycle ergometer test, who had lower strength, balance and functional fitness scores than a group who could complete this cycle test. The results showed that physiological falls risk factors are still very important for older people with lower physical abilities, and this is where aerobic fitness may still be related to falls. While the association between aerobic fitness and falls remains unclear, these are novel and provocative findings highlighting the need for future falls risk investigations to consider aerobic fitness as a contributing factor.

Introduktion: Vikten av att testa idrottares aeroba effekt idrottsnära har länge varit känd. Skating Multistage Aerobic Test (SMAT) är ett idrottsspecifikt test för ishockeyspelare som utvecklades med unga individer men som idag används på vuxna ishockeyspelare utan att någon validering har skett med den vuxna åldersgruppen. Syfte och frågeställning: En experimentell pilotstudie utfördes med syftet att validera SMAT-protokollet på vuxna ishockeyspelare samt undersöka vilken tillförlitlighet SMAT-protokollet har för att uppskatta testvärdet hos vuxna ishockeyspelare jämfört med det uppmätta värdet. Metod: 6 aktiva ishockeyspelare i division 2 (Ålder: 27,6 ± SD 7,2 år) deltog i studien. Syreupptagningen mättes konstant under utförandet av SMAT med Jaeger Oxycon Mobile system och jämfördes med SMAT protokollets erhållna värden. VO2 platå, blodlaktat, respiratoriska kvot (RER) och % av maxpuls granskades för att undersöka om testet var tillförlitligt. Resultat: På nivå ett var medelvärdet på samtliga 6 deltagares testvärde 24,52 ml syre/min/kg i jämförelse med SMAT protokollets erhållna testvärde på 27,7 ml syre/min/kg. Medeltestvärdet för deltagarna visade en stigande skillnad med SMAT protokollets värden i och med nivåökningarna, på nivå 13 var skillnaden 53,37 (Jaeger systemet) kontra 71,6 ml syre/min/kg (SMAT-protokollet). Samma trend sågs på individuell nivå.  5 av 6 deltagare uppnådde en VO2 platå och ≥95% av maxpuls. Laktatnivåerna innan testet var 0,7 till 1,7 och efter testet 5,6 till 13,6 varav 2 deltagare uppnådde gränsvärdet (≥8 mmol/L-1). 4 av 6 uppnådde RER gränsen på ≥1.10. Diskussion: Skillnaderna i testvärdena mellan SMAT och det uppmätta värdet tros blivit påverkat av ungas arbetsekonomi (skridskoteknik), på grund av sämre arbetsekonomi så kräver unga en högre syreförbrukning för ett givet arbete. Den anaeroba kapaciteten kan också ha påverkat då vuxna har en större förmåga att utnyttja det anaeroba systemet. Slutsats: Resultatet tyder på att SMAT protokollet inte är tillförlitligt för att mäta testvärdet hos vuxna ishockeyspelare.

The investigations described in this thesis were conducted in order to increase the understanding of the relationships between physical activity, aerobic fitness, body composition, asthma, and asthma severity in children and adolescents. This was largely achieved by examining the aforementioned factors in a sizeable population of Melbourne school children and adolescents. However, during the course of the school-based testing, it became apparent that the severe asthmatic category was under-represented, typical of the current literature. Thus, effort was also directed at addressing this knowledge gap by examining a severely asthmatic cohort in a laboratory-based setting. The outcomes generated by these investigations can be summarised as follows: 1) In ‘school-tested’ youth aged 10 to 14 years, prevalence rates of overweight and obesity were 19.1% and 4.0%, respectively. Approximately 16% of participants also suffered from asthma. These rates appear to be representative of similarly aged children and adolescents within Australia. The latter observation also adds weight to the view that asthma prevalence has attenuated in recent years. In addition, overweight and obesity were more prevalent in asthmatics than non-asthmatics, supporting the proposed notion of an asthma-obesity association. 2) Asthmatic and non-asthmatic young people had comparable aerobic fitness and daily physical activity levels and the severity of disease did not influence aerobic fitness nor involvement in physical activity. Males possessed greater aerobic fitness and physical activity levels and had a lower percentage body fat compared to age-matched females, independent of asthma status (i.e. asthmatic or non-asthmatic). 3) There was a significant inverse relationship between aerobic fitness and markers of increased body fat among non-asthmatic children and adolescents, even after corrections to aerobic fitness were made for fat free mass. Differences in daily physical activity could only partially explain this association. In fact, the current findings suggest that decreased levels of daily physical activity are not the cause of the increased overweight/obesity prevalence among this sample, and that physical activity lacks a strong link to paediatric overweight/obesity in this population. These findings were also present in asthmatic youth. 4) Severely asthmatic youth, premedicated with bronchodilator, had aerobic fitness levels comparable to their non-asthmatic and less severe asthmatic peers. This finding indicates that severely asthmatic youngsters should be able to train at work intensities sufficient to bring about improvements in cardio-respiratory fitness without any added functional limitation due to their condition. In addition, a state of well-controlled asthma (as were the severe asthmatics in this study) afforded the participants the ability to engage in similar levels of physical activity as their non-asthmatic or less severe asthmatic peers. In agreement with data from the ‘school-tested’ asthmatics, a significantly greater proportion of severely asthmatic participants were overweight or obese in comparison to their non-asthmatic peers. These findings (i) highlight the association between aerobic fitness and overweight/obesity; (ii) suggested that decreased levels of daily physical activity were not associated with the increased overweight/obesity prevalence in a youth sample within Australia; (iii) emphasize that well-controlled asthmatic young people can undertake levels of physical activity and achieve cardio-respiratory fitness similar to that of their non-asthmatic peers, independent of asthma severity, and; (iv) indicated that asthma is either a risk factor for overweight and obesity or that overweight and obesity may precede asthma.

The investigations described in this thesis were conducted in order to increase the understanding of the relationships between physical activity, aerobic fitness, body composition, asthma, and asthma severity in children and adolescents. This was largely achieved by examining the aforementioned factors in a sizeable population of Melbourne school children and adolescents. However, during the course of the school-based testing, it became apparent that the severe asthmatic category was under-represented, typical of the current literature.Thus, effort was also directed at addressing this knowledge gap by examining a severely asthmatic cohort in a laboratory-based setting. The outcomes generated by these investigations can be summarised as follows: 1) In 'school-tested' youth aged 10 to 14 years, prevalence rates of overweight and obesity were 19.1% and 4.0%, respectively. Approximately 16% of participants also suffered from asthma. These rates appear to be representative of similarly aged children and adolescents within Australia. The latter observation also adds weight to the view that asthma prevalence has attenuated in recent years. In addition, overweight and obesity were more prevalent in asthmatics than non-asthmatics, supporting the proposed notion of an asthma-obesity association. 2) Asthmatic and non-asthmatic young people had comparable aerobic fitness and daily physical activity levels and the severity of disease did not influence aerobic fitness nor involvement in physical activity. Males possessed greater aerobic fitness and physical activity levels and had a lower percentage body fat compared to age-matched females, independent of asthma status (i.e. asthmatic or non-asthmatic). 3) There was a significant inverse relationship between aerobic fitness and markers of increased body fat among non-asthmatic children and adolescents, even after corrections to aerobic fitness were made for fat free mass.;Differences in daily physical activity could only partially explain this association. In fact, the current findings suggest that decreased levels of daily physical activity are not the cause of the increased overweight/obesity prevalence among this sample, and that physical activity lacks a strong link to paediatric overweight/obesity in this population. These findings were also present in asthmatic youth. 4) Severely asthmatic youth, premedicated with bronchodilator, had aerobic fitness levels comparable to their non-asthmatic and less severe asthmatic peers. This finding indicates that severely asthmatic youngsters should be able to train at work intensities sufficient to bring about improvements in cardio-respiratory fitness without any added functional limitation due to their condition. In addition, a state of well-controlled asthma (as were the severe asthmatics in this study) afforded the participants the ability to engage in similar levels of physical activity as their non-asthmatic or less severe asthmatic peers. In agreement with data from the 'school-tested' asthmatics, a significantly greater proportion of severely asthmatic participants were overweight or obese in comparison to their non-asthmatic peers. These findings (i) highlight the association between aerobic fitness and overweight/obesity; (ii) suggested that decreased levels of daily physical activity were not associated with the increased overweight/obesity prevalence in a youth sample within Australia; (iii) emphasize that well-controlled asthmatic young people can undertake levels of physical activity and achieve cardio-respiratory fitness similar to that of their non-asthmatic peers, independent of asthma severity, and; (iv) indicated that asthma is either a risk factor for overweight and obesity or that overweight and obesity may precede asthma.

Background: The high frequency of emergency responses and the variety of response environments for firefighting and emergency medical services dictate a potential for high work demands and an increasing need for maintaining above average physical fitness. This study makes use of a retrospective occupational cohort study design to explore the relationships between measures of fitness and injury outcomes. Methods: Data were collected from annual medical exams and injury surveillance records recorded for the years 2004-2009 among commissioned employees of the Tucson Fire Department. Fitness was assessed and contrasted via a submaximal estimate of aerobic capacity and a developed metric and score for comprehensive "fire fitness" encompassing seven separate measures for strength, endurance, flexibility, body composition and aerobic fitness. Individual fitness scores were classified as 'high fit', 'fit', and 'less fit'. The association between the fitness measures and injuries was evaluated using two approaches: log-binomial and time-to-event analyses. Results: The annual injury incidence rate averaged 17.7 per 100 employees. One-third of all injuries (32.9%) resulted from physical exercise activities, while patient transport, training drills, and fireground operations resulted in 16.9%, 11.1% and 10.2% of injuries, respectively. For all job operations, sprains and strains were the most prevalent type of injury, followed by contusions and lacerations. The reliability of fitness and clinical measures showed mean flexibility, grip strength, percent body fat, and resting heart rate each had intraclass correlations (ICC) values above 0.5, suggesting fair to good reliability. In contrast, mean VO2max was an unreliable measure with an ICC of 0.27. Hazard ratios from time-to-event analyses indicated that increases in cardiorespiratory fitness were significantly associated with decreased risk against injury. Similarly, decreases in comprehensive "fire fitness" were associated with an increased risk of injury. Conclusions: These findings add support that improving one's fitness reduces the likelihood of injury. Future research should focus on the relationship between fitness, performance and health outcomes. Individual level fitness improvements should be objectively measured and designed within the functional limitations of that individual, and without subjecting the person to injury in that process.

Thesis (M.S.)--Wake Forest University. Dept. of Health and Exercise Science, 2009.
Title from electronic thesis title page. Thesis advisor: Patricia A. Nixon. Vita. Includes bibliographical references (p. 44-49).

Regular aerobic exercise may reduce cardiovascular disease (CVD) risk in part by lowering the concentration of inflammatory markers such as C-reactive protein (CRP). While studies in diseased populations have shown significant decreases in CRP concentrations with regular aerobic training, little has been conclusively determined regarding the effects of aerobic training on CRP concentrations in apparently healthy, untrained populations who may not be adequately screened for CVD risk by traditional methods. PURPOSE: To examine the effects of a 17-wk half marathon training program (TP) on CRP concentrations, aerobic fitness, and body composition in apparently healthy, untrained men. METHODS: Twenty men (29.3 ± 1.0 yr, 37.0 ± 1.6 mL•kg-1•min-1 VO2max, 29.1 ± 1.8% body fat) registered as training subjects (TRN) in a 17-wk half marathon TP. An additional 22 men (27.8 ± 1.4 yr, 38.8 ± 1.0 mL•kg-1•min-1 VO2max, 26.8 ± 1.4% BF) served as controls (CON). Fasting blood samples were taken at four time points over the TP and were analyzed for CRP and interleukin-6 (IL-6) concentrations. Aerobic capacity (VO2max) and body fat (BF%) were measured before and after the TP. RESULTS: No significant changes in CRP (P=0.69) or IL-6 concentrations (P=0.73) were seen in TRN as a result of the TP despite significant improvements in VO2max (42.2 ± 1.9 ml•kg-1•min-1, P<0.0001), resting heart rate (P =0.004), BF% (P =0.03) and BMI (P =0.05). No significant changes in CRP, aerobic fitness, BMI or BF% were detected in CON over time. CONCLUSION: Moderate, long-term aerobic training does not appear to affect CRP concentrations in apparently healthy, untrained men despite significant improvements in BW, BF%, BMI, and VO2max.

Thesis (M.A.)--University of New Orleans, 2005.
Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Arts in Human Performance and Health Promotion"--Thesis t.p. Vita. Includes bibliographical references.

Background: Several cross-sectional studies have reported lower aerobic fitness among fibromyalgia (FM) patients compared to healthy controls. At present it is unknown whether the inferior aerobic fitness is a cause or a consequence of the illness. Objective: To examine if female FM patients have the same ability to enhance their aerobic fitness as healthy sedentary controls matched on age and BMI. A second objective was to investigate whether the FM patients experience an increase in pressure pain threshold (PPT) following an aerobic exercise program. Methods: Fifty subjects (25 FM patients, 25 controls) were enrolled to a 12 week aerobic exercise program. The exercise program consisted of ergometer cycling two times a week (each session 45-55 min) at low to moderate intensity. An incremental ergometer test was performed to determine anaerobic threshold (AT), and exercise intensity was deduced from the AT data acquired. Main outcome was changes in spirometric values and watt production at AT. Second outcome was changes in PPTs measured by an algometer. Results: FM patients were equally exercisable as healthy matched sedentary controls. No significant differences were found in average changes in VO2 (P=0.53) and watt production (P=0.56) at AT following the exercise program. However, FM patients had lower VO2 and watt production compared to controls at both the pre- and post test (P<0.03 for all comparisons). No significant increase in PPT was observed within the FM group following the exercise program (P>0.1 for all recorded PPT sits). Discussion: Aerobic exercise with low to moderate intensity enhances aerobic fitness in FM patients to the same extent as in healthy sedentary controls. A substantial lower aerobic fitness was found in the FM patients at both pre- and post test. These findings indicate that the common observation of low aerobic fitness among FM patients is related to inactivity rather than the illness.

The search for genes that influence human performance and health constitutes a popular topic of current research. One such genetic constituent that has caused much interest over the last 20 years is the angiotensin converting enzyme insertion/deletion polymorphism (ACE I/Dp). There is much controversy in the literature regarding the role (if any) of this polymorphism as effects and effect size vary between populations of different origin and training status. The aim of this thesis was to analyse at the whole organism level whether skeletal muscle plasticity explains the association of the ACE lfD polymorphism with metabolic fitness. Regular endurance exercise reduces the risk of a plethora of diseases, but the exact molecular mechanisms are not fully understood - the ability of muscle to adapt to exercise stimulus is key. Trained individuals demonstrated clear physiological differences of aerobic processes such as increased oxygen usage, greater power output and reduced body rat that would be expected (T-Test: p